Insertion of one, two, and three molecules of alkyne into the Pd-C bond of ortho-palladated primary and secondary arylalkylamines

Organometallics 2009, 28, 4175–4195 4175

DOI: 10.1021/om9002895

Insertion of One, Two, and Three Molecules of Alkyne into the Pd-C

Bond of Ortho-palladated Primary and Secondary Arylalkylamines

ꢀ

Jose Vicente, Isabel Saura-Llamas,* and Juana Turpın

´ ´

Grupo de Quımica Organometalica, Departamento de Quımica Inorganica, Facultad de Quımica,

ꢀ

Universidad de Murcia, E-30071 Murcia, Spain

´

ꢀ

Delia Bautista

SAI, Universidad de Murcia, E-30071 Murcia, Spain

Carmen Ramırez de Arellano

´

ꢀ

Departamento de Quımica Organica, Universidad de Valencia, E-46100 Valencia, Spain

Peter G. Jones

Institut fu€r Anorganische und Analytische Chemie, Technische Universita€t Braunschweig, Postfach 3329,

38023 Braunschweig, Germany

Received April 16, 2009

The ortho-metalated complex [Pd₂{κ²(C,N)-C₆H₄CH₂CH₂NHMe-2}₂(μ-Br)₂] (1) can be prepared by

refluxing a 1:1 mixture of Pd(OAc)₂and N-methylphenethylamine in acetonitrile, followed by addition of

an excess of NaBr. Complex 1 reacts with PPh₃to give the mononuclear derivative [Pd{κ²(C,N)-

C₆H₄CH₂CH₂NHMe-2}Br(PPh₃)] (2). The cationic complex [Pd{κ²(C,N)-C₆H₄CH₂CH₂NHMe-2}(py)₂]-

ClO₄(3) can be obtained by reacting 1 with AgClO₄and pyridine. The previously reported com-

plex [Pd₂{κ²(C,N)-C₆H₄CH₂NHCH₂Ph-2}₂(μ-Br)₂] (A) reacts with PhCtCCO₂R (R=Me, Et) to

give the monoinserted derivatives [Pd₂{κ²(C,N)-C(Ph)dC(CO₂R)C₆H₄CH₂NHCH₂Ph-2}₂(μ-Br)₂] (R=

Me (4a), Et (4b)). These dimers react with neutral ligands (L=PPh₃, ^tBuNC) in a 2:1 molar ratio to afford

the monomeric complexes [Pd{κ²(C,N)-C(Ph)dC(CO₂R)C₆H₄CH₂NHCH₂Ph-2}Br(L)] (L=PPh₃,

R=Me (5a), Et (5b); L=^tBuNC, R=Me (6a), Et (6b)). The complexes [Pd₂{κ²(C,N)-C₆H₃CH₂NH₂-

2,X-5}₂(μ-Br)₂] (X=Cl (C), F (D), NO₂(E)) react with RCtCR (R=Et, Ph) to give [Pd{κ²(C,N)-C(R)d

C(R)C(R)dC(R)C₆H₃CH₂NH₂-2,X-5}Br] (X=Cl, R=Et (7a), Ph (7b); X=F, R=Et (8a), Ph (8b);

X=NO₂, R=Ph (9)) through a double insertion of the alkyne into the Pd-C bond. Complexes A

and D react with PhCtCCO₂R in molar ratio 1:6-7 to afford a mixture of di-inserted head-to-tail and

tail-to-tail isomers [Pd{κ²(C,N)-C(R⁰)dC(R⁰⁰)C(Ph)dC(CO₂R)C₆H₄CH₂NHCH₂Ph-2}Br] (R=Me,

R⁰=Ph, R⁰⁰=CO₂Me (10a); R=Me, R⁰=CO₂Me, R⁰⁰=Ph (10b); R=Et, R⁰=Ph, R⁰⁰=CO₂Et (11a);

R=Et, R⁰=CO₂Et, R⁰⁰=Ph (11b)) and [Pd{κ²(C,N)-C(R⁰)dC(R⁰⁰)C(Ph)dC(CO₂Et)C₆H₃CH₂NH₂-2,-

F-5}Br] (R⁰=Ph, R⁰⁰=CO₂Et (12a); R⁰=CO₂Et, R⁰⁰=Ph (12b)). CO further inserts into the Pd-C bond of

complexes 7a,b and 8a,b to give the 10-membered palladacycles [Pd₂{κ²(C,N)-C(O)C(R)dC(R)C(R)d

C(R)C₆H₃CH₂NH₂-2,X-5}₂(μ-Br)₂] (X=Cl, R = Et (13a), Ph (13b); X=F, R = Et (14a), Ph (14b)).

Complexes A-E, [Pd₂{κ²(C,N)-C₆H₄CH₂CR₂NH₂-2}₂(μ-X)₂] (X=Br, R=H (F); X=Cl, R=Me, (G))

and 1 react with dimethylacetylene dicarboxylate (DMAD) to yield the tri-inserted products [Pd{κ³-

(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C(CO₂Me)C₆H₃CH₂NHR-2,R⁰-5}Br] (R=H, R⁰=OMe (15), Cl (16),

F (17); R=CH₂Ph, R⁰=H (18)) and [Pd{κ³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C(CO₂Me)C₆H₄CH₂-

CR₂NHR⁰-2}X] (X=Br, R=R⁰=H (19); X=Cl, R=Me, R⁰=H (20); X=Cl, R=H, R⁰=Me (21)),

which contain a cyclopentadienyl unit. Complex 18 reacts with TlOTf and neutral ligands to give [Pd{κ³(O,

C,N)-OdC(OMe){C₅(CO₂Me)₄}C(CO₂Me)C₆H₄CH₂NHCH₂Ph-2}(L)]OTf (L = H₂O (22), py (23)).

Reaction of complex A with an excess of 2-butyne for long periods of time affords the coordination

derivative 24, probably emerging from tri-insertion of the alkyne into the Pd-C bond, followed by an

internal cyclization and β-hydrogen abstraction. When complex G reacts with an excess of 2-butyne and

TlOTf, the tri-inserted product 25 is obtained, which also contains a C₅R₅unit, although in this case,

coordination around the palladium atom is completed by one CdC bond of the cyclopentadienyl unit. The

crystal structures of complexes 2, 5a, 6b, 7a, 7b 3DMSO, 9, 14a 2DMSO, 18, 21, 24, and 25 have been

3

solved by X-ray diffraction. In all these structures, the palladium atom shows a distorted or slightly

distorted square-planar environment, except in complex 14a, where Pd(II) exhibits a distorted trigonal-

bipyramidal geometry.

*Corresponding author. E-mail: jvs1@um.es, ims@um.es.

r

2009 American Chemical Society

Published on Web 06/16/2009

pubs.acs.org/Organometallics

4176 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

Introduction

Scheme 1. Stepwise Synthesis of Mono-, Di-, and Tri-inserted

Complexes

The insertion of alkynes into the Pd-C bond of aryl

complexes has received great attention, as this reaction is

involved in many stoichiometric and catalytic palladium-

mediated organic transformations.^1-19When ortho-meta-

lated tertiary benzylamines are used as starting materials,

enlarged palladacycles emerging from insertion of one, two,

or three molecules of the alkyne into the Pd-C bond can be

isolated.^4,6,7,20-24Depalladation of these organometallic

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intermediates leads to the selective syntheses of interesting

C- and N-heterocycles.^6-8,23,25-29

The mechanism of these insertion reactions has been

widely studied,^{3,4,6,7,23,29-35}and it is generally accepted that

(1) the multi-insertion reaction takes place sequentially

(Scheme 1);^4,23,33(2) the rate-determining step is the forma-

tion of the monoinsertion derivative;³⁵and (3) for each

insertion, the first step is the formation of a complex in

which the alkyne is η²-bonded to the metal,^30,32followed by

the migratory insertion of the coordinated alkyne into the

Pd-C bond to form a vinyl-palladated complex.^7,29,31,35The

isolated product depends greatly on the relative rates of the

various steps.^3,6,34Thus, monoinserted derivatives are diffi-

cult to prepare if the rate of the second insertion is much

greater than the first one, and the tri-inserted derivatives

cannot be obtained if isomerization of the di-inserted inter-

mediate is considerably faster than the insertion of a third

molecule of alkyne into the Pd-C bond. Also, the rate of the

various steps depends on the reaction conditions, the elec-

tronic and steric properties of the alkyne, the cyclometalated

ꢀ

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Article

Organometallics, Vol. 28, No. 14, 2009 4177

Chart 1. Orthopalladated Complexes Derived from Arylalkyla-

mines Used as Starting Materials for the Insertion Reactions of

Alkynes

Scheme 2. Cyclopalladation of N-Methylphenethylamine and

Synthesis of Neutral and Cationic Derivatives

and secondary arylalkylamines with three molecules of

internal alkynes, which has never been tried before with

cyclometalated phenethylamines, and in one case (i.e., when

benzylamine is reacted for long periods of time with 2-

butyne) leads to an unprecedented coordination complex;

and (5) the insertion of CO into the Pd-C bond of some

di-inserted complexes to give acyl derivatives in which the

palladium atom shows a distorted trigonal-bipyramidal

geometry.

To the best of our knowledge, there are few articles

reporting simultaneously the synthesis and characterization

of organometallic complexes derived from the insertion

of one, two, and three molecules of alkynes into the Pd-C

bond of N-palladacycles.^22,24,44

ligand, and the nature of the other groups coordinated to

palladium.^{2,4,7,10,20,33,36,37}

The recent availability of a general method for cyclo-

metalating primary arylalkylamines^38-40motivated us to

extend the study of the insertion reactions of alkynes into

the Pd-C bond of ortho-palladated primary benzyl-

and phenethylamines and also of some secondary amines.

There are only a few precedents for these reactions (most

of them previously reported by us) involving cyclometalated

benzylamines. Thus the following complexes are known:

(1) di-inserted derivatives of cyclopalladated R-methyl-

benzylamine,⁴¹N-methyl-3,4-dimethoxybenzylamine,⁶and

dibenzylamine,⁴²and (2) tri-inserted derivatives of cyclo-

metalated R-methylbenzylamine⁴¹and R-methyl-4-nitroben-

zylamine.⁴³

In this paper we present (1) the facile ortho palla-

dation of N-methylphenethylamine, which is the first exam-

ple of this kind of reaction for a secondary phenethylamine;

(2) the synthesis and characterization of the first pallada-

cycles derived from insertion of one molecule of alkyne

into the Pd-C bond of a secondary benzylamine; (3) the

reaction of ortho-metalated primary and secondary arylalk-

ylamines (Chart 1) with two molecules of internal alkynes,

which only allows the synthesis of organometallic deriva-

tives when the starting material contains a five-membered

palladacycle; (4) the reaction of ortho-metalated primary

Results and Discussion

Synthesis and Structure of Ortho-metalated Complexes.

The ortho palladation of N-methylphenethylamine (C₆H₅-

CH₂CH₂NHMe) was easily achieved by refluxing a 1:1

mixture of the free amine and Pd(OAc)₂in acetonitrile for

5 h. Treatment of the reaction mixture with an excess of

NaBr allowed the isolation of the ortho-metalated complex

[Pd₂{κ²(C,N)-C₆H₄CH₂CH₂NHMe-2}₂(μ-Br)₂] (1) in good

yield (65%). This process is the first reported example of

the ortho palladation of a secondary phenethylamine.

Complex 1 reacts with PPh₃(molar ratio=1:2) to give the

mononuclear complex [Pd{κ²(C,N)-C₆H₄CH₂CH₂NHMe-2}-

Br(PPh₃)] (2) and with AgClO₄and pyridine (molar ratio =

1:2:2) to give the cationic complex [Pd{κ²(C,N)-C₆H₄CH₂-

CH₂NHMe-2}(py)₂]ClO₄(3) (Scheme 2).

The ¹H NMR spectrum of complex 1 shows the existence

in solution of only one isomer that we assume to have a

transoid geometry, as has been described for most halogen-

bridged dimers containing orthopalladated amines.^42,45

Complexes 1-3 show similar patterns for the phenethyl

H3-H5 aromatic protons (Chart 1), but H6 is significantly

shifted to lower frequencies for 2 (6.49 ppm) and 3 (6.52 ppm)

than 1 (7.39 ppm) because of the anisotropic shielding from

the phenyl or pyridine ring.⁴⁶

(36) Maassarani, F.; Pfeffer, M.; Van Koten, G. Organometallics

1989, 8, 871.

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Wilis, A. C.; Rae, A. D. Organometallics 2002, 21, 2041.

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de Arellano, M. C. Organometallics 1997, 16, 826.

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M. C. Organometallics 2003, 22, 5513.

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28, 39.

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M. C.; Jones, P. G. Organometallics 1999, 18, 2683.

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4178 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

Figure 1. X-ray thermal ellipsoid plot of 2 (50% probability)

showing the labeling scheme (hydrogen atoms of PPh₃have

˚

been omitted for clarity). Selected bond lengths (A) and angles

Figure 2. X-ray packing view showing the dimers formed

through N(1)-H(01) Br(1B) hydrogen bonds in complex 2

(deg): Pd(1)-Br(1)=2.5521(4), Pd(1)-N(1)=2.147(2), Pd(1)-

C(1)=2.004(3), Pd(1)-P(1)=2.2553(8); C(1)-Pd(1)-N(1)=

87.64(11), C(1)-Pd(1)-P(1) = 93.77(8), N(1)-Pd(1)-Br(1) =

85.74(7), P(1)-Pd(1)-Br(1)=94.94(2).

3 3 3

˚

(1B: -x, y, -z+1/2; N(1) Br(1B)=3.564(3) A, H(01) Br-

3 3 3

˚

(1B)=2.89(4) A, N(1)-H(01) Br(1B)=134(3)°). Only Pd and

atoms involved in the hydrogen bonding have been labeled.

3 3 3

The crystal structure of complex 2 (Figure 1) shows

the palladium atom in a distorted square-planar environ-

through a pair of hydrogen bonds between the bromine

atoms and the NH₂groups (Figure 2).

˚

ment (mean deviation from the plane 0.173 A) with

Very recently, Buchwald et al.⁴⁹have reported the synth-

esis of two ortho-metalated N-methylphenethylamine palla-

dacycles analogous to 2, containing chloro (instead of

bromo) and PCy₂(biaryl) (instead PPh₃) as ligands by oxi-

dative addition of 2-(2-chlorophenyl)-N-methylphenethyla-

mine to Pd(0) in the presence of the phosphine. These

metallacycles have proved to be excellent precatalysts for

C-N cross-coupling reactions.

a dihedral angle of 15.6° between the N(1)-Pd(1)-C(1)

and P(1)-Pd(1)-Br(1) planes. The chelated amine ligand

forms a six-membered metallacycle with a boat conforma-

tion. The phosphine is in trans position to the amine group,

in agreement with the well-established transphobia between

PPh₃and aryl ligands.⁴⁷These features are similar to those of

analogous complexes containing other primary phenethyla-

mine derivatives.^38,39,48,49In the crystal, two molecules of

complex 2 are connected via a 2-fold axis to form dimers

Synthesis and Structure of Monoinserted Derivatives. In

order to prepare monoinserted derivatives of the comple-

xes containing ortho-metalated primary and secondary

arylalkylamines, reactions with internal alkynes RCtCR⁰

(R=Ph, R⁰= CO₂Me, CO₂Et, Ph; R = R⁰=Me, Et)

were studied. Dilute acetone or CH₂Cl₂solutions of

PhCtCCO₂R (R=Me, Et) were carefully added dropwise

in slightly less than stoichoimetric quantities to solutions of

complex 1 or A-F (Chart 1) in the same solvent. Under these

conditions, complex 1 did not react with the alkyne, complex

F afforded complicated mixtures that we have not been able

to separate, and complexes B-E rendered mixtures of the

starting material and the corresponding di-inserted deriva-

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tive. Nevertheless, the reaction of complex

A with

ꢀ

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Arellano, M. C.; Jones, P. G. Organometallics 2002, 21, 272. (k) Vicente, J.;

PhCtCCO₂R (R=Me, Et) in a molar ratio 1:1.9 in CH₂Cl₂

afforded the complex [Pd₂{κ²(C,N)-C(Ph)dC(CO₂R)-

C₆H₄CH₂NHCH₂Ph-2}₂(μ-Br)₂] (R = Me (4a), Et (4b)), re-

sulting from insertion of one molecule of alkyne into the

Pd-aryl bond (Scheme 3). The ¹H NMR spectra of both

complexes are difficult to analyze, as they show broad and

overlapped signals, probably because dimeric transoid and

cisoid complexes 4 are formed and the metallacycles are not

rigid and can adopt different conformations. The reaction of

these dimers with PPh₃or ^tBuNC (molar ratio=1:2) afforded

the seven-membered cis-aryl-vinyl cyclopalladated complexes

[Pd{κ²(C,N)-C(Ph)dC(CO₂R)C₆H₄CH₂NHCH₂Ph-2}Br(L)]

(L=PPh₃, R=Me (5a), Et (5b); L = ^tBuNC, R = Me (6a), Et

ꢀ

Abad, J. A.; Hernandez-Mata, F. S.; Jones, P. G. J. Am. Chem. Soc. 2002,

ꢀ

124, 3848. (l) Lopez, C.; Caubet, A.; Perez, S.; Solans, X.; Font-Bardıa, M.

J. Organomet. Chem. 2003, 681, 82. (m) Crespo, M.; Granell, J.; Solans, X.;

Font-Bardia, M. J. Organomet. Chem. 2003, 681, 143. (n) Amatore, C.;

Bahsoun, A. A.; Jutand, A.; Meyer, G.; Ntepe, A. N.; Ricard, L. J. Am.

Chem. Soc. 2003, 125, 4212. (o) Rodrıguez, N.; Cuenca, A.; Ramırez de

ꢀ

Arellano, C.; Medio-Simon, M.; Peine, D.; Asensio, G. J. Org. Chem.

ꢀ

2004, 69, 8070. (p) Vicente, J.; Arcas, A.; Galvez-Lopez, M. D.; Jones, P.

G. Organometallics 2006, 25, 4247. (q) Marshall, W. J.; Grushin, V. V.

Organometallics 2003, 22, 555. (r) Ng, J. K. P.; Chen, S.; Li, Y.; Tan, G. K.;

Koh, L. L.; Leung, P. H. Inorg. Chem. 2007, 46, 5100. (s) Casas, J. M.;

Fornies, J.; Fuertes, S.; Martin, A.; Sicilia, V. Organometallics 2007, 26,

ꢀ

1674. (t) Vicente, J.; Arcas, A.; Fernandez-Hernandez, J. M.; Aullon, G.;

Bautista, D. Organometallics 2007, 26, 6155. (u) Vicente, J.; Arcas, A.;

ꢀ

Galvez-Lopez, M.-D.; Julia-Hernandez, F.; Bautista, D.; Jones, P. G.

Organometallics 2008, 27, 1582.

ꢀ

1

ꢀ

(48) Vicente, J.; Saura-Llamas, I.; Garcıa-Lopez, J. A.; Calmuschi-

(6b); Scheme 3). The H NMR spectra of the monomeric

species were easier to analyze, and in all cases, only one

regioisomer was formed.

Cula, B.; Bautista, D. Organometallics 2007, 26, 2768.

(49) Biscoe, M. R.; Fors, B. P.; Buchwald, S. L. J. Am. Chem. Soc.

2008, 130, 6686.

Article

Organometallics, Vol. 28, No. 14, 2009 4179

Scheme 3. Mono-insertion of an Alkyne into the Pd-C Bond of

Ortho-metalated Dibenzylamine

Figure 3. X-ray thermal ellipsoid plot of complex 5a (50%

probability) showing the labeling scheme (phenyl rings of

PPh₃and hydrogen atoms bonded to carbon have been omitted

Several studies of the factors governing the regiochemi-

stry of the insertions of alkynes into Pd-C bonds have

appeared.^{13-17,22,25,27,29,50-54}Electronic and steric effects have

been invoked to explain the regioselectivities observed^14,16and

the potential coordination of the alkyne substituents to the

palladium center in the transition state.^15,16,50,54Based on data

from the literature relating to catalytic and stoichiometric

reactions involving alkynes and aryl-palladium species,¹³an

empirical scale has been proposed that gives the tendency of the

CR⁰moiety of an alkyne RCtCR⁰to be attached to C_Pd.¹⁷

Accordingtothisscale,whenR=CO₂Me or CO₂Et and R⁰=Ph,

the insertion reaction must proceed in such a way that the ester

group ends up away from the palladium atom, as shown in the

crystal structures of complexes 5a and 6b (see below). This is the

normal behavior for the insertion reaction of ethyl or methyl

phenylpropiolate into the Pd-C bond of related neutral five-

membered S- or N-palladacycles.^{2,4,7,9,11,20,27,28,55}Nevertheless,

this substitution pattern can be altered when using pallada-

cycles containing weakly chelating aryl groups^22,27,51or elec-

tron-deficient palladium centers.^25,54

˚

for clarity). Selected bond lengths (A) and angles (deg): Pd(1)-

N(1) = 2.1591(13), Pd(1)-C(11) = 2.0098(16), Pd(1)-P(1)=

2.2603(4), Pd(1)-Br(1)=2.5412(2), C(2)-C(8)=1.498(2), C-

(8)-C(11)=1.343(2); C(11)-Pd(1)-N(1)=90.57(6), C(11)-Pd-

(1)-P(1)=92.32(4), N(1)-Pd(1)-Br(1)=83.35(4), P(1)-Pd(1)-

Br(1)=94.242(12).

