From chelate C,N-cyclopalladated oximes to C,N,N′-, C,N,S -, or C,N,C′-pincer palladium(II) complexes by formation of oxime ether ligands

Article abstract of DOI:10.1021/om3007213

Pincer complexes of the types [Pd{C,N,N′-Ar{C(Me)=NOCH ₂py-2}-2}X] or [Pd{C,N,S-C₆H₄{C(Me)=NOCH ₂SMe}-2}Cl] (Ar = C₆H₄, C₆H(OMe) ₃-4,5,6; py-2 = 2-pyridyl; X = Cl, Br) have been prepared by reacting cyclopalladated oxime complexes [Pd{C,N-Ar{C(Me)=NOH}-2}(μ-Cl)]₂ with XCH₂py-2 or ClCH₂SMe, respectively, in the presence of K^tBuO. Various neutral and cationic derivatives have been synthesized as well as iminobenzoyl complexes resulting from the insertion of isocyanide into their Pd-C_aryl bond. The cycloaddition of MeO ₂CC≡CCO₂Me to the oximato complex [Pd{C,N-C ₆H₄{C(Me)=NO}-2}(^tBubpy)] (^tBubpy = 4,4′-di-tert-butyl-2,2′-bipyridine) in the presence of various neutral L ligands produces pincer complexes [Pd{C,N,C′-C₆H ₄{C(Me)=NOC(CO₂Me)=C(CO₂Me)}-2}L]. Complexes of each one of the new types have been characterized by X-ray diffraction methods.