In both complexes the carbon bearing the CO₂R group is

found adjacent to the previously metalated carbon atom. The

plane of the phenyl ring of the cyclometalated ligand forms an

angle of 71.1° (5a) or 88.5° (6b) with the coordination plane of

the palladium. In both cases, the phenyl ring bonded to the

vinyl fragment is almost perpendicular to the coordination

plane of the palladium (84.3°, 5a; 83.7°, 6b). Only a few crystal

structures of similar complexes have been solved.^22,54

Each molecule of complex 6b is connected to two other

molecules through hydrogen bonds, giving zigzag chains

along the b axis (Figure 5). No such interactions are observed

for complex 5a, which must be due to the steric hindrance

of PPh₃.

The crystal structures of complexes 5a and 6b have

been solved by X-ray diffraction studies (Figures 3 and 4).

Complex 6b shows an almost perfect square-planar environ-

ment for the palladium atom (mean deviation from the plane

The reaction of complex A with other internal alkynes (i.e.,

MeCtCMe, EtCtCEt) under similar experimental condi-

tions to those described above led to mixtures of products

where the starting material and di-inserted species were

present (by ¹H NMR). This is the normal behavior for most

ortho-metalated complexes: when electron-rich alkynes are

used, only di-inserted products are obtained because the

second insertion is faster than the first,^{1,6,22,41,44,56}whereas

with PhCtCPh and other alkynes containing electron-with-

drawing substituents such as CF₃or CO₂R, it is possible to

isolate the monoinsertion derivatives.^{1,4,9,19-22,27,31,37,52,54,55,57}

It is reasonable to assume that the presence of the electron-

withdrawing group next to the aryl ring in the seven-membered

palladacycle may retard the insertion of the second alkyne.⁵³

˚

0.028 A), while in 5a the palladium atom is in a slightly dis-

torted square-planar environment (mean deviation from the

˚

plane 0.086 A) with a dihedral angle of 7.6° between the

N(1)-Pd(1)-C(11) and P(1)-Pd(1)-Br(1) planes. The se-

ven-membered rings adopt a boat conformation; the dihe-

dral angle between the planes defined by Pd(1)-N(1)-C(11)

(5a) or Pd(1)-N(1)-C(10) (6b) and the four remaining

atoms of the palladacycle (C(7)-C(1)-C(2)-C(8) for 5a

and C(7)-C(1)-C(2)-C(9) for 6b) is 72.8° (5a) or 83.8° (6b).

(50) Arcadi, A.; Cacchi, S.; Marinelli, F. Tetrahedron 1985, 41, 5121.

(51) Maassarani, F.; Pfeffer, M.; Le Borgne, G. Organometallics

1990, 9, 3003.

ꢀ

(56) Perez, S.; Lopez, C.; Caubet, A.; Pawezczyk, A.; Solans, X.; M.,

F.-B. Organometallics 2003, 22, 2396.

(52) Spencer, J.; Pfeffer, M.; Kyritsakas, N.; Fischer, J. Organome-

tallics 1995, 14, 2214.

(57) (a) Jarvis, A. C.; W. Kemmitt, R. D. W.; Kimura, B. Y.; Russell,

D. R.; Tucker, P. A. J. Organomet. Chem. 1974, 66, C53. (b) Dehand, J.;

Mutet, C.; Pfeffer, M. J. Organomet. Chem. 1981, 209, 255. (c) Arlen, C.;

Pfeffer, M.; Bars, O.; Le Borgne, G. J. Chem. Soc., Dalton Trans. 1986,

359. (d) Zhao, G.; Wang, Q.-G.; Mak, T. C. W. J. Organomet. Chem.

1999, 574, 311. (e) Knorr, M.; Jourdain, I.; Braunstein, P.; Strohmann,

C.; Tiripicchio, A.; Ugozzoli, F. Dalton Trans. 2006, 5248.

ꢀ

(53) Bosque, R.; Benito, M.; Lopez, C. New J. Chem. 2001, 25, 827.

(54) Kelly, A. E.; Macgregor, S. A.; Willis, A. C.; Nelson, J. H.;

Wenger, E. Inorg. Chim. Acta 2003, 352, 79.

(55) Pereira, M. T.; Pfeffer, M.; Rotteveel, M. A. J. Organomet.

Chem. 1989, 375, 139.

4180 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

Figure 4. X-ray thermal ellipsoid plot of complex 6b (50%

probability) showing the labeling scheme (hydrogen atoms

bonded to carbon have been omitted for clarity). Selected bond

˚

lengths (A) and angles (deg): Pd(1)-N(1)=2.0950(19), Pd(1)-C-

Figure 5. X-ray packing view of complex 6b showing the chains

along the b axis formed through hydrogen bond interactions.

Only atoms involved in the hydrogen bonding have been

labeled. Details (including symmetry operators) are given in

the Supporting Information.

(10)=2.021(2), Pd(1)-C(11)=1.933(2), Pd(1)-Br(1)=2.5162(3),

C(2)-C(9) = 1.492(3), C(9)-C(10) = 1.328(3); C(11)-Pd(1)-

C(10)=87.37(9), C(10)-Pd(1)-N(1) = 92.74(8), C(11)-Pd(1)-

Br(1) = 92.78(7), N(1)-Pd(1)-Br(1)=86.94(6).

However, A reacted with PhCtCPh (1:1) to give the starting

material and di-inserted species. This behavior is similar to that

described for ortho-palladated N,N-dimethylbenzylamine.¹

Synthesis, Structure, and Reactivity toward CO of Di-

inserted Derivatives. Ortho-metalated complexes [Pd₂{κ²(C,

N)-C₆H₃CH₂NH₂-2,X-5}₂(μ-Br)₂] (X = Cl (C), F (D), NO₂

(E)) react with an excess of RCtCR (R=Et, Ph; molar

ratio=1:6-10) to give the complexes resulting from a double

insertion of the alkyne into the Pd-C bond [Pd{κ²(C,N)-C-

(R)dC(R)C(R)dC(R)C₆H₃CH₂NH₂-2,X-5}Br] (X = Cl,

R=Et (7a), Ph (7b); X = F, R = Et (8a), Ph (8b); X =

NO₂, R=Ph (9); Scheme 4). Di-insertion reactions using

complex A as starting material have been previously reported

by us.⁴²When no excess of the alkyne was used, unreacted

cyclometalated complexes were recovered along with the di-

inserted complexes. The reaction conditions depended on

both the nature of the alkyne and the substituent on the

phenyl ring. Thus, when X = OMe, the reaction with 3-

hexyne occurs in CH₂Cl₂at room temperature and is com-

plete within 8 h (by ¹H NMR), although the di-inserted

product could not be isolated in pure form, as it decomposes

in solution. When X=Cl, F, the insertion of 3-hexyne

required heating the mixture in acetone for 6 h, while the

insertion of diphenylacetylene has to be carried out in

refluxing acetonitrile for 9-10 h. Finally, when X=NO₂,

only insertion of 3-hexyne was observed after heating the

reaction mixture in acetonitrile at 110 °C in a Carius tube.

The reported insertion reaction of two molecules of RCtCR

(R=Et or Ph) in complex A was complete after stirring a

1:6-8 mixture of the ortho-metalated complex and the

alkyne for 6 h in CH₂Cl₂at room temperature.⁴²

Scheme 4. Insertion of Two Molecules of Alkyne into the Pd-C

Bond of Ortho-metalated Primary Benzylamines

of the aryl group to the coordinated alkyne. The rate of this

process increases when increasing the electrophilicity of the

alkyne and the nucleophilicity of the carbon atom bonded to

Pd(II). Thus, electron-releasing groups on the aromatic ring

favor the reaction, while electron-withdrawing substituents

decrease the reaction rate.³⁵Steric factors are also involved,

as small substituents on the alkyne accelerate the reaction.^15,35

These trends explain our experimental observations: (1) the

synthesis of derivatives of 4-NO₂-benzylamine demands high

temperatures and long reaction times, while those with ortho-

metalated 4-OMe-benzylamine occur at room temperature;

(2) the insertion of 3-hexyne requires milder conditions than

diphenylacetylene.

Di-inserted complexes of cyclopalladated secondary^6,42

and tertiary benzylamines are known,^{1,4,6,7,28,35,51,58}but, as

The results observed for cyclopalladated primary benzyl-

amines are analogous to those found for tertiary benzyl-

amines and agree with the proposed mechanism for these

di-insertion reactions.³⁵The rate-determining step is the

formation of the monoinsertion derivative, which requires

the η²-coordination of the alkyne to Pd(II) and the migration

(58) (a) Pfeffer, M.; Rotteveel, M. A.; Sutter, J.-P.; De Cian, A.;

Fischer, J. J. Organomet. Chem. 1989, 371, C21. (b) Sutter, J.-P.; Pfeffer,

M.; De Cian, A.; Fischer, J. Organometallics 1992, 11, 386.

Article

Organometallics, Vol. 28, No. 14, 2009 4181

Figure 7. X-ray thermal ellipsoid plot of complex 7b 3DMSO

(50% probability) showing the labeling scheme (solvent mole-

cules and hydrogen atoms bonded to carbon have been omit-

3

˚

ted for clarity). Selected bond lengths (A) and angles (deg):

Pd-N(1)=2.137(2), Pd-Br=2.4449(3), Pd-C(1)=2.009(2),

Pd-C(3) = 2.205(2), Pd-C(4) =2.217(2), Pd-X = 2.096, C

(1)-C(2)=1.338(3), C(3)-C(4)=1.407(3); C(1)-Pd-Br=97.12(6),

N(1)-Pd-Br = 88.99(5), N(1)-Pd-X = 98.1, C(1)-Pd-

X = 75.6, C(1)-Pd-C(3)=65.70(8), C(1)-Pd-C(4)=86.53(8),

C(3)-Pd-C(4)=37.11(8). X represents the midpoint of the

double bond C(3)-C(4).

Figure 6. X-ray thermal ellipsoid plot of complex 7a (50%

probability) showing the labeling scheme (hydrogen atoms

bonded to carbon have been omitted for clarity). Selected

˚

bond lengths (A) and angles (deg): Pd-N(1)=2.175(2), Pd-

Br=2.4621(6), Pd-C(1)=2.006(3), Pd-C(3)=2.168(2), Pd-

C(4)=2.186(3), Pd-X=2.06, C(1)-C(2) = 1.326(4), C(3)-

C(4)=1.410(4); C(1)-Pd-Br=96.89(8), N(1)-Pd-Br=88.30(6),

N(1)-Pd-X=99.5, C(1)-Pd-X=74.9, C(1)-Pd-C(3)=65.47

(11), C(1)-Pd-C(4)=85.48(11), C(3)-Pd-C(4) = 37.79(10). X

represents the midpoint of the double bond C(3)-C(4).

stated in the Introduction, the only precedent for di-insertion

of alkynes into the Pd-C bond of complexes containing

primary benzylamines was reported by us.⁴¹Albert et al.

have reported a similar reaction with cyclometalated 2-

benzylpyridine.⁵⁹

We carried out several attempts to obtain di-inserted

derivatives from ortho-metalated phenethylamines (1 and

F; Chart 1) and 2-butyne, 3-hexyne, or diphenylacetylene.

In all cases, uncharacterized mixtures were obtained. Start-

ing from a six-membered palladacycle, insertion of two

molecules of alkyne must afford a 10-membered vinyl-palla-

dated ring, which is not stable and may suffer various

rearrangements.⁷

The molecular structures of complexes 7a, 7b 3DMSO,

3

Figure 8. X-ray thermal ellipsoid plot of complex 9 (30%

probability) showing the labeling scheme (hydrogen atoms

bonded to carbon have been omitted for clarity). Selec-

and 9 have been solved by X-ray diffraction (Figures 6, 7 and

8). The atoms Br, N, and C(1), together with the midpoint of

the C(3)-C(4) double bond, form a distorted square plane

around the palladium atom. The C(3)-C(4) bond (1.410(4)

˚

ted bond lengths (A) and angles (deg): Pd-N(1)=2.172(3),

Pd-Br=2.4684(5), Pd-C(1) =2.005(3), Pd-C(3)=2.169(3),

Pd-C(4) = 2.196(3), Pd-X=2.066, C(1)-C(2) = 1.317(4),

C(3)-C(4) = 1.407(4); C(1)-Pd-Br = 96.64(9), N(1)-Pd-

Br=89.19(9), N(1)-Pd-X = 99.1, C(1)-Pd-X = 74.7, C(1)-

Pd-C(3)=65.34(12), C(1)-Pd-C(4)=85.13(11), C(3)-Pd-

C(4)=37.60(10). X represents the midpoint of the double bond

C(3)-C(4).

˚

A, 7a; 1.407(3), 7b 3DMSO; 1.407(4) A, 9) is slightly longer

3

˚

than the C(1)-C(2) bond (1.326(4) A, 7a; 1.338(3),

˚

7b 3DMSO; 1.317(4) A, 9) because of coordination to the

3

palladium atom. The C(3)-C(4) double bond forms an

angle of 59.2° (7a), 58.5° (7b 3DMSO), or 59.1° (9) with the

palladium coordination plane. The ethyl (7a, 9) or phenyl

3

(7b 3DMSO) substituents at the C(1)-C(2) double bond are

3

mutually cis, and those at the C(3)-C(4) bond are mutually

trans. All di-inserted derivatives containing cyclometalated

amines show this [Pd]-cis-C(R)dC(R)-trans-C(R)dC(R)-aryl

geometry,^{1,6,35,41,58,60}which requires the isomerization of the

first inserted alkyne.^7,35,44This arrangement reduces the steric

hindrance between the substituents. Notably, the distances N-

˚

(1)-Pd (2.175(2) A, 7a; 2.137(2), 7b 3DMSO; 2.172(9) A, 9)

3

are shorter than the Pd-N distances found for similar pallada-

˚

cycles containing tertiary amines (range: 2.209-2.247 A;

average value: 2.228 A), which may serve as evidence of a

(59) Albert, J.; D’Andrea, L.; Granell, J.; Zafrilla, J.; Font-Bardia,

M.; Solans, X. J. Organomet. Chem. 2007, 692, 4895.

(60) Tomita, K.; Caires, A. C.; de Lucca Neto, V. A.; Mauro, A. E.

Acta Crystallogr., Sect. C 1994, 50, 1872.

˚

stronger coordination of the primary amine group to the

palladium center.

4182 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

Figure 9. X-ray packing view of complex 7a showing the dimer

formed through N-H(2) Br(A) hydrogen bonds (A: -x+2,

3 3 3

Figure 10. X-ray packing view of complex 9 showing the dimers

formed through N(1A)-H(0BA) Br(B) hydrogen bonds (B:

˚

-y+1, -z; N Br(A) 3.557(3) A, H(2) Br(A) 2.65 A, N-H-

3 3 3

(2) Br(A) 167.5°). Only Pd and atoms involved in the hydro-

gen bonding have been labeled.

3 3 3

˚

-x+2, -y+1, -z; N(1A) Br(B) 3.624(4) A, H(0BA) Br-

3 3 3

˚

(B) 2.74(4) A, N(1A)-H(0BA) Br(B) 177(3)°). Only Pd and

atoms involved in the hydrogen bonding have been labeled.

3 3 3

In complexes 7a and 9, the discrete molecules are asso-

ciated through a pair of hydrogen bonds (between the

bromine atom and one hydrogen of the amine group)

to give inversion-symmetric dimers (Figures 9 and 10).

bond of alkyl-, π-allyl-, and arylpalladium complexes are

well-studied reactions, but those leading to complexes 13 and

14 have few precedents.^6,42

The crystal structure of complex 14a has been solved by X-

ray diffraction studies (Figure 11). Coordination around the

palladium atom can be described as a distorted trigonal

bipyramid, with C(11) and N(1) in the axial positions (angle

C(11)-Pd(1)-N(1) 175.30(15)°) and Br(1), Br(1A), and the

midpoint of the double bond C(7)-C(8) (represented as X)

occupying equatorial sites (mean deviation from the plane

In complex 7b 3DMSO, the molecules of the di-inserted

3

complex are associated through hydrogen bonds with

the DMSO molecules, move giving a three-dimensional

network.

Reaction of complex A with nonsymmetrical alkynes

PhCtCCO₂R in a 1:6 (R=Me) or 1:7 (R=Et) molar ratio or

Dwith PhCtCCO₂Et in a 1:6 molar ratio (Scheme 5) afforded a

mixture of the di-inserted head-to-tail [Pd{κ²(C,N)-C(Ph)dC

(CO₂Me)C(Ph)dC(CO₂R)C₆H₄CH₂NHCH₂Ph-2}Br] (R=Me

(10a), Et (10a)) or [Pd{κ²(C,N)-C(Ph)dC(CO₂Me)C(Ph)dC

(CO₂R)C₆H₃CH₂NH₂-2,F-5}Br] (12a) and tail-to-tail

isomers [Pd{κ²(C,N)-C(CO₂Me)dC(Ph)C(Ph)dC(CO₂R)C₆H₄-

CH₂NHCH₂Ph-2}Br] (R= Me (10b), Et (11b))or [Pd{κ²(C,N)-

C(CO₂Me)dC(Ph)C(Ph)dC(CO₂R)C₆H₃CH₂NH₂-2,F-5}Br]

(12b). Their ¹H NMR spectra showed the presence of approxi-

mately equal amounts of the two isomers of 10 and 11 and a 1:3

molar ratio of isomers 12a:12b. A similar behavior has been

reported for ortho-metalated N,N-dimethylbenzylamine.⁴At-

tempts to separate the isomers by fractional crystallization or by

chromatography were unsuccessful. Because the monoinsertion

of PhCtCCO₂R is regiospecific, the two isomers obtained in the

di-insertion reaction must arise from a nonselective insertion of

the second molecule of the alkyne.²²

˚

Pd(1)-Br(1)-Br(1A)-X 0.0047 A). The Pd(1)-Br(1A)

(2.5967(5) A) bond is longer than those found in four-

coordinated complexes 7a and 9 (2.4621(6) and 2.4684(5)

˚

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Soc., Dalton Trans. 1998, 1775. (o) Campora, J.; Graiff, C.; Palma, P.;

Carmona, E.; Tiripicchio, A. Inorg. Chim. Acta 1998, 269, 191.

(p) Kayaki, Y.; Shimizu, I.; Yamamoto, A. Bull. Chem. Soc. Jpn.

Complexes 7a,b and 8a,b insert CO into the Pd-C bond

to give the 10-membered palladacycles [Pd₂{κ²(C,N)-C(O)-

C(R)dC(R)C(R)dC(R)C₆H₃CH₂NH₂-2,X-5}₂(μ-Br)₂] (X=

Cl, R=Et (13a), Ph (13b); X=F, R=Et (14a), Ph (14b);

Scheme 6).

The IR spectra of complexes 13 and 14 show a ν(CO) band

in the range 1674-1688 cm^-1, confirming the presence of

inserted CO. Their ¹H NMR spectra are similar to those of

the parent complexes 7a,b and 8a,b, but the signals corre-

sponding to the NH₂group appear at higher frequencies

(Δδ = 0.8-1.3 ppm). Insertion of CO^18,61into the Pd-C

ꢀ

1997, 70, 917. (q) Gutierrez, E.; Nicasio, M. C.; Paneque, M.; Ruiz,

C.; Salazar, V. J. Organomet. Chem. 1997, 549, 167. (r) Dupont, J.;

Pfeffer, M. J. Chem. Soc., Dalton Trans. 1990, 3193. (s) Hoare, J. L.;

Cavell, K. J.; Hecker, R.; Skelton, B. W.; White, A. H. J. Chem. Soc.,

Dalton Trans. 1996, 2197. (t) Yamamoto, A. J. Chem. Soc., Dalton

ꢀ

Trans. 1999, 1027. (u) Vicente, J.; Saura-Llamas, I.; Garcıa-Lopez, J.-

A.; Bautista, D. Organometallics 2009, 28, 448.

Article

Scheme 5. Insertion of Two Molecules of Nonsymmetrical

Organometallics, Vol. 28, No. 14, 2009 4183

Alkynes into the Pd-C Bond of Ortho-metalated Primary and

Secondary Benzylamines

Figure 11. X-ray thermal ellipsoid plot of complex 14a 2DMSO

(50% probability) showing the labeling scheme (solvent molecules

and hydrogen atoms bonded to carbon have been omitted for

3

˚

clarity). Selected bond lengths (A) and angles (deg): Pd(1)-N(1)=

2.183(4), Pd(1)-C(11)=1.979(4), Pd(1)-Br(1A) = 2.5967(5), Pd-

Br(1)=2.9128(5), Pd(1)-C(7)=2.159(4), Pd(1)-C(8) = 2.136(4),

Pd(1)-X=2.025, C(7)-C(8) = 1.435(5), C(9)-C(10) = 1.342(5);

Br(1A)-Pd(1)-Br(1) = 85.247(15), Br(1A)-Pd(1)-X = 140.4,

Br(1)-Pd(1)-X=134.3, N(1)-Pd(1)-Br(1)=78.95(9), N(1)-

Pd(1)-Br(1A) = 88.38(9), N(1)-Pd(1)-X = 97.5, C(11)-Pd(1)-

Br(1)=97.11(12), C(11)-Pd(1)-Br(1A)=88.74(11), C(11)-Pd(1)-

X = 87.1. X represents the midpoint of the double bond C(7)-C(8).

Scheme 6. Reactions of Di-inserted Derivatives with CO

nated palladium(II) complexes.⁶³The C(7)-C(8) double

bond forms an angle of 11.0° with the equatorial coordina-

tion plane of palladium (mean deviation from the plane

˚

Pd(1)-Br(1A)-Br(1)-X 0.005 A). The distance Pd-X

(2.025 A) is slightly shorter than the homologous distance

˚

in complexes 7a and 9 (2.06 and 2.066 A, respectively), which

could be attributed to a stronger π-back-donation from the

metal center to the olefin fragment in complex 14a. Corre-

spondingly, the coordinated double bond in 14a (C(7)-C(8)

˚

1.435(5) A) is slightly (Δd = 0.025 A), although significantly

(Δd ≈ 3(σ₁+ σ₂)), longer than the analogous bond in

˚

complex 7a (C(3)-C(4) 1.410(4) A).

The structural features of complex 14a contrast with those

found in related complexes [Pd{κ²(C,N)-C(O)C(Et)dC(Et)-

C(Et)dC(Et)C₆H₄CH₂NMe₂-2}Cl]⁶and [Pd{κ²(C,N)-C(O)-

C(Me)dC(Me)C(Me)dC(Me)C₆H₄CH₂NHCH₂Ph-2}Br],⁴²

which are monomeric, and in which the Pd(II) shows the usual

square-planar environment. The absence of substituents at the

nitrogen atom coordinated to palladium in complex 14a seems

essential to allow the formation of the bromo bridge.

All the reported five-coordinated olefin complexes of

palladium⁶⁴have a trigonal-bipyramidal geometry with the

alkene in an equatorial position.^64,65In these complexes, the

˚

A, respectively), and the distance Pd(1)-Br(1) (2.9128(5) A)

is even longer, but below the sum of the van der Waals radii

62

˚

(3.4-3.6 A). Similar Pd-Br distances (2.90-3.02 A) have

been reported for distorted square-pyramidal five-coordi-

(64) Albano, V. G.; Natile, G.; Panunzi, A. Coord. Chem. Rev. 1994,

133, 67.

(62) Bondi, A. J. Phys. Chem. 1964, 68, 441.

(65) (a) Desmarais, N.; Adamo, C.; Panunzi, B.; Barone, V.;

Giovannitti, B. Inorg. Chim. Acta 1995, 238, 159. (b) Burger, P.; Baumeister,

J. M. J. Organomet. Chem. 1999, 575, 214. (c) Di Bianca, F.; Bandoli, G.;

Dolmella, A.; Antonaroli, S.; Crociani, B. J. Chem. Soc., Dalton Trans. 2002,

212. (d) Binotti, B.; Bellachioma, G.; Cardaci, G.; Macchioni, A.; Zuccaccia,

C.; Foresti, E.; Sabatino, P. Organometallics 2002, 21, 346.

(63) (a) Collier, J. W.; Mann, F. G.; Watson, D. G.; Watson, H. R. J.

Chem. Soc. 1964, 1803. (b) Chui, K. M.; Powell, H. M. J. Chem. Soc.,

Dalton Trans. 1974, 1879. (c) Chui, K. M.; Powell, H. M. J. Chem. Soc.,

Dalton Trans. 1974, 2117. (d) Sevillano, P.; Habtemariam, A.;

~

Castineiras, A.; Garcıa, M. E.; Sadler, P. J. Polyhedron 1999, 18, 383.

4184 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

Scheme 7. Synthesis of Tri-inserted Derivatives with DMAD

Figure 12. X-ray thermal ellipsoid plot of complex 18 (50%

probability) showing the labeling scheme (hydrogen atoms

bonded to carbon have been omitted and noncoordinated

CO₂Me groups have been represented by one carbon atom for

other two equatorial sites are usually occupied by a chelating

ligand, which probably is essential in order to isolate the five-

coordinated complex. Complex 14a is (1) the first five-

coordinated alkene complex of Pd(II) with two monodentate

ligands at the equatorial positions and (2) the first trigonal-

bipyramidal complex of Pd(II) with two halogen-bridging

ligands.

˚

clarity). Selected bond lengths (A) and angles (deg): Pd-N =

2.029(3), Pd-Br = 2.4801(6), Pd-O(4) = 2.073(3), Pd-C(9) =

2.071(4), O(4)-C(86) = 1.223(5); N-Pd-C(9) = 93.22(14), C-

(9)-Pd-O(4) = 82.99(13), O(4)-Pd-Br = 93.17(8), N-Pd-

Br = 91.04(10).

For complexes 13a,b and 14b in the solid state we propose

similar structures to that of 14a, as all of them derive from

ortho-metalated primary amines. However, we cannot rule

out a normal square-planar environment in solution

(Scheme 6).

Synthesis and Structure of Tri-inserted Derivatives. The

reaction of dimethyl acetylenedicarboxylate (DMAD) with

the halogen-bridged dinuclear ortho-palladated complexes

containing primary or secondary arylalkylamines (1, A-G;

Scheme 7) gave, in all cases, tri-inserted products containing

the same C₅cyclopentadienyl unit described for analogous

reactions with other cyclopalladated amines.^{7,22,33,41,43,44}

Most reactions were carried out in CH₂Cl₂, at room

temperature, using an excess of alkyne (molar ratios=7-

16:1) and reaction times of 18-72 h. Only complex 21 was

isolated after stirring 1 and the alkyne in refluxing acetone

for 10 h (Scheme 7).

The ¹H NMR and ¹³C NMR spectra of complexes 15-21

showed six resonances corresponding to the OMe groups,

which clearly indicates that tri-insertion of the alkyne has

taken place.

Figure 13. X-ray thermal ellipsoid plot of complex 21 (50%

probability) showing the labeling scheme (hydrogen atoms

bonded to carbon have been omitted and noncoordinated

CO₂Me substituents have been represented by one car-

The crystal structures of complexes 18 and 21 have been

solved by X-ray diffraction (Figures 12 and 13). The palla-

dium atom shows a distorted square-planar geometry (mean

˚

bon atom for clarity). Selected bond lengths (A) and

angles (deg): Pd(1)-N(1)=2.041(3), Pd(1)-Br(1)=2.4894(4),

Pd(1)-O(1) =2.071(2), Pd(1)-C(1) =2.065(3), O(1)-C(3)=

1.227(4); N(1)-Pd(1)-C(1)=89.53(12), C(1)-Pd(1)-O(1)=

83.09(10), O(1)-Pd(1)-Br(1)=90.72(6), N(1)-Pd(1)-Br(1)=

96.70(8).

˚

deviation from the plane: Pd-Br-O(4)-C(9)-N 0.100 A,

˚

18; Pd(1)-Br(1)-O(1)-C(1)-N(1) 0.025 A, 21). Both com-

plexes contain a tridentate ligand, which is bonded to Pd

through the nitrogen atom of the amine group, the carbon

C(9) (18) or C(1) (21), and the oxygen atom O(4) (18) or O(1)

(21) of one carboxylate group. The fourth coordination site is

occupied in both cases by a bromo ligand. This arrangement

defines two metallacycles containing five and six (18) or

seven (21) members. A cyclopentadiene ring is connected to

the five-membered palladacycle by C(10) (18) or C(2) (21).

The six-membered palladacycle of complex 18 has an envel-

ope conformation, while the seven-membered ring of com-

plex 21 adopts a boat conformation. In both complexes, the

five-membered palladacycle is not planar, the atom C(9) (18)

˚

or C(1) (21) lying significantly (0.651 A, 18; 0.515 A, 21) out

of the least-squares plane defined by the remaining four

atoms of the ring (mean deviation: 0.038, 18; 0.015, 21).

These features are similar to those previously reported for

other tri-inserted derivatives.^22,43,44Additionally, in com-

plex 21 there is a weak interaction between Pd(1) and the

˚

methyl C(12); the distance Pd(1)-C(12) is 2.554 A and the

angle C(12)-C(1)-Pd(1) is 90.1°. Similar interactions have

Article

Organometallics, Vol. 28, No. 14, 2009 4185

Scheme 9. Insertion of Three Molecules of 2-Butyne into the

Pd-C Bond of Ortho-metalated Dibenzylamine

Figure 14. X-ray packing of complex 21 showing the hydrogen

bond interactions (only atoms involved in the hydrogen bonding

have been labeled). Details (including symmetry operators) are

given in the Supporting Information.

Scheme 8. Reactivity of Tri-inserted Derivatives Containing

DMAD

layers (Figure 14). Similar interactions are not observed for

complex 18.

We have carried out several reactions in order to obtain

organic derivatives from the tri-inserted derivatives. For

example, complex 18 was heated in refluxing ClPh and

treated with an excess of PPh₃or pyridine to promote a

reductive elimination. In both cases, although decomposi-

tion to Pd(0) took place, complicated mixtures were obtained

from which no pure organic compounds could be isolated. In

order to increase the reactivity of the tri-inserted com-

plexes,³⁴we prepared cationic derivatives. Thus, the reaction

of complex 18 with TlOTf (1:1 molar ratio) in acetone

afforded the aquo complex [Pd{κ³(O,C,N)-OdC(OMe)-

{C₅(CO₂Me)₄}C(CO₂Me)C₆H₄CH₂NHCH₂Ph-2}(H₂O)]-

OTf (22; Scheme 8). Other palladium aquo complexes have been

obtained by this method.⁶⁶Complex 22 reacts with pyridine (py)

to give [Pd{κ³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C(CO₂Me)-

C₆H₄CH₂NH-CH₂Ph-2}(py)]OTf (23; Scheme 8). Again, all

attempts to obtain organic derivatives by thermal decomposition

of 22 or 23 were unsuccessful.

The halogen-bridged ortho-metalated complexes were

also treated with an excess of 2-butyne in an attempt to

obtain tri-insertion products, but only A reacted after a long

period of time (72 h), giving 24 along with metallic palladium

(Scheme 9). This result is unusual because only a few neutral

ortho-metalated complexes react with electron-rich alkynes,

such as 2-butyne or 3-hexyne, to give tri-inserted products

and, in addition, they decompose quickly to give metallic

palladium and organic derivatives.^3,44Therefore, A is the

only neutral cyclopalladated compound giving an isolable

complex of Pd(II) derived from a tri-inserted process using

an electron-rich alkyne. In addition, the nature of the

also been observed for other tri-inserted derivatives contain-

ing DMAD,⁴³although they are not present in complex 18.

In complex 21, the molecules are associated through

hydrogen bonds between the oxygen atom of a CO

group and one hydrogen of the ortho-metalated ring to give

(66) Vicente, J.; Arcas, A. Coord. Chem. Rev. 2005, 249, 1135.

4186 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

Scheme 10. Insertion of Three Molecules of 2-Butyne into the

Pd-C Bond of Ortho-metalated Phentermine

product is also unprecedented: it involves a methyl C-H

activation and a disproportionation process.

Insertion reactions of alkynes into the Pd-C bond of

palladacycles are facilitated by using cationic derivatives

as starting materials.^{4,12,13,17,22,34,67}Thus, reaction of com-

plex G with TlOTf and MeCtCMe (molar ratio = 1:2:6.5,

room temperature, 24 h) afforded the tri-inserted deri-

vative 25 (Scheme 10). The only isolated and characterized

complex of this type is the product resulting from the

reaction of EtCtCEt with cyclopalladated 8-methyl-

quinoline.⁶⁸

Figure 15. X-ray thermal ellipsoid plot of complex 24

(50% probability) showing the labeling scheme (hydrogen

atoms bonded to carbon have been omitted for clarity).

Selected bond lengths (A) and angles (deg): Pd-N=2.065(5),

Pd-Br=2.4321(7); N-Pd-Br=87.92(14), N-Pd-Br(A) =

92.08(14).

˚

To explain the unprecedented formation of 24 (Scheme 9),

we assume (1) the insertion of three molecules of alkyne into

the Pd-C bond followed by an internal cyclization to give I

through a process similar to that observed with DMAD or

proposed for the palladium-catalyzed cyclotrimerization of

acetylenes,^30,69or the synthesis of alkenes from N-pallada-

cycles and 2-butyne or 3-hexyne;^3,6,44(2) a β-hydrogen

elimination to give the η²-olefin hydrido complex II; and

(3) a dimerization process to give III, which disproportion-

ates to give Pd(0), H₂, and 24. An ab initio MO study

revealed that the β-hydrogen elimination to give a hydrido

complex such as II occurs through a CH_MePd agostic

3 3 3

interaction.⁷⁰The cationic nature of 25 probably helps the

coordination of the cyclopentadiene group, preventing the

formation of this agostic interaction and the β-hydrogen

elimination. Nevertheless, the course of our reaction is

atypical because in all other reported cases, the hydrido-Pd-

(II) complex formed after the β-hydrogen elimination de-

composes to give Pd(0), HX, and the free ligand.^3,6,30,44,69

The great stability of the N-Pd bond must play a crucial role

in such an unprecedented behavior. The disproportionation

step is similar to that which we observed in the decomposi-

tion of [Pd{C(dNXy)C₆H₄CH₂NH₂-2}Br(CNXy)] to give

[PdBr₂{2-(XyNH)isoindole}₂], Pd(0), and H₂,⁷¹or in the

halogenation of [Pd₂(κ²(C,N)-C₆H₄CH₂CMe₂NH₂-2)₂-

(μ-Cl)₂] or (S,S)-[Pd₂{κ²(C,N)-C₈H₅NCH₂CH(CO₂Me)

NH₂-2}₂(μ-Cl)₂] giving [PdX₂(L-X⁰)₂] (L-X⁰= orthohaloge-

nated primary amine) and PdX⁰₂.^48,72

(67) Yagyu, T.; Osakada, K.; Brookhart, M. Organometallics 2000,

19, 2125.

(68) Rheingold, A. L.; Wu, G. Z.; Heck, R. F. Inorg. Chim. Acta 1987,

131, 147.

(69) Maitlis, P. M. Pure Appl. Chem. 1973, 33, 489.

(70) Koga, N.; Obara, S.; Kitaura, K.; Morokuma, K. J. Am. Chem.

Soc. 1985, 107, 7109.

Figure 16. X-ray packing view of complex 24 showing the voids

3

(ca. 208 A ) forming channels along the b axis (red bromine, blue

nitrogen, dark green palladium, gray carbon, and white hydro-

gen atoms).

˚

€

(71) Vicente, J.; Saura-Llamas, I.; Grunwald, C.; Alcaraz, C.; Jones,

The crystal structure of complex 24 has been determined

by X-ray diffraction studies (Figure 15), showing the palla-

dium atom coordinated to two bromine and two nitrogen

P. G.; Bautista, D. Organometallics 2002, 21, 3587.

(72) Vicente, J.; Saura-Llamas, I.; Bautista, D. Organometallics 2005,

24, 6001.

Article

Organometallics, Vol. 28, No. 14, 2009 4187

feature for bis(amino)-dihalopalladium(II) complexes.^72,73

3

Voids of 208.0 A were found arranged into channels along

˚

the b axis (Figure 16). No hydrogen bond acceptor was found

for the N-H group.

The molecular structure of complex 25 has been deter-

mined by X-ray diffraction studies (Figure 17). The palla-

dium atom is bonded to a water molecule and a new

tridentate ligand through N(1), C(22), and the midpoint of

the C(12)-C(21) double bond of a C₅Me₅unit, in a distorted

square-planar geometry. The Pd-C(12) and Pd-C(21)

lengths are appreciably different (2.1660(19) and 2.3340-

˚

(19) A), and the C(12)-C(21) bond (1.388(3) A) is slightly

˚

longer than C(14)-C(15) (1.346(3) A) because of coordina-

tion to the palladium atom. These features are similar to

those found for a similar complex described by Rheingold

et al.⁶⁸The cationic units are connected to the triflate groups

through hydrogen bonds (each molecule has three interac-

tions with two different triflates), generating zigzag chains

along the b axis (Figure 18).⁶⁶

Figure 17. X-ray thermal ellipsoid plot of the cation of com-

plex 25 (50% probability) showing the labeling scheme (hydro-

gen atoms bonded to carbon have been omitted for clarity).

˚

Selected bond lengths (A) and angles (deg): Pd(1)-N(1)=2.1221-

(17), Pd(1)-O(1)=2.2420(15), Pd(1)-C(22)=2.0355(19), Pd-

(1)-C(12)=2.1660(19), Pd(1)-C(21)=2.3340(19), Pd(1)-X=

2.142, C(12)-C(21)=1.388(3), C(14)-C(15)=1.346(3); C(22)-

Pd(1)-N(1)=92.11(7), N(1)-Pd(1)-O(1)=89.29(6), O(1)-Pd-

(1)-X = 102.3, C(22)-Pd(1)-X=79.3, C(12)-Pd(1)-C(21)=

35.67(7). X represents the midpoint of the double bond C(12)-

C(21).

Conclusion

A facile synthesis of the first complexes containing ortho-

metalated secondary phenethylamine through metalation is

reported. Insertion reactions of alkynes into the Pd-C bond

of cyclometalated complexes containing primary and sec-

ondary benzyl and phenethylamines allow the synthesis of

enlarged palladacycles containing one, two, or three mole-

cules of alkyne per palladium atom. These include the first

palladacycles derived from insertion of one molecule of

alkyne into the Pd-C bond of a secondary benzylamine.

The reaction conditions, the size of the palladacycle, and the

electronic and steric properties of the alkyne determined the

isolated product. A considerable variety of these complexes

have been prepared, most of which show structural features

analogous to those described for similar compounds con-

taining tertiary amines, although our complexes exhibit a

greater stability. Especially remarkable is the synthesis of

the new tri-inserted derivatives, which are prepared in quite

mild conditions and include examples of all the types known

for these kinds of complexes. Particularly relevant is the

unprecedented formation of a Pd(II) complex containing a

ligand that results from an internal cyclization process and a

β-hydrogen elimination. An interesting bromo-bridged pen-

tacoordinated Pd(II) complex, in which the palladium atom

shows a TBP geometry, is obtained by insertion of CO into

the Pd-C bond of a di-inserted derivative.

Experimental Section

Caution! Special precautions should be taken in handling

thallium(I) compounds, which are toxic. Also, perchlorate salts

of organic cations may be explosive. Preparations on a larger scale

than that reported herein should be avoided.

General Procedures. Infrared spectra were recorded in the

range 4000-200 cm^-1on Perkin-Elmer 1430 and 16F-PC-FT

spectrometers, using Nujol mulls between polyethylene sheets.

Conductivities in acetone were measured with Philips PW9501

and Crison Micro CM2200 conductimeters. Melting points

were determined on a Reichert apparatus and are uncorrected.

C, H, N, and S analyses were carried out with a Carlo Erba

1106 microanalyzer. NMR spectra were recorded in Varian

Unity 300, Bruker AC-200, or Bruker Avance 300 or 400

Figure 18. X-ray packing of complex 25 showing the hydrogen

bond interactions along the b axis (only atoms involved in the

hydrogen bonding have been labeled). Details (including sym-

metry operators) are given in the Supporting Information.

atoms in an almost perfect square-planar geometry (angles

N-Pd-Br 87.92(14)°, N-Pd-Br(A) 92.08(14)°). The amine

ligands adopts a trans disposition, which is the normal

(73) Cattalini, L.; Martelli, M. J. Am. Chem. Soc. 1969, 91, 312.

4188 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

Chart 2. Numbering Schemes for Mono-, Di-, and Tri-inserted

Complexes

(s, CH, C5), 126.5 (s, CH, C3), 137.1 (s, CH, C6), 138.6 (s, C2),

141.5 (br s, C1, C-Pd).

Synthesis of [Pd{K²(C,N)-C₆H₄CH₂CH₂NHMe-2}Br(PPh₃)]

(2). PPh₃(125 mg, 0.476 mmol) was added to a solution of

complex 1 (150 mg, 0.243 mmol) in acetone (30 mL), and the

mixture was stirred for 3 h and then filtered through a plug

of MgSO₄. The filtrate was concentrated to ca. 5 mL. A pale

yellow solid precipitated, which was collected by filtration,

washed with acetone (2 ꢀ 1 mL), and air-dried to give complex

2. Yield: 160 mg, 0.279 mmol, 59%. Mp: 238 °C dec. Λ_M(Ω^-1

cm²mol^-1) = 0 (4.8 ꢀ 10^-4M). Anal. Calcd for C₂₇H₂₇BrNPPd

(582.798): C, 55.64; H, 4.67; N, 2.40. Found: C, 55.65; H, 4.37;

1

N, 2.48. IR (cm^-1): ν(NH) 3241. H NMR (400 MHz): δ 1.97

3

(m, 1 H, CH₂NH), 2.31 (dd, 3 H, Me, J_HH= 6.4, J_HP

4

=

2.8 Hz), 2.91 (m, 1 H, CH₂Ar), 3.38-3.46 (m, 2 H, 1 H of CH₂-

Ar + 1 H of CH₂NH), 4.49 (br s, 1 H, NH), 6.34 (br t, 1 H, H5,

³J_HH=7.6 Hz), 6.49 (ddd, 1 H, H6, ³J_HH=7.6, ⁴J_HP=4.8, ⁴J_HH

1.2 Hz), 6.77 (td, 1 H, H4, J_HH= 7.2, J_HH= 1.2 Hz), 6.87

=

3

4

3

4

(dd, 1 H, H3, J_HH= 7.4, J_HH=1.4 Hz), 7.25-7.30 (m,

6 H, m-H, PPh₃), 7.33-7.38 (m, 3 H, p-H, PPh₃), 7.51-7.57

(m, 6 H, o-H, PPh₃). ¹³C{¹H} NMR (100.81): δ 42.0 (d, Me,

³J_CP=2.5 Hz), 42.2 (s, CH₂Ar), 49.3 (d, CH₂NH, ³J_CP=2.3 Hz),

123.8 (s, CH, C4), 125.0 (d, CH, C5, ⁴J_CP=4.0 Hz), 125.7 (s, CH,

spectrometers, using CDCl₃solutions unless otherwise stated.

Chemical shifts are referenced to TMS (¹H and ¹³C{¹H}),

3

1

H₃PO₄(³¹P{¹H}), or CFCl₃(¹⁹F). Signals in the H and ¹³C

C3), 127.9 (d, m-CH, PPh₃, J_CP=10.5 Hz), 130.1 (d, p-CH,

4

1

PPh₃, J_CP=2.4 Hz), 131.5 (d, i-C, PPh₃, J_CP=49 Hz), 134.8

(d, o-CH, PPh₃, ³J_CP= 11.7 Hz), 135.6 (d, CH, C6, ³J_CP=10.8

Hz), 139.1 (s, C2), 155.0 (s, C1, C-Pd). ³¹P{¹H} NMR (121.50

MHz): δ 35.5 (s). Single crystals suitable for an X-ray diffrac-

tion study were obtained by slow diffusion of Et₂O into a

solution of 2 in CH₂Cl₂.

NMR spectra of most complexes were assigned with the help

of DEPT, APT, HMQC, and HMBC techniques. Nevertheless,

for di- and tri-inserted derivatives, most carbon resonances have

not been assigned, but signals corresponding to quaternary

carbons are indicated as C, and those corresponding to tertiary

carbons as CH.

Synthesis of [Pd{K²(C,N)-C₆H₄CH₂CH₂NHMe-2}(py)₂]ClO₄

(3). AgClO₄(80 mg, 0.37 mmol) was added to a solution of

complex 1 (120 mg, 0.187 mmol) in acetone (20 mL). The

resulting mixture was stirred for 30 min and then filtered

through a plug of MgSO₄to remove AgCl. Pyridine (0.05 mL,

0.50 mmol) was added to the filtrate, and the mixture was

stirred for 2 h and then filtered through a plug of MgSO₄. The

filtrate was concentrated to ca. 2 mL, and Et₂O (25 mL) was

added. The suspension was filtered, and the solid was washed

with Et₂O (2 ꢀ 3 mL) and air-dried to afford complex 3

as a yellow solid. Yield: 90 mg, 48%. Mp: 102 °C. Λ_M(Ω^-1

cm²mol^-1) = 148 (8.03 ꢀ 10^-4M). Anal. Calcd for C₁₉-

H₂₂ClN₃O₄Pd (498.255): C, 45.80; H, 4.45; N, 8.43. Found: C,

45.84; H, 4.40; N, 8.05. IR (cm^-1): ν(NH) 3230; ν(CdN) 1604. ¹H

NMR (400 MHz): δ 1.97 (m, 1 H, CH₂NH), 2.46 (d, 3 H, Me,

The ortho-metalated complexes [Pd₂{κ²(C,N)-C₆H₄CH₂-

NHCH₂Ph-2}₂(μ-Br)₂] (A),⁴²[Pd₂{κ²(C,N)-C₆H₃CH₂NH₂-

2,OMe-5}₂(μ-Br)₂] (B), [Pd₂{κ²(C,N)-C₆H₃CH₂NH₂-2,

Cl-5}₂(μ-Br)₂] (C), [Pd₂{κ²(C,N)-C₆H₃CH₂NH₂-2,F-5}₂(μ-

Br)₂] (D), [Pd₂{κ²(C,N)-C₆H₃CH₂NH₂-2,NO₂-5}₂(μ-Br)₂]

(E),³⁸[Pd₂{κ²(C,N)-C₆H₄CH₂CH₂NH₂-2}₂(μ-Br)₂] (F),³⁸and

[Pd₂{κ²(C,N)-C₆H₄CH₂CMe₂NH₂-2}₂(μ-Cl)₂] (G)⁷²were pre-

pared as previously reported.

N-Methylphenethylamine, silver perchlorate, 3-hexyne,

ethyl phenylpropiolate (Aldrich), methyl phenylpropiolate

(Lancaster), dimethyl acetylenedicarboxylate (Alfa Aesar), 2-

butyne, diphenylacetylene, triphenylphosphine, tert-butyl iso-

cyanide (Fluka), pyridine (Merck), and palladium acetate

(Johnson Matthey) were used as received. TlOTf (TlSO₃CF₃)

was prepared by reaction of Tl₂CO₃and HSO₃CF₃(1:2) in water

and recrystallized from acetone/Et₂O. Charts 1 and 2 give the

numbering schemes for the new palladacycles.

2

3

³J_HH= 6.0 Hz), 3.00 (dt, 1 H, CH₂Ar, J_HH= 14.4, J_HH

=

2.8 Hz), 3.26 (m, 1 H, CH₂NH), 3.39 (ddd, 1 H, CH₂Ar, ²J_HH

14.4, ³J_HH= 11.2, ³J_HH= 3.2 Hz), 4.72 (m, 1 H, NH), 6.52 (d, 1 H,

H6, C₆H₄, ³J_HH= 7.6 Hz), 6.69 (m, 1 H, H5, C₆H₄), 6.93-6.97 (m,

2 H, H4 and H5, C₆H₄), 7.32 (“t”, 2 H, m-H, py^a, ³J_HH= 6.8 Hz),

7.52 (“t”, 2 H, m-H, py^b, ³J_HH= 6.8 Hz), 7.79 (m, 2 H, p-H of py^a

and p-H of py^b), 8.57 (d, 2 H, o-H, py^a, ³J_HH= 4.8 Hz), 8.90 (br d,

Synthesis of [Pd₂{K²(C,N)-C₆H₄CH₂CH₂NHMe-2}₂(μ-Br)₂]

(1). N-Methylphenethylamine (0.520 mL, 3.60 mmol) and Pd

(OAc)₂(800 mg, 3.60 mmol) were refluxed in acetonitrile

(20 mL) for 5 h, and the resulting suspension was filtered

through a plug of Celite. The filtrate was concentrated to

dryness, and acetone (20 mL) and solid NaBr (2 g, 20 mmol)

were added to the residue. The suspension was stirred for 14 h

and concentrated to dryness, and CH₂Cl₂(30 mL) was added.

The mixture was filtered through a plug of MgSO₄, the filtrate

was concentrated to ca. 2 mL, and Et₂O (30 mL) was added.

The suspension was filtered, and the solid was air-dried and

recrystallized from CH₂Cl₂/Et₂O to afford complex 1 as an

orange solid. Yield: 751 mg, 65%. Mp: 162 °C. Λ_M(Ω^-1cm²

mol^-1) = 0 (6.2 ꢀ 10^-4M). Anal. Calcd for C₁₈H₂₄Br₂N₂Pd₂

(641.022): C, 33.73; H, 3.77; N, 4.37. Found: C, 33.52; H, 3.79;

2 H, o-H, py^b, J_HH=3.6 Hz). ¹³C{¹H} NMR (100.81 MHz): δ

3

39.8 (s, CH₂Ar), 42.6 (s, Me), 51.4 (s, CH₂NH), 124.5 (s, CH,

C5, C₆H₄), 124.9 (s, CH, C5, C₆H₄), 125.9 (s, m-CH, py^a), 126.2

(s, m-CH, py^b), 126.4 (s, CH, C3, C₆H₄), 134.4 (s, CH, C6,

C₆H₄), 138.6 (s, p-CH, py^a), 138.8 (s, p-CH, py^b), 140.7 (s,

C2, C₆H₄), 143.3 (s, C1, C₆H₄), 150.2 (s, o-CH, py^b), 152.0 (s, o-

CH, py^a).

Synthesis of [Pd₂{K²(C,N)-C(Ph)dC(CO₂Me)C₆H₄CH₂NH-

CH₂Ph-2}₂(μ-Br)₂] (4a). A solution of PhCtCCO₂Me (0.093 mL,

0.629 mmol) in acetone (10 mL) was added dropwise to a solution of

complex A (253 mg, 0.327 mmol) in acetone (20 mL). The resulting

mixture was stirred for 16 h and then filtered through a plug of

MgSO₄. The filtrate was concentrated to ca. 2 mL, and a 1:1 mixture

of Et₂O and n-hexane (25 mL) was added. The suspension was

filtered, and the solid was washed with a 1:1 mixture of Et₂O and n-

hexane (2 ꢀ 5 mL) and air-dried to give complex 4a as a yellow solid.

Yield: 242 mg, 0.223 mmol, 68%. Mp: 145-147 °C. Λ_M(Ω^-1cm²

mol^-1) = 0 (5.2 ꢀ 10^-4M). Anal. Calcd for C₄₈H₄₄Br₂N₂O₄Pd₂

1

N, 4.32. IR (cm^-1): ν(NH) 3230. H NMR (400 MHz): δ 1.97

(m, 1 H, CH₂NH), 2.67 (d, 3 H, Me, ³J_HH= 6.0 Hz), 2.98 (m, 2

H, 1 H of CH₂Ar + 1 H of CH₂NH), 3.20 (m, 1 H, CH₂Ar), 3.83

(br s, 1 H, NH), 6.81 (t, 1 H, H5, ³J_HH= 7.2 Hz), 6.85 (d, 1 H,

H3, ³J_HH= 7.2 Hz), 6.92 (t, 1 H, H4, ³J_HH= 7.2 Hz), 7.39 (br d,

3

1 H, H6, J_HH=6.0 Hz). ¹³C NMR (100.81 MHz): δ 40.3 (s,

CH₂Ar), 43.6 (s, Me), 50.1 (s, CH₂NH), 124.6 (s, CH, C4), 124.7

Article

Organometallics, Vol. 28, No. 14, 2009 4189

(1085.508): C, 53.11; H, 4.08; N, 2.58. Found: C, 53.00; H, 4.08; N,

2.69. IR (cm^-1): ν(NH) 3203; ν(CO) 1697 vs. The ¹H NMR

spectrum of complex 4a in CDCl₃(300 MHz) shows broad signals

that are overlapped and thus impossible to assign and integrate.

Nevertheless, the presence of two singlets in the region correspond-

ing to the OMe groups (3.35 and 3.37 ppm) indicates that compound

4a is a mixture of two isomers (see Results and Discussion section).

Synthesis of [Pd₂{K²(C,N)-C(Ph)dC(CO₂Et)C₆H₄CH₂NH-

CH₂Ph-2}₂(μ-Br)₂] (4b). A solution of PhCtCCO₂Et (0.138 mL,

0.836 mmol) in acetone (10 mL) was added dropwise to a solution of

complex A (343 mg, 0.448 mmol) in acetone (20 mL). The resulting

mixture was stirred for 20 h and then filtered through a plug

of MgSO₄. The filtrate was concentrated to ca. 2 mL, and n-hexane

(25 mL) was added. The suspension was filtered, and the solid was

washed with n-hexane (2 ꢀ 3 mL) and air-dried to give complex 4b as

a yellow solid. Yield: 350 mg, 0.314 mmol, 70%. Mp: 133-134 °C.

Λ_M(Ω^-1cm²mol^-1)=0 (3.6 ꢀ 10^-4M). Anal. Calcd for

C₅₀H₄₈Br₂N₂O₄Pd₂(1113.562): C, 53.93; H, 4.34; N, 2.52. Found:

C, 53.53; H, 4.04; N, 2.64. IR (cm^-1): ν(NH) 3212; ν(CO) 1687 vs.

The ¹H NMR spectrum of complex 4b in CDCl₃(300 MHz) shows

broad signals that are overlapped and thus impossible to assign

and integrate. Nevertheless, the presence of two triplets in the

region corresponding to the Me groups (0.79 and 0.80 ppm)

indicates that 4b is a mixture of two isomers (see Results and

Discussion section).

(m, 29 H, Ph and C₆H₄). ¹³C{¹H} NMR (100.81 MHz): δ 13.7 (s,

Me), 51.0 (s, CH₂Ar), 57.5 (s, CH₂Ph), 60.2 (s, CH₂O), 126.5, (s,

CH), 127.0 (s, CH), 127.1 (s, m-CH, Ph), 127.6 (d, o-CH, PhCdC,

⁴J_CP=1.9 Hz), 127.8 (d, m-CH, PPh₃, ³J_CP=10.8 Hz), 128.3 (s,

CH), 128.6 (d, C, J_CP=3.1 Hz), 128.7 (s, CH), 128.8 (s, CH), 128.9

(s, m-CH, Ph), 129.2 (s, o-CH, PhCH₂), 129.9 (s, CH, C7, C₆H₄),

130.1 (d, p-CH, PPh₃, ⁴J_CP=2.4 Hz), 131.1 (d, i-C, PPh₃, ¹J_CP

=

2

50.5 Hz), 134.6 (d, o-CH, PPh₃, J_CP=11.4 Hz), 135.9 (s, C,

C₆H₄), 136.6 (d, i-C, PhCH₂, ⁴J_CP=2.5 Hz), 142.0 (s, C, C₆H₄),

143.8 (d, C, J_CP=4.9 Hz), 166.7 (d, CO, ⁴J_CP= 2.0 Hz), 173.6 (d,

C, ⁴J_CP=1.9 Hz). ³¹P{¹H} NMR (162.29 MHz): δ 29.3 (s).

Synthesis of Pd{K²(C,N)-C(Ph)dC(CO₂Me)C₆H₄CH₂NH-

t

CH₂Ph-2}Br(CN^tBu)] (6a). BuNC (0.019 mL, 0.168 mmol)

was added to a solution of complex 4a (90 mg, 0.082 mmol) in

CH₂Cl₂(20 mL). The resulting mixture was stirred for 22 h and

then filtered through a plug of MgSO₄. The filtrate was con-

centrated to ca. 2 mL, and Et₂O (25 mL) was added. The

suspension was filtered, and the solid was washed with Et₂O

(2ꢀ5 mL) and air-dried to give complex 6a as a yellow solid.

Yield: 75 mg, 0.12 mmol, 73%. Mp: 195 °C. Λ_M(Ω^-1cm²

mol^-1) = 0 (6.40 ꢀ 10^-4M). Anal. Calcd for C₂₉H₃₁BrN₂O₂Pd

(625.888): C, 55.65; H, 4.99; N, 4.47. Found: C, 55.77; H, 5.27;

1

N, 4.65. IR (cm^-1): ν(NH) 3177; ν(CN) 2216; ν(CO) 1717. H

t

NMR (400 MHz): δ 1.34 (s, 9 H, Bu), 3.42 (s, 3 H, OMe),

=

3.50 (m, 1 H, CH₂Ar), 3.61 (“t”, 1 H, CH₂Ar, ²J_HH= ³J_HH

Synthesis of [Pd{K²(C,N)-C(Ph)dC(CO₂Me)C₆H₄CH₂NH-

CH₂Ph-2}Br(PPh₃)] (5a). PPh₃(22 mg, 0.08 mmol) was added

to a solution of complex 4a (45 mg, 0.04 mmol) in acetone

(20 mL). The resulting mixture was stirred for 24 h and then

filtered through a plug of MgSO₄. The filtrate was concentrated

to ca. 2 mL, and a 1:1 mixture of Et₂O and n-hexane (25 mL) was

added. The suspension was filtered, and the solid was washed

with a 1:1 mixture of Et₂O and n-hexane (2 ꢀ 5 mL) and air-

dried to afford complex 5a as a yellow solid. Yield: 45 mg,

0.06 mmol, 67%. Mp: 220 °C. Λ_M(Ω^-1cm²mol^-1)=0 (3.4 ꢀ

10^-4M). Anal. Calcd for C₄₂H₃₇BrNO₂PPd (805.046): C, 62.66;

H, 4.63; N, 1.74. Found: C, 62.75; H, 4.90; N, 1.82. IR (cm^-1):

ν(NH) 3233; ν(CO) 1710. ¹H NMR (400 MHz): δ 3.39 (s,

11.8 Hz), 3.81 (“t”, 1 H, CH₂Ph, ²J_HH=³J_HH= 11.8 Hz), 4.07

2

(m, 1 H, NH), 4.82 (d, 1 H, CH₂Ph, J_HH=12.4 Hz), 7.03 (d,

1 H, H3, C₆H₄, ³J_HH=7.6 Hz), 7.21-7.25 (m, 2 H, H4 of C₆H₄

and p-H of PhCdC), 7.32-7.31 (m, 4 H, o- and m-H, PhCdC),

7.38-7.47 (m, 6 H, H5 of C₆H₄and o-, m-, and p-H of PhCH₂),

7.62 (d, 1 H, H6, C₆H₄, ³J_HH= 7.6 Hz). ¹³C{¹H} NMR (100.81

MHz): δ 29.8 (s, CMe₃), 51.3 (s, CH₂Ar), 51.4 (s, OMe), 57.7 (s,

CH₂Ph), 58.1 (br s, CMe₃), 126.1 (s, o-CH or m-CH, PhCdC),

126.2 (s, p-CH, PhCdC), 127.3 (br s, CN), 127.5 (s, CH, C4,

C₆H₄), 128.0 (s, o-CH or m-CH, PhCdC), 128.6 (s, p-CH,

PhCH₂), 128.9 (s, CH, C5, C₆H₄), 129.0 (s, m-CH, PhCH₂),

129.4 (s, o-CH, PhCH₂), 129.6 (s, CH, C3 + C6, C₆H₄), 130.5 (s,

C^β), 134.0 (s, C2), 135.6 (s, i-C, PhCH₂), 140.0 (s, C1), 147.0 (s,

i-C, PhCdC), 166.3 (s, CO), 168.6 (s, C^R, C-Pd).

3 H, OMe), 3.52 (m, 1 H, CH₂Ar), 3.65 (“t”, 1 H, CH₂Ar, ²J_HH

=

Synthesis of [Pd{K²(C,N)-C(Ph)dC(CO₂Et)C₆H₄CH₂NH-

³J_HH=11.8 Hz), 3.76 (“t”, 1 H, CH₂Ph, ²J_HH= ³J_HH= 12.0 Hz),

4.68 (m, 1 H, NH), 4.87 (“d”, 1 H, CH₂Ph, ²J_HH=12.8 Hz), 7.04-

7.47 (m, 29 H, Ph and C₆H₄). ¹³C{¹H} NMR (100.81 MHz): δ 51.0

t

CH₂Ph-2}Br(CN^tBu)] (6b). BuNC (0.021 mL, 0.186 mmol)

was added to a solution of complex 4b (100 mg, 0.090 mmol)

in CH₂Cl₂(20 mL). The resulting mixture was stirred for 24 h

and then filtered through a plug of MgSO₄. The filtrate was

concentrated to ca. 2 mL, and Et₂O (25 mL) was added. The

suspension was filtered, and the solid was washed with Et₂O (2 ꢀ

5 mL) and air-dried to give complex 6b as a yellow solid. Yield:

60 mg, 0.09 mmol, 53%. Mp: 188 °C. Λ_M(Ω^-1cm²mol^-1) = 0

(6.25 ꢀ 10^-4M). Anal. Calcd for C₃₀H₃₃BrN₂O₂Pd (639.915):

C, 56.31; H, 5.20; N, 4.38. Found: C, 56.54; H, 5.36; N, 4.30. IR

(cm^-1): ν(NH) 3167; ν(CN) 2217; ν(CO) 1704. ¹H NMR

(d, CH₂Ar, ³J_CP= 2.1 Hz), 51.3 (s, OMe), 57.6 (d, CH₂Ph, ³J_CP

=

1.4 Hz), 126.6 (s, CH), 127.1 (s, CH), 127.2 (s, m-CH, Ph), 127.5 (d,

4

o-CH, PhCdC, J_CP= 2.2 Hz), 127.8 (d, m-CH, PPh₃, J_CP

3

=

10.8 Hz), 128.1 (d, C, J_CP=3.3 Hz), 128.3 (s, CH), 128.7 (s, CH),

128.8 (s, CH), 128.9 (s, m-CH, Ph), 129.2 (s, o-CH, PhCH₂), 129.9 (s,

CH, C3, C₆H₄), 130.1 (d, p-CH, PPh₃, ⁴J_CP= 2.3 Hz), 131.0 (d, i-C,

PPh₃,¹J_CP= 50.8 Hz), 134.5 (d, o-CH, PPh₃,²J_CP= 11.5 Hz), 135.8

(s, C, C₆H₄), 136.6 (d, i-C, PhCH₂,⁴J_CP=2.4 Hz), 141.8 (d, C, C₆H₄,

⁴J_CP=2.7 Hz), 143.7 (d, C, J_CP=5.3 Hz), 167.3 (d, CO,

⁴J_CP=2.0 Hz), 173.3 (d, C, J_CP=1.9 Hz). ³¹P{¹H} NMR (162.29

MHz): δ 29.5 (s). Single crystals suitable for an X-ray diffraction

study were obtained by slow diffusion of Et₂O into a solution of 5a in

CHCl₃.

3

(400 MHz): δ 0.85 (t, 3 H, Me, J_HH=7.2 Hz), 1.35 (s, 9 H,

2

3

^tBu), 3.42 (dd, 1 H, CH₂Ar, J_HH=11.4, J_HH= 4.4 Hz), 3.62

(“t”, 1 H, CH₂Ar, ²J_HH=³J_HH=11.4 Hz), 3.81 (dd, 1 H, CH₂Ph,

²J_HH=13.0, ³J_HH=11.4 Hz), 3.87 (m, 2 H, CH₂O), 4.07 (m, 1 H,

NH), 4.82 (dd, 1 H, CH₂Ph, ²J_HH= 13.0, ³J_HH= 1.8 Hz), 7.02

(dd, 1 H, H3, C₆H₄, ³J_HH=7.6, ⁴J_HH= 0.8 Hz), 7.20-7.24 (m, 2

H, H4 of C₆H₄and p-H of PhCdC), 7.30-7.31 (m, 4 H, o- and

m-H of PhCdC), 7.39-7.49 (m, 6 H, H5 of C₆H4 and o-, m-, and

p-H of PhCH₂), 7.63 (dd, 1 H, H6, C₆H₄, ³J_HH= 7.6, ⁴J_HH=0.8

Hz). ¹³C{¹H} NMR (100.81 MHz): δ 13.6 (s, Me), 29.8 (s,

CMe₃), 51.4 (s, CH₂Ar), 57.7 (s, CH₂Ph), 58.1 (br s, CMe₃),

60.3 (s, CH₂O), 126.0 (s, p-CH, PhCdC), 126.2 (s, o-CH or m-

CH, PhCdC), 127.4 (s, CH, C4, C₆H₄), 127.9 (s, o-CH or m-CH,

PhCdC), 128.6 (s, p-CH, PhCH₂), 128.9 (s, CH, C5, C₆H₄),

129.0 (s, m-CH, PhCH₂), 129.4 (s, o-CH, PhCH₂), 129.5 (s, CH,

C3 or C6, C₆H₄), 129.6 (s, CH, C3 or C6, C₆H₄), 131.0 (s, C^β),

134.0 (s, C2), 135.7 (s, i-C, PhCH₂), 140.1 (s, C1), 147.2 (s,

i-C, PhCdC), 166.0 (s, CO), 168.0 (s, C^R, C-Pd). The ¹³C NMR

resonance corresponding to the CN group was not observed.

Synthesis of [Pd{K²(C,N)-C(Ph)dC(CO₂Et)C₆H₄CH₂NH-

CH₂Ph-2}Br(PPh₃)] (5b). PPh₃(35 mg, 0.133 mmol) was added

to a solution of complex 4b (74 mg, 0.072 mmol) in acetone

(20 mL). Within 1 h, a yellow precipitate appeared. The resulting

suspension was further stirred for 7 h, and the solid was collected

by filtration, washed with Et₂O (2 ꢀ 5 mL), and air-dried to give

complex 5b as a yellow solid. The insolubility of 5b in acetone

prevented us from measuring its conductivitiy. Yield: 60 mg, 0.073

mmol, 51%. Mp: 240 °C. Anal. Calcd for C₄₃H₃₉BrNO₂PPd

(819.073): C, 63.06; H, 4.80; N, 1.71. Found: C, 62.89; H, 4.80; N,

1.73. IR (cm^-1): ν(NH) 3232; ν(CO) 1707. ¹H NMR (400 MHz):

3

δ 0.92 (t, 3 H, Me, J_HH=7.2 Hz), 3.52 (m, 1 H, CH₂Ar), 3.66

(“t”, 1 H, CH₂Ar, ²J_HH=³J_HH=11.8 Hz), 3.74 (“t”, 1 H, CH₂Ph,

²J_HH=³J_HH=12.4 Hz), 3.88 (m, 2 H, CH₂O), 4.66 (m,

2

1 H, NH), 4.84 (d, 1 H, CH₂Ph, J_HH= 12.4 Hz), 7.03-7.46

4190 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

Single crystals suitable for an X-ray diffraction study were

obtained by slow diffusion of n-hexane into a solution of 6b in

CH₂Cl₂.

48.09; H, 5.87; N, 2.99. IR (cm^-1): ν(NH) 3128, 3210, 3300.

¹H NMR (300 MHz): δ 0.99 (t, 3 H, Me, ³J_HH= 7.5 Hz), 1.11 (t,

3 H, Me, ³J_HH= 7.5 Hz), 1.14 (t, 3 H, Me, ³J_HH= 7.5 Hz), 1.31

3

2

Synthesis of [Pd{K²(C,N)-C(Et)dC(Et)C(Et)dC(Et)C₆H₃-

CH₂NH₂-2,Cl-5}Br] (7a). EtCtCEt (0.210 mL, 1.85 mmol)

was added to a suspension of complex C (150 mg, 0.230 mmol)

in acetone (20 mL). The resulting mixture was refluxed for 6 h

and then filtered through a plug of MgSO₄. The filtrate was

concentrated to ca. 2 mL, and a 1:1 mixture of n-hexane and n-

pentane (25 mL) was added. The suspension was filtered, and

the solid was washed with a 1:1 mixture of n-hexane and n-

pentane (2 ꢀ 5 mL) and air-dried to give complex 7a as a yellow

solid. Yield: 121 mg, 0.246 mmol, 53%. Mp: 145-148 °C. Λ_M

(Ω^-1cm²mol^-1) = 0 (6.10 ꢀ 10^-4M). Anal. Calcd for

C₁₉H₂₇BrClNPd (491.194): C, 46.46; H, 5.54; N, 2.85. Found:

C, 46.68; H, 5.52; N, 2.88. IR (cm^-1): ν(NH) 3128, 3203, 3295.

¹H NMR (300 MHz): δ 1.00 (t, 3 H, Me, ³J_HH=7.5 Hz), 1.12 (t, 3

H, Me, ³J_HH=7.5 Hz), 1.15 (t, 3 H, Me, ³J_HH=7.5 Hz), 1.31 (t, 3

(t, 3 H, Me, J_HH=7.5 Hz), 1.52 (“t”, 1 H, NH₂, J_HH=

³J_HH= 12.0 Hz), 1.72 (m, 1 H, CH₂Me), 1.91 (m, 1 H, CH₂Me),

2.10 (m, 1 H, CH₂Me), 2.20-2.49 (m, 4 H, CH₂Me), 2.62 (m,

1 H, CH₂Me), 2.72 (m, 1 H, NH₂), 3.80 (dt, 1 H, CH₂, ²J_HH

=

3

2

12.9, J_HH=2.4 Hz), 4.17 (“t”, 1 H, CH₂, J_HH= ³J_HH

13.0 Hz), 6.86 (dd, 1 H, H6, ³J_HF=9.3, ⁴J_HH= 2.7 Hz), 6.96 (td,

1 H, H4, ³J_HH=³J_HF=8.1, ⁴J_HH=2.7 Hz), 7.21 (dd, 1 H, H3,

4

³J_HH= 8.4, J_HF= 5.7 Hz). ¹³C{¹H} NMR (75.40 MHz):

δ 12.3 (s, Me), 14.6 (s, Me), 14.7 (s, Me), 22.3 (s, CH₂), 26.1 (s,

CH₂), 26.8 (s, CH₂), 33.9 (s, CH₂), 46.3 (s, CH₂N), 95.9 (s, C),

2

114.3 (s, C), 114.4 (d, CH, J_CF₃=20.6 Hz), 117.8 (d, CH,

²J_CF= 21.2 Hz), 131.6 (d, CH, J_CF=8.6 Hz), 132.4 (d, C,

⁴J_CF=2.9 Hz), 133.4 (s, C), 141.8 (d, C, ³J_CF=6.9 Hz), 142.3 (s,

C), 162.1 (d, C, ¹J_CF= 248.4 Hz).

Synthesis of [Pd{K²(C,N)-C(Ph)dC(Ph)C(Ph)dC(Ph)C₆H₃-

CH₂NH₂-2,F-5}Br] (8b). PhCtCPh (510 mg, 2.80 mmol) was

added to a suspension of complex D (177 mg, 0.285 mmol) in

CH₃CN (25 mL). The resulting mixture was refluxed for 7 h and

then filtered through a plug of MgSO₄. The filtrate was con-

centrated to ca. 2 mL, and Et₂O (25 mL) was added. The

suspension was filtered, and the solid was washed with Et₂O

(2 ꢀ5 mL) and air-dried to give complex 8b as a yellow

solid. Yield: 216 mg, 0.324 mmol, 57%. Mp: 218-219 °C. Λ_M

(Ω^-1cm²mol^-1) = 0 (4.80 ꢀ 10^-4M). Anal. Calcd for

C₃₅H₂₇BrFNPd (666.915): C, 63.03; H, 4.08; N, 2.10. Found:

3

H, Me, J_HH=7.5 Hz), 1.52 (m, 1 H, NH₂), 1.70 (m, 1 H,

CH₂Me), 1.92 (m, 1 H, CH₂Me), 2.10 (m, 1 H, CH₂Me), 2.20-

2.49 (m, 4 H, CH₂Me), 2.62 (m, 1 H, CH₂Me), 2.72 (m, 1 H,

NH₂), 3.79 (dt, 1 H, CH₂, J_HH=12.9, J_HH= 3.0 Hz), 4.17

2

3

2

(“t”, 1 H, CH₂, J_HH=³J_HH=12.6 Hz), 7.11 (d, 1 H, H6,

⁴J_HH= 2.4 Hz), 7.17 (d, 1 H, H3, ³J_HH= 8.4 Hz), 7.24 (dd, 1

H, H4, ³J_HH=8.1, ⁴J_HH= 2.4 Hz). ¹³C{¹H} NMR (50.30 MHz):

δ 12.4 (s, Me), 14.6 (s, Me), 14.8 (s, Me), 22.3 (s, CH₂), 26.1

(s, CH₂), 26.8 (s, CH₂), 34.2 (s, CH₂), 46.5 (s, CH₂N), 96.1 (s, C),

114.1 (s, C), 127.6 (s, CH), 130.7 (s, CH), 131.3 (s, CH), 133.5

(s, C), 134.0 (s, C), 135.0 (s, C), 141.5 (s, C), 142.5 (s, C).

Single crystals suitable for an X-ray diffraction study were

obtained by slow diffusion of n-hexane into a solution of 7a in

CH₂Cl₂.

C, 63.19; H, 4.07; N, 2.16. IR (cm^-1): ν(NH) 3128, 3203, 3295.

2

¹H NMR (300 MHz): δ 2.14 (“t”, 1 H, NH₂, J_HH=³J_HH

=

11.4 Hz), 2.72 (“t”, 1 H, CH₂, J_HH= ³J_HH=13.5 Hz), 3.13

2

(br d, 1 H, NH₂, ²J_HH=11.1 Hz), 3.56 (“d”, 1 H, CH₂, ²J_HH

=

13.8 Hz), 6.68-7.65 (m, 23 H, C₆H₃and Ph). ¹³C{¹H} NMR

(75.40 MHz): δ 46.6 (s, CH₂N), 90.1 (s, C), 111.2 (s, C), 115.1 (d,

CH, ²J_CF= 20.6 Hz), 120.2 (d, CH, ²J_CF= 22.6 Hz), 126.1 (s,

CH), 126.4 (s, CH), 126.5 (s, CH), 126.6 (s, CH), 127.1 (s, CH),

Synthesis of [Pd{K²(C,N)-C(Ph)dC(Ph)C(Ph)dC(Ph)C₆H₃-

CH₂NH₂-2,Cl-5}Br] (7b). PhCtCPh (550 mg, 3.00 mmol) was

added to a suspension of complex C (200 mg, 0.306 mmol) in

CH₃CN (25 mL). The resulting mixture was refluxed for 10 h

and then filtered through a plug of MgSO₄. The filtrate was

concentrated to ca. 2 mL, and Et₂O (25 mL) was added. The

suspension was filtered, and the solid was washed with Et₂O (2 ꢀ

5 mL) and air-dried to give complex 7b as a yellow solid. Yield:

195 mg, 0.285 mmol, 47%. Mp: 205 °C. Λ_M(Ω^-1cm²mol^-1) =

0 (5.85 ꢀ 10^-4M). Anal. Calcd for C₃₅H₂₇BrClNPd (683.37): C,

61.52; H, 3.98; N, 2.05. Found: C, 61.69; H, 3.44; N, 2.07. IR

(cm^-1): ν(NH) 3235, 3285. ¹H NMR (300 MHz): δ 2.16 (m, 1 H,

NH₂), 2.73 (“t”, 1 H, CH₂, ²J_HH= ³J_HH= 13.8 Hz), 3.13 (br d,

1 H, NH₂, ²J_HH=9.9 Hz), 3.55 (“d”, 1 H, CH₂, ²J_HH=13.2 Hz),

6.69-6.72 (m, 2 H, Ph), 6.87 (d, 1 H, H3, ³J_HH= 8.1 Hz), 6.91-

6.95 (m, 2 H, Ph), 7.00-7.02 (m, 3 H, Ph), 7.09-7.27 (m, 9 H of

Ph + H4), 7.34 (d, 1 H, H6, ⁴J_HH= 2.1 Hz), 7.59-7.64 (m, 4 H,

Ph). ¹³C{¹H} NMR (DMSO-d₆, 75.45 MHz): δ 45.7 (s, CH₂),

89.7 (s, C), 111.1 (s, C), 125.2 (s, CH), 126.1 (s, CH), 126.2 (s,

CH), 126.6 (s, CH), 126.9 (s, CH), 127.3 (s, CH), 127.6 (s, CH),

127.8 (s, CH), 127.9 (s, CH), 128.0 (s, CH), 128.3 (s, CH), 129.0

(s, CH), 130.7 (s, CH), 131.6 (s, CH), 132.0 (s, C), 132.2 (s, CH),

135.6 (s, C), 136.2 (s, C), 136.9 (s, C), 137.8 (s, C), 140.4 (s, C),

142.1 (s, C), 144.9 (s, C), 149.9 (s, C). Single crystals of

127.8 (s, CH), 127.9 (s, CH), 128.3 (s, CH), 128.4 (s, CH), 128.8

(s, CH), 129.3 (s, CH), 131.0 (s, CH), 131.9 (d, CH, J_CF=

3

4

8.1 Hz), 132.0 (d, C, J_CF=2.4 Hz), 135.9 (s, C), 136.6 (s, C),

137.9 (s, C), 141.1 (d, C, ³J_CF=7.1 Hz), 141.6 (s, C), 144.7 (s, C),

149.1 (s, C), 162.4 (d, C, ¹J_CF= 248.3 Hz).

Synthesis of [Pd{K²(C,N)-C(Et)dC(Et)C(Et)dC(Et)C₆H₃-

CH₂NH₂-2,NO₂-5}Br] (9). Complex E (180 mg, 0.267 mmol),

EtCtCEt (0.160 mL, 1.40 mmol), and CH₃CN (20 mL) were

mixed in a Carius tube and heated at 100 °C for 6 h. After

cooling, the resulting mixture was filtered through a plug of

MgSO₄. The filtrate was concentrated to ca. 2 mL, and Et₂O

(25 mL) was added. The suspension was filtered, and the solid

was washed with Et₂O (2 ꢀ 5 mL) and air-dried. Recrystalliza-

tion from CH₂Cl₂/Et₂O gave complex 9 as a dark orange solid.

Yield: 40 mg, 0.08 mmol, 15%. Mp: 216 °C dec. Λ_M(Ω^-1cm²

mol^-1)=0 (4.80 ꢀ 10^-4M). Anal. Calcd for C₁₉H₂₇BrN₂O₂Pd

(501.746): C, 45.48; H, 5.42; N, 5.58. Found: C, 45.45; H, 5.60;

1

N, 5.44. IR (cm^-1): ν(NH) 3132, 3209, 3300. H NMR (300

3

MHz): δ 1.04 (t, 3 H, Me, J_HH=7.5 Hz), 1.11 (t, 3 H, Me,

³J_HH=7.5 Hz), 1.16 (t, 3 H, Me, ³J_HH=7.5 Hz), 1.32 (t, 3 H, Me,

³J_HH= 7.5 Hz), 1.66 (m, 1 H, NH₂), 1.96 (m, 1 H, CH₂Me), 2.14

(m, 1 H, CH₂Me), 2.29 (m, 1 H, CH₂Me), 2.36-2.46 (m,

4 H, CH₂Me), 2.64 (m, 1 H, CH₂Me), 2.84 (m, 1 H, NH₂),

3.96 (dt, 1 H, CH₂, ²J_HH=13.5, ³J_HH= 2.4 Hz), 4.29 (td, 1 H,

7b 3DMSO suitable for an X-ray diffraction study were ob-

3

tained from a solution of 7b in DMSO.

Synthesis of [Pd{K²(C,N)-C(Et)dC(Et)C(Et)dC(Et)C₆H₃-

CH₂NH₂-2,F-5}Br] (8a). EtCtCEt (0.550 mL, 4.80 mmol)

was added to a suspension of complex D (300 mg, 0.483 mmol)

in acetone (20 mL). The resulting mixture was refluxed for 6 h

and then filtered through a plug of MgSO₄. The filtrate was

concentrated to ca. 2 mL, and a 1:1 mixture of n-hexane and

n-pentane (25 mL) was added. The suspension was filtered, and

the solid was washed with a 1:1 mixture of n-hexane and

n-pentane (2 ꢀ 5 mL) and air-dried to give complex 8a as a

yellow solid. Yield: 221 mg, 0.465 mmol, 48%. Mp: 141-142 °C.

Λ_M(Ω^-1cm²mol^-1) = 0 (6.70 ꢀ 10^-4M). Anal. Calcd for

C₁₉H₂₇BrFNPd (474.739): C, 48.07; H, 5.73; N, 2.95. Found: C,

CH₂, ²J_HH=³J_HH=13.5, ³J_HH=1.8 Hz), 7.45 (d, 1 H, H3, ³J_HH

=

8.4 Hz), 8.00 (d, 1 H, H6, J_HH= 2.4 Hz), 8.12 (dd, 1 H, H4,

4

³J_HH= 8.4, J_HH=2.4 Hz). ¹³C{¹H} NMR (75.40 MHz):

δ 12.5 (s, Me), 14.5 (s, Me), 14.7 (s, Me), 14.8 (s, Me), 22.5

(s, CH₂), 26.3 (s, CH₂), 27.0 (s, CH₂), 34.1 (s, CH₂), 46.7

(s, CH₂N), 96.6 (s, C), 112.6 (s, C), 122.3 (s, CH), 125.9 (s, CH),

131.3 (s, CH), 133.6 (s, C), 141.6 (s, C), 143.0 (s, C), 143.5 (s, C),

147.8 (s, C). Single crystals suitable for an X-ray diffraction

study were obtained by slow diffusion of Et₂O into a solution of 9

in CHCl₃.

Article

Synthesis of [Pd{K²(C,N)-C(Ph)dC(CO₂Me)C(Ph)dC(CO₂-

Organometallics, Vol. 28, No. 14, 2009 4191

Synthesis of [Pd₂{K²(C,N)-C(O)C(Et)dC(Et)C(Et)dC(Et)-

C₆H₃CH₂NH₂-2,Cl-5}₂(μ-Br)₂] (13a). CO was bubbled through

a solution of complex 7a (110 mg, 0.224 mmol) in CH₂Cl₂

(20 mL) for 1 h, and the resulting mixture was further stirred

for 24 h and then filtered through a plug of MgSO₄. The filtrate

was concentrated to ca. 2 mL, and Et₂O (25 mL) was added. The

suspension was filtered, and the solid was washed with Et₂O

(2 ꢀ 5 mL) and air-dried to give complex 13a as a yellow

solid. Yield: 45 mg, 0.043 mmol, 39%. Mp: 169-171 °C.

Me)C₆H₄CH₂NH-CH₂Ph-2}Br] and [Pd{K²(C,N)-C(CO₂Me)d

C(Ph)C(Ph)dC(CO₂Me)C₆H₄CH₂NH-CH₂Ph-2}Br] (10a,b).

PhCtCCO₂Me (0.165 mL, 1.111 mmol) was added to a

solution of complex A (122 mg, 0.157 mmol) in acetone (20 mL).

The resulting mixture was stirred for 10 h and then filtered through a

plug of MgSO₄. The filtrate was concentrated to ca. 2 mL, and n-

hexane (25 mL) was added. The suspension was filtered, and the

solid was washed with n-hexane (2 ꢀ 3 mL) and air-dried to give a

yellow solid, which was a mixture of both isomers 10a,b. Attempts to

separate this mixture were unsuccessful. Yield: 160 mg, 0.228 mmol,

73%. Λ_M(Ω^-1cm²mol^-1)=0 (5.70 ꢀ 10^-4M). Anal. Calcd for

C₃₄H₃₀BrNO₄Pd (702.926): C, 58.10; H, 4.30; N, 1.99. Found: C,

58.06; H, 4.40; N, 2.05. ¹H NMR (300 MHz): δ 2.62 (“d”, 2 H, CH₂,

²J_HH=14.1 Hz), 3.14-3.49 (m, 9 H, CH₂, NH and OMe), 3.85 (s,

3 H, OMe), 3.87 (s, 3 H, OMe), 3.89 (s, 3 H, OMe), 4.22-4.35 (m,

2 H, CH₂), 6.80-7.85 (m, 38 H, C₆H₄and Ph). The signals

corresponding to both isomers are overlapped and thus impossible

to assign and integrate. Nevertheless, a ca. 1:1 ratio of both isomers

can be estimated from the intensities corresponding to the OMe

groups.

Λ

_M(Ω^-1cm²mol^-1)=1 (3.08 ꢀ 10^-4M). Anal. Calcd for C₄₀-

H₅₄Br₂Cl₂N₂O₂Pd₂(1038.408): C, 46.27; H, 5.24; N, 2.70.

Found: C, 46.22; H, 5.16; N, 2.75. IR (cm^-1): ν(NH) 3230,

=

3305; ν(CO) 1675. ¹H NMR (300 MHz): δ1.04 (t, 3 H, Me, ³J_HH

3

7.5 Hz), 1.13 (t, 3 H, Me, J_HH= 7.5 Hz), 1.23 (t, 3 H, Me,

³J_HH= 7.5 Hz), 1.40 (t, 3 H, Me, ³J_HH=7.5 Hz), 1.47-1.59 (m, 2

H, 1 H of CH₂Me + 1 H of NH₂), 1.82 (m, 1 H, CH₂Me), 2.00-

2.27 (m, 4 H, CH₂Me), 2.46 (m, 1 H, CH₂Me), 2.69 (m, 1 H,

CH₂Me), 3.80 (d, 1 H, CH₂, ²J_HH=13.2 Hz), 3.94 (br d, 1 H, NH₂,

²J_HH= 9.6 Hz), 4.54 (“t”, 1 H, CH₂, ²J_HH= ³J_HH=13.5 Hz), 7.10

(d, 1 H, H6, ⁴J_HH=1.8 Hz), 7.16 (d, 1 H, H3, ³J_HH=8.4 Hz), 7.23

(dd, 1 H, H4, ³J_HH=8.1, ⁴J_HH=2.0 Hz). ¹³C{¹H} NMR (50.30

MHz): δ 12.7 (s, Me), 13.1 (s, Me), 13.8 (s, Me), 20.0 (s, CH₂), 23.1

(s, CH₂), 30.2 (s, CH₂), 33.8 (s, CH₂), 46.0 (s, CH₂N), 106.3 (s, C),

127.2 (s, C), 127.5 (s, CH), 129.2 (s, CH), 131.4 (s, CH), 134.1 (s, C),

136.2 (s, C), 142.3 (s, C), 148.0 (s, C), 162.9 (s, C), 213.0 (s, CO).

Synthesis of [Pd₂{K²(C,N)-C(O)C(Ph)dC(Ph)C(Ph)dC(Ph)-

C₆H₃CH₂NH₂-2,Cl-5}₂(μ-Br)₂] (13b). CO was bubbled through

a solution of complex 7b (110 mg, 0.161 mmol) in CH₂Cl₂

(20 mL) for 2 h, and the resulting mixture was further stirred

for 24 h and then filtered through a plug of MgSO₄. Formation

of metallic palladium was observed. The filtrate was concen-

trated to ca. 2 mL, and Et₂O (25 mL) was added. The suspension

was filtered, and the solid was washed with Et₂O (2ꢀ5 mL) and

air-dried to give complex 13b as a yellow solid. Complex 13b is

not soluble in acetone and barely soluble in other common

organic solvents such as CHCl₃or DMSO. Moreover, it decom-

poses slowly in solution. These features prevented us from

measuring its conductivitiy or recording its ¹³C NMR spectrum.

Yield: 83 mg, 0.058 mmol, 72%. Mp: 230-232 °C. Anal. Calcd

for C₇₂H₅₄Br₂Cl₂N₂O₂Pd₂(1422.76): C, 60.78; H, 3.82; N, 1.97.

Found: C, 60.69; H, 3.62; N, 1.93. IR (cm^-1): ν(NH) 3240,

3314; ν(CO) 1688. ¹H NMR (DMSO-d₆, 200 MHz): δ 1.71 (“t”,

Synthesis of [Pd{K²(C,N)-C(Ph)dC(CO₂Et)C(Ph)dC(CO₂-

Et)C₆H₄CH₂NH-CH₂Ph-2}Br] and [Pd{K²(C,N)-C(CO₂Et)d

C(Ph)C(Ph)dC(CO₂Et)C₆H₄CH₂NHCH₂Ph-2}Br] (11a,b). Ph-

CtCCO₂Et (0.155 mL, 0.939 mmol) was added to a solution of

complex A (120 mg, 0.157 mmol) in CH₂Cl₂(20 mL). The resulting

mixture was stirred for 24 h and then filtered through a plug of

MgSO₄. The filtrate was concentrated to ca. 2 mL, and n-hexane

(25 mL) was added. The suspension was filtered, and the solid was

washed with n-hexane (2 ꢀ 3 mL) and air-dried to give a yellow solid,

which was a mixture of both isomers 11a,b. Attempts to separate

this mixture were unsuccessful. Yield: 165 mg, 0.226 mmol, 72%.

Λ_M(Ω^-1cm²mol^-1) = 0 (5.50ꢀ 10^-4M). Anal. Calcd for

C₃₆H₃₄BrNO₄Pd (730.98): C, 59.15; H, 4.69; N, 1.92. Found: C,

58.85; H, 4.65; N, 1.89. ¹H NMR (200 MHz): δ 0.86 (t, 3 H, Me,

³J_HH=7.2 Hz), 1.21 (t, 3 H, Me, ³J_HH=7.0 Hz), 1.28 (t, 3 H, Me,

3

³J_HH=7.2 Hz), 1.36 (t, 3 H, Me, J_HH=7.1 Hz), 2.60-2.70 (m,

2 H, CH₂), 3.13-3.52 (m, 7 H, CH₂and NH), 3.89 (m, 2 H, CH₂),

4.14-4.56 (m, 7 H, CH₂and NH), 6.78-7.88 (m, 38 H, C₆H₄and

Ph). Most signals corresponding to both isomers are overlapped and

thus impossible to assign and integrate. Nevertheless, a ca. 1:1

relative ratio of both isomers can be estimated by the intensities

corresponding to the Me groups.

1 H, CH₂, ²J_HH=³J_HH=13.6 Hz), 2.92 (br d, 1 H, NH₂, ²J_HH

=

10.4 Hz), 3.42 (“d”, 1 H, CH₂, ³J_HH=14.0 Hz), 3.90 (“t”, 1 H,

Synthesis of [Pd{K²(C,N)-C(Ph)dC(CO₂Et)C(Ph)dC(CO₂-

Et)C₆H₃CH₂NH₂-2,F-5}Br] and [Pd{K²(C,N)-C(CO₂Et)d

C(Ph)C(Ph)dC(CO₂Et)C₆H₃CH₂NH₂-2,F-5}Br] (12a,b). Ph-

CtCCO₂Et (0.208 mL, 1.260 mmol) was added to a suspension

of complex D (130 mg, 0.209 mmol) in CH₂Cl₂(20 mL). The

resulting mixture was stirred for 24 h and then filtered through a

plug of MgSO₄. The filtrate was concentrated to ca. 2 mL, and n-

hexane (25 mL) was added. The suspension was filtered, and

the solid was washed with n-hexane (2 ꢀ 3 mL) and air-dried

to give a yellow solid, which was a mixture of both isomers

12a,b. Attempts to separate this mixture were unsuccessful.

Yield: 163 mg, 0.247 mmol, 60%. Λ_M(Ω^-1cm²mol^-1) = 0

(6.07 ꢀ 10^-4M). Anal. Calcd for C₂₉H₂₇BrFNO₄Pd (658.845):

NH₂, J_HH= ³J_HH= 10.8 Hz), 6.57-7.90 (m, 23 H, C₆H₃

2

and Ph).

Synthesis of [Pd₂{K²(C,N)-C(O)C(Et)dC(Et)C(Et)dC(Et)-

C₆H₃CH₂NH₂-2,F-5}₂(μ-Br)₂] (14a). CO was bubbled through

a solution of complex 8a (122 mg, 0.257 mmol) in CH₂Cl₂

(30 mL) for 2 h, and the resulting mixture was further stirred

for 24 h and then filtered through a plug of MgSO₄. The filtrate

was concentrated to ca. 2 mL, and Et₂O (25 mL) was added. The

suspension was filtered, and the solid was washed with Et₂O

(2ꢀ5 mL) and air-dried to give complex 14a 1/4CH₂Cl₂as a

3

yellow solid. Yield: 57 mg, 0.055 mmol, 43%. Mp: 175 °C. Λ_M

(Ω^-1cm²mol^-1) = 0 (2.73 ꢀ 10^-4M). Anal. Calcd for C₄₀-

C, 52.87; H, 4.13; N, 2.13. Found: C, 52.83; H, 3.96; N, 2.31. ¹H

H₅₄Br₂F₂N₂O₂Pd₂1/4CH₂Cl₂(1026.7313): C, 47.08; H, 5.35;

3

N, 2.73. Found: C, 46.90; H, 5.47; N, 2.70. IR (cm^-1): ν(NH)

3212, 3305; ν(CO) 1674. ¹H NMR (300 MHz): δ 1.04 (t, 3 H, Me,

³J_HH= 7.5 Hz), 1.14 (t, 3 H, Me, ³J_HH=7.5 Hz), 1.24 (t, 3 H,

Me, ³J_HH=7.5 Hz), 1.40 (t, 3 H, Me, ³J_HH=7.5 Hz), 1.46-1.58

(m, 2 H, 1 H of CH₂Me+1 H of NH₂), 1.81 (m, 1 H, CH₂Me),

1.97-2.30 (m, 4 H, CH₂Me), 2.44 (m, 1 H, CH₂Me), 2.69 (m, 1

H, CH₂Me), 3.80 (d, 1 H, CH₂, ²J_HH=13.2 Hz), 4.06 (br d, 1 H,

NH₂, ²J_HH= 9.9 Hz), 4.55 (“t”, 1 H, CH₂, ²J_HH=³J_HH= 13.5

Hz), 5.34 (s, CH₂Cl₂), 6.86 (dd, 1 H, H6, ³J_HF= 9.9, ⁴J_HH=2.4

Hz), 6.95 (td, 1 H, H4, ³J_HF= ³J_HH= 8.1, ⁴J_HH= 2.4 Hz), 7.19

(dd, 1 H, H3, ³J_HH= 8.4, ⁴J_HF= 5.7 Hz). ¹³C{¹H} NMR (75.40

MHz): δ 12.7 (s, Me), 13.0 (s, Me), 13.1 (s, Me), 13.9 (s, Me), 20.0

(s, CH₂), 23.0 (s, CH₂), 30.1 (s, CH₂), 33.7 (s, CH₂), 45.8

3

NMR (200 MHz): δ 0.86 (t, 3 H, Me, major isomer, J_HH

7.1 Hz), 1.15 (t, 3 H, Me, minor isomer J_HH= 7.1 Hz), 1.24

=

3

(t, 3 H, Me, major isomer, J_HH= 7.1 Hz), 1.33 (t, 3 H, Me,

minor isomer, ³J_HH=7.1 Hz), 2.01 (“t”, 1 H, NH₂, major isomer,

²J_HH=12.2Hz), 2.35(“t”,1H, NH₂, minor isomer, ²J_HH=12.6 Hz),

2.55-2.74 (m, 1 H of CH₂of minor isomer+1 H of CH₂of major

isomer), 3.02-3.10 (m, 1 H of NH₂of minor isomer+1 H of NH₂of

major isomer), 3.57 (br d, 1 H of CH₂of minor isomer+1 H of CH₂

of major isomer, ²J_HH=13.4 Hz), 3.88 (m, 2 H, CH₂, major isomer),

4.14-4.37 (m, 4 H of CH₂of minor isomer + 2 H of CH₂of major

isomer), 6.95-7.70 (m, 13 H of C₆H₃andPhofminorisomer+13H

of C₆H₃and Ph of major isomer). ¹⁹F NMR (282 MHz): δ -112.2

(m), -111.6 (m) (relative intensities: 12a:12b = 1:3).

4192 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

(s, CH₂N), 106.2 (s, C), 114.2 (d, CH, ²J_CF=20.7 Hz), 116.0 (d,

CH, ²J_CF=21.1 Hz), 126.3 (s, C), 131.6 (d, CH, ³J_CF= 8.6 Hz),

133.6 (d, C, ⁴J_CF= 3.0 Hz), 142.6 (d, C, ³J_CF= 6.5 Hz), 147.9 (s,

(m, 1 H, NH₂), 3.71 (s, OMe), 3.73 (s, OMe), 3.85 (s, OMe), 3.91

(s, OMe), 3.97 (s, OMe), 4.01 (s, OMe), 4.15 (m, 1 H, CH₂), 4.31

(m, 1 H, NH₂), 7.09 (d, 1 H, H3, ³J_HH=8.4 Hz), 7.19 (dd, 1 H,

H4, ³J_HH=8.4, ⁴J_HH=1.8 Hz), 7.55 (d, 1 H, H6, ⁴J_HH=1.8 Hz).

One proton of CH₂is obscured by the OMe groups. ¹³C{¹H}

NMR (50.30 MHz): δ 47.0 (s, C), 47.5 (s, CH₂), 52.6 (s, OMe),

52.7 (s, OMe), 53.0 (s, OMe), 53.1 (s, OMe), 53.8 (s, OMe), 57.1

(s, OMe), 127.2 (s, CH), 128.1 (s, CH), 130.1 (s, CH), 133.6 (s,

C), 133.8 (s, C), 133.9 (s, C), 136.7 (s, C), 137.3 (s, C), 142.7 (s, C),

148.9 (s, C), 160.7 (s, CO), 162.1 (s, CO), 162.4 (s, CO), 164.2 (s,

CO), 171.9 (s, CO), 183.6 (s, CO).

1

C), 162.4 (d, C, J_CF=247.8 Hz), 163.0 (s, C), 213.8 (s, CO).

Single crystals of 14a 2DMSO suitable for an X-ray diffraction

study were obtained from a solution of 14a 1/4CH₂Cl₂in

3

DMSO.

Synthesis of [Pd₂{K²(C,N)-C(O)C(Ph)dC(Ph)C(Ph)dC(Ph)-

C₆H₃CH₂NH₂-2,F-5}₂(μ-Br)₂] (14b). CO was bubbled through

a solution of complex 8b (125 mg, 0.187 mmol) in CH₂Cl₂

(20 mL) for 2 h, and the resulting mixture was further stirred

for 24 h and then filtered through a plug of MgSO₄. The filtrate

was concentrated to ca. 2 mL, and Et₂O (25 mL) was added. The

suspension was filtered, and the solid was washed with Et₂O (2 ꢀ

5 mL) and air-dried to give complex 14b as a yellow solid.

Yield: 127 mg, 0.091 mmol, 97%. Mp: 179-182 °C.

Λ_M(Ω^-1cm²mol^-1) = 0 (2.40 ꢀ 10^-4M). Anal. Calcd for

C₇₂H₅₄Br₂F₂N₂O₂Pd₂(1389.85): C, 62.22; H, 3.92; N, 2.02.

Found: C, 61.95; H, 3.86; N, 2.02. IR (cm^-1): ν(NH) 3240,

3314; ν(CO) 1688. ¹H NMR (DMSO-d₆, 200 MHz): δ 1.73 (“t”,

Synthesis of [Pd{K³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C-

(CO₂Me)C₆H₃CH₂NH₂-2,F-5}Br] (17). MeO₂CCtCCO₂Me

(0.200 mL, 1.63 mmol) was added to a suspension of complex

D (100 mg, 0.161 mmol) in CH₂Cl₂(20 mL). The resulting

mixture was stirred for 18 h and then filtered through a plug

of MgSO₄. The filtrate was concentrated to ca. 2 mL, and Et₂O

(25 mL) was added. The suspension was filtered, and the solid

was washed with Et₂O (2 ꢀ 5 mL) and air-dried to give complex

17 as a yellow solid. Yield: 134 mg, 0.182 mmol, 56%. Mp:

175 °C dec. Λ_M(Ω^-1cm²mol^-1)=0 (5.92 ꢀ 10^-4M). Anal.

Calcd for C₂₅H₂₅BrFNO₁₂Pd (736.777): C, 40.76; H, 3.42; N,

1.90. Found: C, 40.44; H, 3.31; N, 2.08. IR (cm^-1): ν(NH) 3128,

3200, 3254; ν(CO) 1728 vs, 1687 s, 1636 s. ¹H NMR (300 MHz):

δ 2.68 (m, 1 H, NH₂), 3.70 (s, 3 H, OMe), 3.74 (s, 3 H, OMe), 3.84

(s, 3 H, OMe), 3.90 (s, 3 H, OMe), 3.97 (s, 3 H, OMe), 4.02 (s,

3 H, OMe), 4.30 (m, 1 H, NH₂), 6.94 (ddd, 1 H, H4, ³J_HF=10.8,

1 H, CH₂, ²J_HH=³J_HH=12.8 Hz), 2.92 (br d, 1 H, NH₂, ²J_HH

=

10.4 Hz), 3.51 (“d”, 1 H, CH₂, ²J_HH=13.7 Hz), 3.93 (“t”, 1 H,

2

NH₂, J_HH=³J_HH=10.6 Hz), 6.83-7.90 (m, 23 H, C₆H₃and

Ph). ¹³C{¹H} NMR (DMSO-d₆, 50.30 MHz): δ 44.8 (s, CH₂N),

104.2 (d, C, ⁴J_CF=1.4 Hz), 114.7 (d, CH, ²J_CF=20.5 Hz), 119.8

(d, CH, J_CF=22.9 Hz), 122.4 (s, C), 127.3 (s, CH), 127.6 (s,

2

CH), 127.7 (s, CH), 127.8 (s, CH), 127.9 (s, CH), 128.0 (s, CH),

128.3 (s, CH), 128.5 (s, CH), 129.9 (s, CH), 130.1 (s, CH), 130.3

(s, CH), 130.8, (s, CH), 132.2 (d, CH, ³J_CF=8.1 Hz), 133.3 (s, C),

4

3

³J_HH= 8.4, J_HH= 2.4 Hz), 7.14 (dd, 1 H, H3, J_HH= 8.7,

⁴J_HF= 6 Hz), 7.27 (dd, 1 H, H6, ³J_HF= 10.5, ⁴J_HH= 2.4 Hz).

The two protons of CH₂are obscured by the OMe groups. ¹³

C

4

134.2 (d, C, J_CF=2.9 Hz), 135.2 (s, C), 138.5 (s, C), 140.2 (s,

=

{¹H} NMR (50.30 MHz): δ 47.1 (s, C), 47.6 (s, CH₂), 52.6 (s,

OMe), 52.8 (s, OMe), 53.0 (s, OMe), 53.8 (s, OMe), 57.1 (s,

OMe), 114.0 (d, CH, ²J_CF=22.5 Hz), 115.2 (d, CH, ²J_CF= 21.0

Hz), 130.5 (d, CH, ³J_CF=8.3 Hz), 131.1 (d, C, ⁴J_CF= 3.2 Hz),

134.5 (d, C, ³J_CF= 7.5 Hz), 137.2 (s, C), 142.7 (s, C), 149.2 (s, C),

160.7 (s, CO), 161.7 (d, C, ¹J_CF= 250.0 Hz), 162.1 (s, CO), 172.0

(s, CO), 183.6 (s, CO).

C), 140.3 (d, C, ³J_CF=6.7 Hz), 142.7 (s, C), 160.5 (d, C, ¹J_CF

243.9 Hz), 161.6 (s, C), 212.9 (s, CO).

Synthesis of [Pd{K³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C-

(CO₂Me)C₆H₃CH₂NH₂-2,OMe-5}Br] (15). MeO₂CCtCCO₂-

Me (0.125 mL, 1.02 mmol) was added to a suspension of

complex B (90 mg, 0.14 mmol) in CH₂Cl₂(20 mL). The resulting

mixture was stirred for 48 h and then filtered through a plug

of MgSO₄. The filtrate was concentrated to ca. 2 mL, and Et₂O

(25 mL) was added. The suspension was filtered, and the solid

was washed with Et₂O (2 ꢀ 5 mL) and air-dried to give complex

15 as a yellow solid. Yield: 136 mg, 0.182 mmol, 65%. Mp:

168 °C. Λ_M(Ω^-1cm²mol^-1) = 0 (5.45 ꢀ 10^-4M). Anal. Calcd

for C₂₆H₂₈BrNO₁₃Pd (748.813): C, 41.70; H, 3.77; N, 1.87.

Found: C, 41.52; H, 3.67; N, 2.06. IR (cm^-1): ν(NH) 3184,

3286; ν(CO) 1728 vs, 1667 s, 1626 s. ¹H NMR (300 MHz): δ 2.68

(m, 1 H, NH₂), 3.63 (s, 3 H, C₆H₃OMe), 3.70 (s, 3 H, OMe), 3.73

(s, 3 H, OMe), 3.81 (s, 3 H, OMe), 3.90 (s, 3 H, OMe), 3.96 (s, 3

H, OMe), 4.02 (s, 3 H, OMe) 4.25 (m, 1 H, NH₂), 6.77 (dd, 1 H,

H4, ³J_HH=8.7, ⁴J_HH=2.4 Hz), 7.04 (d, 1 H, H3, ³J_HH=8.4 Hz),

7.10 (d, 1 H, H6, ⁴J_HH=2.4 Hz). The two protons of CH₂are

obscured by the OMe groups. ¹³C{¹H} NMR (50.30 MHz): δ

47.6 (s, CH₂), 48.1 (s, C), 52.6 (s, OMe), 52.7 (s, OMe), 52.9 (s,

OMe), 53.0 (s, OMe), 53.7 (s, OMe), 55.1 (s, C₆H₃OMe), 57.0 (s,

OMe), 110.5 (s, CH, C6), 116.1 (s, CH, C4), 127.3 (s, C), 130.0 (s,

CH, C3), 133.2 (s, C), 137.0 (s, C), 142.4 (s, C), 150.1 (s, C), 159.1

(s, C), 160.9 (s, CO), 162.1 (s, CO), 162.5 (s, CO), 164.4 (s, CO),

172.4 (s, CO), 183.5 (s, CO).

Synthesis of [Pd{K³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C-

(CO₂Me)C₆H₄CH₂NHCH₂Ph-2}Br] (18). MeO₂CCtCCO₂Me

(0.77 mL, 6.45 mmol) was added to a suspension of complex A

(300 mg, 0.392 mmol) in CH₂Cl₂(20 mL). The resulting mixture

was stirred for 70 h and then filtered through a plug of MgSO₄.

The filtrate was concentrated to ca. 2 mL, and Et₂O (25 mL) was

added. The suspension was filtered, and the solid was washed

with Et₂O (2ꢀ3 mL) and air-dried to give complex 18 as a yellow

solid. Yield: 570 mg, 0.705 mmol, 90%. Mp: 196-198 °C. Λ_M

(Ω^-1cm²mol^-1) = 0 (5.20 ꢀ 10^-4M). Anal. Calcd for C₃₂-

H₃₂BrNO₁₂Pd (808.912): C, 47.51; H, 3.99; N, 1.73. Found: C,

47.49; H, 4.11; N, 1.81. IR (cm^-1): ν(NH) 3232; ν(CO) 1750 s,

1728 vs, 1683 s, 1636 s. ¹H NMR (400 MHz): δ 3.29 (br d, 1 H,

2

CH₂Ar, J_HH=14.0 Hz), 3.54 (dd, 1 H, CH₂Ph, J_HH=13.2,

³J_HH=11.2 Hz), 3.67 (s, 3 H, OMe), 3.73 (s, 3 H, OMe), 3.81 (s, 3

H, OMe), 3.94 (s, 3 H, OMe), 3.96 (m, 1 H, CH₂Ph, partially

obscured by OMe), 3.99 (s, 3 H, OMe), 4.04 (s, 3 H, OMe), 4.34

2

3

(dd, 1 H, CH₂, J_HH=14.8, J_HH=2.4 Hz), 5.02 (br d, 1 H,

3

NH, J_HH=10.0 Hz), 7.01 (br d, 1 H, H3, C₆H₄, J_HH

6.4 Hz), 7.10-7.12 (m, 2 H, Ph), 7.21-7.28 (m, 2 H, H4+H5,

C₆H₄), 7.33-7.34 (m, 3 H, Ph), 7.72 (dd, 1 H, H6, C₆H₄, ³J_HH

=

Synthesis of [Pd{K³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C-

(CO₂Me)C₆H₃CH₂NH₂-2,Cl-5}Br] (16). MeO₂CCtCCO₂Me

(0.150 mL, 1.22 mmol) was added to a suspension of complex

C (100 mg, 0.153 mmol) in CH₂Cl₂(20 mL). The resulting

mixture was stirred for 48 h and then filtered through a plug

of MgSO_4.The filtrate was concentrated to ca. 2 mL, and Et₂O

(25 mL) was added. The suspension was filtered, and the solid

was washed with Et₂O (2 ꢀ 5 mL) and air-dried to give complex

16 as a yellow solid. Yield: 103 mg, 0.137 mmol, 45%. Mp:

158 °C. Λ_M(Ω^-1cm²mol^-1) = 0 (5.31 ꢀ 10^-4M). Anal. Calcd

for C₂₅H₂₅BrClNO₁₂Pd (753.232): C, 39.86; H, 3.35; N, 1.86.

Found: C, 39.60; H, 3.23; N, 1.87. IR (cm^-1): ν(NH) 3184, 3286;

=

7.6, ⁴J_HH=1.6 Hz). ¹³C{¹H} NMR (100.81 MHz): δ 48.3 (s, C),

51.4 (s, CH₂Ar), 52.1 (s, OMe), 52.6 (s, OMe), 52.9 (s, OMe),

53.0 (s, OMe), 53.1 (s, CH₂Ph), 53.6 (s, OMe), 56.8 (s, OMe),

128.4 (s, CH), 128.5 (s, CH), 128.8 (s, CH), 129.0 (s, CH), 129.5

(s, CH), 130.4 (s, CH), 132.3 (s, C), 133.3 (s, C), 133.7 (s, C),

136.0 (s, C), 136.6 (s, C), 142.9 (s, C), 149.5 (s, C), 160.6 (s, CO),

162.1 (s, CO), 162.7 (s, CO), 164.5 (s, CO), 173.3 (s, CO), 183.5

(s, CO). Single crystals suitable for an X-ray diffraction study

were obtained by slow diffusion of Et₂O into a solution of 18 in

CH₂Cl₂.

Synthesis of [Pd{K³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C-

(CO₂Me)C₆H₄CH₂CH₂NH₂-2}Br] (19). MeO₂CCtCCO₂Me

1

ν(CO) 1728 vs, 1672 s, 1626 s. H NMR (300 MHz): δ 2.68

Article

Organometallics, Vol. 28, No. 14, 2009 4193

(0.235 mL, 2.00 mmol) was added to a suspension of complex F

(150 mg, 0.250 mmol) in CH₂Cl₂(20 mL). The resulting mixture

was stirred for 70 h and then filtered through a plug of MgSO₄.

The filtrate was concentrated to ca. 2 mL, and Et₂O (25 mL)

was added. The suspension was filtered, and the solid was

washed with Et₂O (2 ꢀ 3 mL) and air-dried to give complex

19 as a bright yellow solid. Yield: 345 mg, 0.471 mmol, 96%.

Mp: 247 °C. Λ_M(Ω^-1cm²mol^-1)=0 (5.10 ꢀ 10^-4M). Anal.

Calcd for C₂₆H₂₈BrNO₁₂Pd (732.814): C, 42.61; H, 3.85;

N, 1.91. Found: C, 42.48; H, 3.70; N, 1.88. IR (cm^-1): ν(NH)

3284 s, 3216 m, 3138 m; ν(CO) 1746 s, 1727 vs, 1666 s, 1644 s. ¹H

NMR (400 MHz): δ 2.25 (m, 1 H, CH₂N), 2.59 (m, 1 H, NH₂),

2.94 (“d”, 1 H, CH₂Ar, ²J_HH=13.6 Hz), 3.10 (m, 1 H, CH₂N),

3.67 (s, 3 H, OMe), 3.75 (s, 3 H, OMe), 3.76 (s, 3 H, OMe), 3.95

(s, 3 H, OMe), 3.98 (s, 3 H, OMe), 4.04 (s, 3 H, OMe), 4.40

(td, 1 H, ²J_HH=³J_HH= 13.2, ³J_HH=4.4 Hz), 7.07-7.16 (m, 2 H,

H3 + H5), 7.25 (td, 1 H, H4, ³J_HH=7.6, ⁴J_HH=0.8 Hz), 7.37

7.38 (d, 1 H, H6, ³J_HH=7.5 Hz). ¹³C{¹H} NMR (75.45 MHz): δ

37.3 (s, CH₂Ar), 43.3 (s, Me), 48.9 (s, C), 52.1 (s, OMe), 52.6

(s, OMe), 52.9 (s, OMe), 53.0 (s, OMe), 53.2 (s, OMe), 55.2

(s, CH₂N), 56.8 (s, OMe), 127.1 (s, CH), 129.6 (s, CH), 130.6 (s,

C), 131.4 (s, CH), 131.6 (s, CH), 133.7 (s, C), 134.1 (s, C), 135.5

(s, C), 135.9 (s, C), 146.3 (s, C), 150.1 (s, C), 160.8 (s, CO), 161.3

(s, CO), 163.4 (s, CO), 164.4 (s, CO), 171.1 (s, CO), 183.4 (s, CO).

Single crystals suitable for an X-ray diffraction study were

obtained by slow diffusion of Et₂O into a solution of 21 in

CHCl₃.

Synthesis of [Pd{K³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C(CO₂-

Me)C₆H₄CH₂NHCH₂Ph-2}(H₂O)]OTf (22). TlOTf (210 mg,

0.593 mmol) was added to a suspension of complex 18 (480 mg,

0.593 mmol) in CH₂Cl₂(20 mL). The resulting mixture was stirred

for 7 h and then filtered through a plug of Celite to remove TlBr.

The filtrate was concentrated to ca. 2 mL, and Et₂O (25 mL) was

added. The suspension was filtered, and the solid was dried under

nitrogen to give complex 22 as a yellow solid. Yield: 425 mg,

0.474 mmol, 80%. Mp: 174-175 °C. Λ_M(Ω^-1cm²mol^-1) = 86

(3.60 ꢀ 10^-4M). Anal. Calcd for C₃₃H₃₄F₃NO₁₆PdS (896.084): C,

44.23; H, 3.82; N, 1.56; S, 3.58. Found: C, 44.64; H, 3.68; N, 2.23; S,

3

(d, 1 H, H6, J_HH= 8.0 Hz). ¹³C{¹H} NMR (100.81 MHz):

δ 39.1 (s, CH₂Ar), 44.8 (s, CH₂N), 48.7 (s, C), 52.1 (s, OMe),

52.6 (s, OMe), 52.9 (s, OMe), 53.0 (s, OMe), 53.0 (s, OMe), 56.8

(s, OMe), 126.8 (s, CH), 129.3 (s, CH), 131.3 (s, CH), 133.5

(s, C), 134.5 (s, C), 135.4 (s, C), 135.8 (s, C), 146.2 (s, C), 150.3

(s, C), 160.1 (s, CO), 161.4 (s, CO), 163.4 (s, CO), 164.3 (s, CO),

171.4 (s, CO), 184.1 (s, CO).

1

3.31. IR (cm^-1): ν(NH) 3145; ν(CO) 1728 vs, 1636 s. H NMR

(300 MHz): δ 1.81 (s, 2 H, H₂O), 3.36 (br d, 1 H, CH₂, ²J_HH

=

14.7 Hz), 3.50 (dd, 1 H, CH₂, ²J_HH= 13.5, ³J_HH= 10.2 Hz), 3.69

(s, 3 H, OMe), 3.78 (s, 3 H, OMe), 3.81 (s, 3 H, OMe), 3.95 (s, 3 H,

OMe), 3.98 (s, 3 H, OMe), 3.99 (s, 3 H, OMe), 4.43 (dd, 1 H, CH₂,

²J_HH= 15.3, ³J_HH=1.8 Hz), 5.60 (m, 1 H, NH), 6.96 (dd, 1 H,

C₆H₄, ²J_HH=7.5, ³J_HH=15 Hz), 7.11-7.33 (m, 7 H, Ph + 2 H of

C₆H₄), 7.69 (dd, 1 H, C₆H₄, ²J_HH=7.8, ⁴J_HH=1.5 Hz). One proton

of CH₂is obscured by the OMe groups. ¹³C{¹H} NMR (75.40

MHz): δ 52.0 (s, CH₂Ar), 52.6 (s, OMe), 52.7 (s, OMe), 53.0 (s,

OMe), 53.2 (s, OMe), 53.3 (s, CH₂Ph), 53.5 (s, OMe), 57.0 (s,

OMe), 119.9 (q, CF₃, ¹J_CF=309.1 Hz), 127.5 (s, CH), 128.3 (s, CH),

128.8 (s, CH), 128.9 (s, CH), 129.0 (s, CH), 129.6 (s, CH), 130.5 (s,

CH), 131.0 (s, C), 133.2 (s, C), 133.8 (s, C), 134.2 (s, C), 137.0 (s, C),

144.2 (s, C), 149.4 (s, C), 160.3 (s, CO), 162.0 (s, CO), 162.8 (s, CO),

164.4 (s, CO), 173.3 (s, CO), 183.3 (s, CO).

Synthesis of [Pd{K³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C-

(CO₂Me)C₆H₄CH₂CMe₂NH₂-2}Cl] (20). MeO₂CCtCCO₂Me

(0.214 mL, 1.79 mmol) was added to a suspension of complex G

(130 mg, 0.224 mmol) in CHCl₃(30 mL). The resulting mixture

was refluxed for 5 h and then filtered through a plug of MgSO₄.

The filtrate was concentrated to ca. 2 mL, and Et₂O (25 mL) was

added. The suspension was filtered, and the solid was washed

with Et₂O (2 ꢀ 3 mL) and air-dried to give complex 20 as a bright

yellow solid. Yield: 204.5 mg, 0.285 mmol, 64%. Mp: 208 °C dec.

Λ

_M(Ω^-1cm²mol^-1)=1 (5.58ꢀ10^-4M). Anal. Calcd for C₂₈-

H₃₂ClNO₁₂Pd (716.412): C, 46.94; H, 4.50; N, 1.96. Found: C,

47.25; H, 4.64; N, 1.97. IR (cm^-1): ν(NH) 3277, 3191, 3124;

ν(CO) 1729 vs, 1667 s, 1640 s. ¹H NMR (400 MHz): δ 0.95 (s,

3 H, Me), 1.62 (s, 3 H, Me), 2.44 (br d, 1 H, NH₂, ²J_HH=10.0

Hz), 2.57 (d, 1 H, CH₂, ²J_HH=13.2 Hz), 3.54 (br d, 1 H, NH₂,

²J_HH= 9.2 Hz), 3.67 (s, 3 H, OMe), 3.75 (s, 3 H, OMe), 3.76 (s, 3

H, OMe), 3.95 (s, 3 H, OMe), 3.97 (s, 3 H, OMe), 4.07 (s, 3 H,

Synthesis of [Pd{K³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C-

(CO₂Me)C₆H₄CH₂NHCH₂Ph-2}(py)]OTf (23). Pyridine (0.02 mL,

0.15 mmol) was added to a suspension of complex 22 (130 mg,

0.145 mmol) in CH₂Cl₂(20 mL). The resulting mixture was stirred

for 23 h and then filtered through a plug of Celite. The filtrate was

concentrated to ca. 2 mL, and Et₂O (25 mL) was added. The

suspension was filtered, and the solid was washed with Et₂O (2 ꢀ

3 mL) and air-dried to give complex 23 as a yellow solid. Yield:

112 mg, 0.117 mmol, 81%. Mp: 225 °C. Λ_M(Ω^-1cm²mol^-1) =

117 (4.20 ꢀ 10^-4M). Anal. Calcd for C₃₈H₃₇F₃N₂O₁₅PdS

(957.171): C, 47.68; H, 3.90; N, 2.93; S, 3.35. Found: C, 47.22;

H, 3.71; N, 2.89; S, 3.36. IR (cm^-1): ν(NH) 3128; ν(CO) 1728 s,

1708 s, 1677 s, 1635 s. ¹H NMR (300 MHz): δ 3.16 (br d, 1 H, CH₂,

2

OMe), 4.24 (d, 1 H, CH₂, J_HH=13.6 Hz), 7.01 (d, 1 H, H3,

³J_HH= 6.8 Hz), 7.09 (t, 1 H, H5, ³J_HH=7.6 Hz), 7.21 (t, 1 H, H4,

³J_HH=7.6 Hz), 7.42 (d, 1 H, H6, ³J_HH= 8.0 Hz). ¹³C{¹H} NMR

(100.81 MHz): δ 27.2 (s, Me), 29.6 (s, Me), 46.3 (s, C), 50.8 (s,

CH₂), 52.2 (s, OMe), 52.6 (s, OMe), 52.8 (s, OMe), 52.9 (s,

OMe), 53.0 (s, OMe), 55.1 (s, CMe₂), 56.7 (s, OMe), 126.5 (s,

CH), 128.3 (s, CH), 131.1 (s, CH), 132.9 (s, CH), 133.5 (s, C),

133.9 (s, C), 134.0 (s, C), 135.9 (s, C), 146.3 (s, C), 150.3

(s, C), 160.1 (s, CO), 161.4 (s, CO), 163.5 (s, CO), 164.4 (s,

CO), 172.1 (s, CO), 183.6 (s, CO).

2

²J_HH=10.8 Hz), 3.66 (br t, 1 H, CH₂, J_HH=³J_HH=11.4 Hz,

Synthesis of [Pd{K³(O,C,N)-OdC(OMe){C₅(CO₂Me)₄}C-

(CO₂Me)C₆H₄CH₂CH₂NHMe-2}Cl] (21). MeO₂CCtCCO₂-

Me (0.400 mL, 2.97 mmol) was added to a suspension of

complex 1 (150 mg, 0.234 mmol) in acetone (20 mL). The

resulting mixture was refluxed for 8 h and then filtered through

a plug of MgSO₄. The filtrate was concentrated to ca. 3 mL, and

Et₂O (25 mL) was added. The suspension was filtered, and the

solid was washed with Et₂O (2 ꢀ 5 mL) and air-dried to give

complex 21 as a yellow-orange solid. Yield: 296 mg, 0.396 mmol,

85%. Mp: 188 °C. Λ_M(Ω^-1cm²mol^-1) = 0 (5.36ꢀ10^-4M).

Anal. Calcd for C₂₇H₃₀BrNO₁₂Pd (746.836): C, 43.42; H, 4.05;

N, 1.87. Found: C, 43.41; H, 4.23; N, 1.69. IR (cm^-1): ν(NH)

3248; ν(CO) 1764 s, 1722 vs, 1665 s, 1639 s. ¹H NMR (300 MHz):

δ 2.07 (m, 1 H, CH₂N), 2.69 (br d, 3 H, Me, ³J_HH=3.9 Hz), 2.93

(d, 1 H, CH₂Ar, ²J_HH=13.2 Hz), 3.04 (m, 2 H, NH + 1 H of

CH₂N), 3.67 (s, 3 H, OMe), 3.76 (s, 3 H, OMe), 3.80 (s, 3 H,

OMe), 3.95 (s, 3 H, OMe), 3.97 (s, 3 H, OMe), 4.07 (s, 3 H, OMe),

partially obscured by OMe), 3.71 (s, 3 H, OMe), 3.82 (s, 3 H, OMe),

3.83 (s, 3 H, OMe), 3.90 (s, 3 H, OMe), 3.97 (s, 3 H, OMe), 3.98 (s, 3

H, OMe), 4.01 (m, 1 H, CH₂), 4.72 (“d”, 1 H, CH₂, ²J_HH=15.3 Hz),

5.87 (br d, 1 H, NH, ³J_HH= 9.9 Hz), 7.17-7.34 (m, 8 H, aromatic),

7.47 (m, 2 H, aromatic), 7.66 (m, 2 H, aromatic), 7.89 (m, 2 H,

aromatic). ¹³C{¹H} NMR (75.40 MHz): δ 45.2 (s, C), 52.5 (s,

OMe), 52.8 (s, OMe), 53.1 (s, OMe), 53.2 (s, OMe), 54.0 (s, OMe),

55.4 (s, CH₂), 56.6 (s, OMe), 58.0 (s, CH₂), 120.6 (q, CF₃, ¹J_CF

=

320.0 Hz), 125.3 (s, CH), 127.0 (s, CH), 128.3 (s, CH), 128.5 (s,

CH), 128.7 (s, CH), 128.8 (s, CH), 129.0 (s, CH), 130.4 (s, CH),

131.1 (s, C), 133.5 (s, C), 134.5 (s, C), 135.6 (s, C), 136.7 (s, C), 138.3

(s, CH), 140.0 (s, C), 144.8 (s, C), 150.8 (s, CH), 151.8 (s, C), 160.2

(s, CO), 162.9 (s, CO), 163.2 (s, CO), 164.6 (s, CO), 175.9 (s, CO),

183.7 (s, CO).

Synthesis of Complex 24. MeCtCMe (0.60 mL, 97.65 mmol)

was added to a solution of complex A (350 mg, 0.457 mmol) in

CH₂Cl₂(25 mL), and the resulting solution was stirred for 72 h.

Decomposition to metallic palladium was observed. The mix-

ture was filtered through a plug of MgSO₄, the filtrate was

3

4.83 (m, 1 H, CH₂Ar), 7.12 (t, 1 H, H5, J_HH=7.5 Hz), 7.15

(d, 1 H, H3, J_HH=7.2 Hz), 7.28 (t, 1 H, H4, J_HH=7.2 Hz),

3

4194 Organometallics, Vol. 28, No. 14, 2009

Vicente et al.

Table 1. Crystal Data and Structure Refinement Details for Complexes 2, 5a, 6b, 7a, 7b 3DMSO, and 9

3

7b 3DMSO

2

5a

6b

7a

9

3

formula

fw

C₂₇H₂₇BrNPPd

582.78

colorless needle

C₄₂H₃₇BrNO₂PPd C₃₀H₃₃BrN₂O₂Pd C₁₉H₂₇BrClNPd

639.89

colorless prism

C₄₁H₄₅BrClNO₃PdS₃C₁₉H₂₇BrN₂O₂Pd

501.74

805.01

colorless prism

491.18

pale yellow tablet yellow block

917.72

cryst habit

cryst size (mm)

temp (K)

cryst syst

space group

yellow prism

0.74 ꢀ 0.36 ꢀ 0.11

298(2)

monoclinic

P2₁/n

0.25 ꢀ 0.06 ꢀ 0.06 0.25 ꢀ 0.24 ꢀ 0.13 0.15 ꢀ 0.12 ꢀ 0.12 0.68 ꢀ 0.54 ꢀ 0.48 0.16 ꢀ 0.14 ꢀ 0.09

100(2)

monoclinic

C2/c

17.8657(14)

9.8283(8)

27.055(2)

90

95.424(2)

90

4729.4(6)

8

1.637

100(2)

triclinic

P1

173(2)

triclinic

P1

173(2)

triclinic

P1

100(2)

monoclinic

P2₁/n

˚

a (A)

9.9354(4)

12.0519(5)

15.1563(6)

91.814(2)

103.419(2)

91.669(2)

1763.15(12)

2

9.2820(4)

11.3665(5)

14.9421(7)

89.506(2)

78.929(2)

70.892(2)

1459.37(11)

2

9.0673(16)

9.845(2)

11.943(3)

60.795(14)

78.532(18)

84.997(14)

980.3(4)

2

15.5782(8)

14.7696(7)

18.0154(9)

90

9.9636(5)

9.2661(9)

22.0259(11)

90

˚

b (A)

˚

c (A)

R (deg)

β (deg)

γ (deg)

106.739(2)

90

95.936(3)

90

3

˚

V (A )

Z

F

3969.4(3)

4

1.536

2022.6(2)

4

1.648

_calcd(Mg m^-3

)

1.516

1.742

816

1.456

2.032

648

1.664

3.120

492

μ(Mo, KR) (mm^-1

F(000)

)

2.557

2336

1.738

1872

2.907

1008

θ range (deg)

no. rflns collected

no. indep rflns

R_int

2.29-28.16

26 642

5481

0.0402

0.8617, 0.5673

2.11-28.23

20 685

7917

1.90-28.24

17 030

6555

3.01-25.00

6623

3371

0.0195

0.963, 0.700

168/212

1.129

0.0245

0.0651

0.493

1.82-28.19

44 814

9187

0.0350

0.8592, 0.7496

1/489

3.01-25.00

4404

3518

0.0169

0.0245

0.0151

max, min transmsn

no. of restraints/params 0/285

0.8052, 0.6699

0/438

1.062

0.0226

0.0600

0.393

0.7925, 0.7503

0/332

1.046

0.0296

0.0709

0.529

0.970, 0.640

194/234

1.037

0.0272

0.0593

0.333

goodness of fit on F²

R1 (I > 2σ(I))

wR2 (all rflns)

1.136

1.065

0.0392

0.0812

0.754

0.0333

0.0760

0.818

-3

˚

largest diff peak (e A

)

4

3

concentrated to ca. 2 mL, and Et₂O (25 mL) was added. The

suspension was filtered, and the solid was washed with Et₂O (2 ꢀ

5 mL), air-dried, and recrystallized from CH₂Cl₂/Et₂O to give

complex 24 as a yellow solid. Yield: 138.2 mg, 0.145 mmol, 32%.

Mp: 164 °C. Λ_M(Ω^-1cm²mol^-1) = 0 (5.40 ꢀ 10^-4M). Anal.

Calcd for C₅₂H₆₂Br₂N₂Pd (981.290): C, 63.65; H, 6.37; N, 2.85.

Found: C, 62.99; H, 6.48; N, 2.79. IR (cm^-1): ν(NH) 3230.

¹H NMR (400 MHz): δ 0.92 (s, 3 H, Me), 1.46 (s, 6 H, Me), 1.53

(s, 6 H, Me), 3.95 (m, 2 H, CH₂Ar), 4.02 (br s, 2 H, CH₂Ph), 5.12

(s, 1 H, =CH₂), 5.15 (s, 1 H, =CH₂), 6.60 (dd, 1 H, H6,

³J_HH= 7.6, J_HH= 1.2 Hz), 7.11 (td, 1 H, H4, J_HH= 7.2,

⁴J_HH=1.2 Hz), 7.16 (td, 1 H, H5, ³J_HH=7.2, ⁴J_HH=1.2 Hz), 7.22

3

4

(dd, 1 H, H6, J_HH= 7.6, J_HH=1.2 Hz). The protons of

coordinated water are obscured by the Me groups. ¹³C{¹H}

NMR (100.81 MHz): δ 11.0 (s, Me), 11.5 (s, Me), 13.6 (s, Me),

14.2 (s, Me), 14.9 (s, Me), 27.9 (s, CMe₂), 29.2 (s, Me), 30.1 (s,

CMe₂), 47.1 (s, C-Pd), 53.3, (s, CH₂), 54.3 (s, CMe₂), 61.8 (s, C),

71.8 (s, C), 120.0 (q, CF₃, ¹J_CF= 319.4 Hz), 126.3 (s, CH, C4),

127.1 (s, CH, C5), 127.9 (s, CH, C6), 131.6 (s, C2), 133.6 (s, CH,

C3), 136.2 (s, C), 141.0 (s, C), 144.7 (s, C1). Single crystals

suitable for an X-ray diffraction study were obtained by slow

evaporation of a solution of 25 in CHCl₃.

Single Crystal X-ray Structure Determinations. Relevant crys-

tallographic data and details of the refinements for the structures

of complexes 2, 5a, 6b, 7a, 7b 3DMSO, 9, 14a 2DMSO, 18, 21,

24, and 25 are given in Tables 1 and 2. Data Collection. Crystals

suitable for X-ray diffraction were mounted in inert oil on a glass

fiber and transferred to Siemens P4 (7a, 9, 24) or Bruker SMART

diffractometers (2, 5a, 6b, 7b 3DMSO, 14a 2DMSO, 18, 21, 25).

4

3

³J_HH= 7.6, J_HH= 1.2 Hz), 6.94 (td, 1 H, H5, J_HH=7.6,

⁴J_HH= 1.2 Hz), 7.07 (td, 1 H, H4, ³J_HH= 7.6, ⁴J_HH= 1.2 Hz),

7.38-4.43 (m, 3 H, Ph), 7.85 (dd, 1 H, H3, ³J_HH= 7.6, ⁴J_HH

=

1.2 Hz), 9.35 (br s, NH). ¹³C{¹H} NMR (75.45 MHz): δ 10.4 (s,

Me), 11.0 (s, Me), 19.2 (s, Me), 46.9 (s, CH₂Ar), 50.4, (s,

CH₂Ph), 61.8 (s, C), 118.0 (s, =CH₂), 127.0 (s, C2), 127.2

(s, CH, C4), 127.4 (s, CH, C6), 127.6 (s, CH, C5), 129.1 (s, m-

CH, Ph), 129.6 (s, p-CH, Ph), 129.9 (s, i-C, Ph), 130.1 (s, CH,

C3), 131.0 (s, o-CH, Ph), 136.3 (s, C), 139.1 (s, C), 142.2 (s, C1),

148.2 (s, CdCH₂). Single crystals suitable for an X-ray diffrac-

tion study were obtained by slow evaporation of a saturated

solution of 24 in n-hexane.

3

Data were recorded at 298(2) K (9), 173(2) K (6b, 7a, 18, 24), or

100(2)K (2, 5a, 7b 3DMSO, 14 2DMSO, 21, 25), using graphite-

monochromated Mo KR radiation (λ = 0.71073 A) and ω-scan

mode. Multiscan (2, 5a, 6b, 7b 3DMSO, 14a 2DMSO, 18,

3

˚

Synthesis of Complex 25. TlOTf (195.0 mg, 0.550 mmol) was

added to a solution of complex G (160.0 mg, 0.258 mmol) in

acetone (20 mL), and the mixture was stirred for 15 min.

MeCtCMe (0.130 mL, 1.66 mmol) was added, and the resulting

suspension was further stirred for 24 h and then filtered through

a plug of MgSO₄. The solvent was evaporated, the residue was

dissolved in CH₂Cl₂(2 mL), and n-hexane (20 mL) was added.

The mixture was kept at 0 °C for 12 h. The resulting yellow cry-

stals were separated by filtration and air-dried to give complex

25 as a yellow solid. Yield: 127.0 mg, 0.217 mmol, 42%. Mp:

90 °C. Anal. Calcd for C₂₃H₃₄F₃NO₄SPd (583.986): C, 47.30; H,

5.87; N, 2.40; S, 5.49. Found: C, 47.37; H, 6.13; N, 2.42; S, 5.35.

3

21, 25) or psi-scan (7a, 9, 24) absorption corrections were

applied. Structure Solution and Refinements. Structures were

solved by the heavy-atom method (7a, 9, 24, 25) or by direct

methods (2, 5a, 6b, 7b 3DMSO, 14 2DMSO, 18, 21) and all non-

3

hydrogen atoms refined anisotropically on F²using the program

SHELXL-97.⁷⁴Hydrogen atoms were refined as follows: Com-

plexes 2, 5a, 6a, and 21: NH, free; methyl, rigid group; all others,

riding. Complexes 7a and 18: methyl, rigid group; all others,

riding. Complex 7b 3DMSO: NH, free; ordered methyls, rigid

group; all others, riding. Complex 14a 2DMSO: NH₂, free with

3

DFIX; methyl, rigid group; all others, riding. Complex 25: H₂O

and NH₂, free with SADI; methyl, rigid group; all others, riding.

Complexes 9 and 24: all hydrogen atoms were refined using

a riding model. Special features: Complex 6a: The CO₂Et group

is disordered over two positions with a ca. 60:40 occupancy

1

IR (cm^-1): ν(OH) 3505 vs, 3424 vs; ν(NH) 3321 s, 3262 s. H

NMR (400 MHz): δ 0.67 (s, 3 H, Me), 1.04 (s, 3 H, CMe₂), 1.30

(s, 3 H, Me), 1.55 (s, 3 H, CMe₂), 1.77 (s, 3 H, Me), 1.86 (s, 3 H,

Me), 1.91 (s, 3 H, Me), 2.16 (s, 3 H, Me), 2.40 (br s, 1 H, NH₂),

2

2.54 (d, 1 H, CH₂, J_HH= 13.6 Hz), 4.03 (br d, 1 H, J_HH=

9.6 Hz), 4.35 (d, 1 H, CH₂, ²J_HH=13.6 Hz), 6.99 (dd, 1 H, H3,

(74) Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, 64, 112.

Article

Organometallics, Vol. 28, No. 14, 2009 4195

Table 2. Crystal Data and Structure Refinement Details for Complexes 14a 2DMSO, 18, 21, 24, and 25

3

14a 2DMSO

18

21

24

25

3

formula

fw

C

₄₄H₆₆Br₂F₂N₂O₄Pd₂S₂

C₃₂H₃₂BrNO₁₂Pd

808.90

yellow tablet

0.36 ꢀ 0.12 ꢀ 0.05

173(2)

monoclinic

P2₁/c

10.7468(10)

14.673(2)

20.083(3)

90

92.769(10)

90

3163.1(7)

4

1.699

C₂₇H₃₀BrNO₁₂Pd

746.83

yellow lath

C₅₂H₆₂Br₂N₂Pd₂

981.26

orange block

0.62 ꢀ 0.44 ꢀ 0.23

173(2)

orthorhombic

Pccn

23.944(3)

10.0822(11)

21.529(2)

90

C₂₃H₃₄F₃NO₄PdS

583.97

yellow lath

0.28 ꢀ 0.27 ꢀ 0.07

100(2)

monoclinic

P2₁/c

9.4888(4)

13.1517(6)

19.8206(9)

90

94.431(2)

90

2466.10(19)

4

1.573

1161.73

pale yellow needle

0.17 ꢀ 0.04 ꢀ 0.03

100(2)

triclinic

P1

10.1790(6)

11.4544(7)

11.6891(7)

106.439(2)

103.292(2)

104.686(2)

1195.76(12)

1

cryst habit

cryst size (mm)

temp (K)

cryst syst

space group

0.27 ꢀ 0.18 ꢀ 0.08

100(2)

monoclinic

P2₁/n

˚

a (A)

9.5423(4)

17.9781(8)

17.2768(8)

90

102.774(2)

90

2890.5(2)

4

1.716

2.089

1504

˚

b (A)

˚

c (A)

R (deg)

β (deg)

γ (deg)

90

3

˚

V (A )

Z

F

5197.2(10)

4

1.254

1.927

2016

_calcd(Mg m^-3

)

1.613

2.559

588

μ(Mo, KR) (mm^-1

F(000)

)

1.917

1632

0.889

1200

θ range (deg)

no. rflns collected

no. indep rflns

R_int

1.92-28.17

13 910

5379

1.72-28.32

20 956

7810

2.25-26.73

32 369

6144

3.18-25.00

4720

4482

1.86-28.21

28 345

5686

0.0409

0.0653

0.0344

0.0400

0.0279

max, min transmsn

no. of restraints/params

goodness of fit on F²

R1 (I > 2σ(I))

0.9272, 0.8304

2/276

1.102

0.0464

0.0904

0.802

0.9999, 0.8331

8/434

1.036

0.0503

0.0949

0.635

0.8507, 0.6023

0/390

1.273

0.0403

0.0857

1.163

0.898, 0.727

256/259

0.882

0.0523

0.1188

0.688

0.9404, 0.7889

2/322

1.130

0.0276

0.0648

0.511

wR2 (all rflns)

largest diff peak (e A

-3

˚

)

ꢀ

Acknowledgment. We thank Ministerio de Educacion

y Ciencia (Spain), FEDER (CTQ2007-60808/BQU), and

distribution. 7b 3DMSO: One of the DMSO is disordered over

two positions with a ca. 77:23 occupancy distribution. 24: Sol-

3

vent-accessible voids of 208.0 A, were found in the crystal

˚

ꢀ

Fundacion Seneca (04539/GERM/06) for financial support.

C.R.A. thanks Consolider Ingenio 2010 (CSD2007-00006)

and Generalitat Valenciana (GV07/087) for financial

support.

structure of 24, arranged into channels along the b axis (program

PLATON-SQUEEZE).⁷⁵The maximum residual electron den-

sityis0.69e A,^-3, and nodefinite solvent moleculecould be found

˚

in the void area. No hydrogen bond acceptor was found for the

N-H group of 24.

Supporting Information Available: ¹H NMR tables for the

new compounds, details (including symmetry operators) of

hydrogen bondings, and listing of all refined and calculated

atomic coordinates, anisotropic thermal parameters, bond

lengths and angles, and CIF files for compounds 2, 5a, 6b, 7a,

7b 3DMSO, 9, 14a 2DMSO, 18, 21, 24, and 25. This mate-

The programs use neutral atom scattering factors, Δf ⁰and

Δf ⁰⁰and absorption coefficients from International Tables for

Crystallography.⁷⁶

(75) Spek, A. L. J. Appl. Crystallogr. 2003, 36, 7.

(76) International Tables for Crystallography; Kluwer Academic Pub-

lishers: Dordrecht, The Netherlands, 1992; Vol. C, Tables 6.1.1.4 (pp

500-502), 4.2.6.8 (pp 219-222), and 4.2.4.2 (pp 193-199)

3

rial is available free of charge via the Internet at http://

pubs.acs.org.

Article Doi

Insertion of one, two, and three molecules of alkyne into the Pd-C bond of ortho-palladated primary and secondary arylalkylamines

DOI: 10.1021/om9002895

Source and publish data:

Authors:

Article abstract of DOI:10.1021/om9002895

Full text of DOI:10.1021/om9002895

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