Full text of DOI:10.1021/om3007213

Article
pubs.acs.org/Organometallics
From Chelate C,N-Cyclopalladated Oximes to C,N,N′-, C,N,S-, or
C,N,C′-Pincer Palladium(II) Complexes by Formation of Oxime Ether
Ligands
Antonio Abellan-Lopez,† María-Teresa Chicote,† Delia Bautista,‡ and Jose Vicente*,†
́
́
́
†Grupo de Química Organometal
Spain
́
ica, Departamento de Química Inorgan
́
ica, Universidad de Murcia, Apartado 4021, 30071 Murcia,
‡SAI, Universidad de Murcia, Apartado 4021, 30071 Murcia, Spain
S
* Supporting Information
ABSTRACT: Pincer complexes of the types [Pd{C,N,N′-Ar{C(Me)
NOCH2py-2}-2}X] or [Pd{C,N,S-C6H4{C(Me)NOCH2SMe}-2}Cl] (Ar
= C6H4, C6H(OMe)3-4,5,6; py-2 = 2-pyridyl; X = Cl, Br) have been prepared
by reacting cyclopalladated oxime complexes [Pd{C,N-Ar{C(Me)NOH}-
2}(μ-Cl)]2 with XCH2py-2 or ClCH2SMe, respectively, in the presence of
KtBuO. Various neutral and cationic derivatives have been synthesized as well
as iminobenzoyl complexes resulting from the insertion of isocyanide into
their Pd−Caryl bond. The cycloaddition of MeO2CCCCO2Me to the
oximato complex [Pd{C,N-C6H4{C(Me)NO}-2}(tBubpy)] (tBubpy = 4,4′-di-tert-butyl-2,2′-bipyridine) in the presence of
various neutral L ligands produces pincer complexes [Pd{C,N,C′-C6H4{C(Me)NOC(CO2Me)C(CO2Me)}-2}L].
Complexes of each one of the new types have been characterized by X-ray diffraction methods.
applying this strategy, namely, the nucleophilic attack of
oximato chelate complexes to XCH2py-2 (X = Cl, Br; py-2 =
2-pyridyl) or ClCH2SMe to give C,N,N′- or C,N,S-pincer
derivatives, respectively. We have reported a different, but
related, approach when reacting a 2-formylaryl palladium
complex with ortho-phenylenediamine.28 The same type of
condensation reaction has been used to prepare chelate29 or
pincer palladium complexes from monocoordinated formylaryl
complexes and primary amines.30 Very recently,31 the
formation of the pincer complexes [MCl{P,C,P-C-
(PPh2CH2PPh2)2] (M = Ni, Pd, Pt) from MCl2, CS2, and
dppm has been suggested to occur by attack of dppm to chelate
complexes of the type [M]{P,C-C(S)PPh2CH2PPh2)2} with
abstraction of dppmS.
We are studying the reactivity of ortho-substituted aryl
palladium complexes with alkynes. These reactions generally
give organic compounds4,5,7,8,11,32−34 or products resulting
from the insertion of the alkyne into the Pd−C
bond3,8,11,12,32−36 or its attack on the aryl ligand.4,8,17,32,37
The latter are most probably obtained through the
intermediacy of insertion products, with only one exception,
in which the alkyne attacks to an aryl substituent.17 In this
work, we report the unprecedented reaction of an aryl complex
with MeO2CCCCO2Me (DMAD). When reacted with this
alkyne, aryl palladium complexes typically give the product of
insertion into the Pd−C bond.2,9,11,12,34,36,38 However, the
reaction with some of our oximato complexes afforded the
INTRODUCTION
■
Ortho-functionalized aryl palladium complexes are of interest
because of their remarkable reactivity.1,2 In particular, we have
focused our ongoing research on such complexes3−7 in the
study of their reactions with unsaturated species. The modified
reactivity imposed by the metal on both the pre-existing ortho
group and that resulting from the insertion process allowed us
to prepare interesting organic compounds resulting from
depalladation processes,4,5,8−12 as well as various types of
chelate13,14 and pincer12,15−17 complexes, including the first
family of stable Pd(IV) pincer complexes prepared by oxidizing
the corresponding Pd(II) derivatives18,19 and the first C,N,C-
imidocarbene14 and C,N,O-acyl14,15 complexes of any metal.
The continuous growth in the development of pincer
complexes15−17,20 can be attributed to their applications in
organic synthesis, as catalysts12,18,21 or in stoichiometric
reactions,19,22 or as materials.23 Although the most common
complexes involve symmetrical pincer ligands, the presence of
different donor groups provides unsymmetrical pincer com-
plexes with unique properties and reactivity.24
A few examples have been reported of chelate organometal
complexes converting into pincer derivatives. However, in all
cases, this transformation occurs as a consequence of the
chelating ligand bearing a pendant aryl group that metal-
ates.25,26 In a few other reports, preexisting pendant groups
different from aryl in the chelating ligand have been suggested
to participate in chelate-to-pincer complex conversion
processes.18,26,27 However, the generation of a coordinating
side arm on a chelate complex giving rise to a pincer complex is
unprecedented. We report here the first results obtained
Received: July 29, 2012
Published: October 11, 2012
© 2012 American Chemical Society
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products of a cycloaddition (A, Scheme 1). This behavior
differs also from the typical behavior of ketoximes
acetone or CH2Cl2 (5a4) and, when using silver salts, protected
from light.
The mononuclear acetato complex 7a (Scheme 2) was
prepared from equimolar amounts of 3aCl and AgAcO, while
the dinuclear bridging acetato complex 8a was isolated from the
reaction of 3aCl with AgTfO and AgAcO in 2:1:1 molar ratio.
The latter is the first complex in which two palladium atoms are
connected only by a bridging acetato ligand.
Scheme 1
The reaction of complex 3aCl with excess isocyanide RNC
caused its insertion in the Pd−Caryl bond to give the
iminobenzoyl pincer complex 9a1 (R = Xy; Scheme 3) or
t
9a2 (R = Bu). A similar reaction starting from the cationic
complex 5a1 or 5a2 produced the cationic iminoacyl-
t
(isocyanide) complex 10a1 (R = Xy) or 10a2 (R = Bu),
respectively. Complex 11a1, the analogue of 10a1 containing
the C,N,S-pincer ligand, was prepared in high yield from the
acetonitrile complex 6a4 and XyNC. However, this procedure
t
did not allow us to isolate pure its BuNC homologue 11a2.
t
This complex deinserts BuNC in solution at room temper-
ature, giving a mixture of 6a2 and 11a2. However, pure 11a2
was obtained by reacting the isocyanide complex 6a2 with
tBuNC. Excess isocyanide over the required amount was used
in all these insertion reactions (see Experimental Section), but a
larger excess was necessary to complete the reaction (1) when
tBuNC was used instead of XyNC and (2) when the insertion
occurred in a neutral complex (for example, 3aCl to give 9)
than in a cationic derivative (for example, 5 or 6 to give
complex 10 or 11, respectively). This confirms that the
insertion process is facilitated by the presence of an electron-
withdrawing substituent in the isocyanide and of a higher
positive charge at the metal, both favoring the nucleophilic
attack of the aryl carbon on the isocyanide one.
The reaction of complex 2a with DMAD was carried out in
the hope that, apart from the common insertion of the alkyne
in the Pd−Caryl bond, two alternative processes, namely, a
hydro-oximation or a cycloaddition, could occur. The former
would be analogous to that observed in the reaction of
ketoximes RR′CNOH with DMAD in the presence of
catalytic amounts of base to give compounds (E+Z)-
MeO2CCHC(ONCRR′)CO2Me (B, Scheme 1), which,
under heating, transform into pyrroles,39 while the latter could
afford C in a similar way to that observed in the attack of
DMAD to 1,2-dihydroquinazoline 3-oxide (D, Scheme 1).40
However, the reaction of 2a with an equimolar amount of
DMAD produced a mixture from which complex 12 was the
only product that we could isolate pure, in 52% yield (Scheme
4). Although the NMR spectra and elemental analyses of 12
showed that it was an adduct, they did not allow us to fully
determine its structure. With the purpose of knowing if the
oximato function had participated in the process, we reacted 12
with ClCH2py-2. The reaction produced complex 13, resulting
RR′CNOH when reacted with DMAD in the presence of
catalytic amounts of base. The products are the result of a
hydro-oximation reaction, (E+Z)-MeO2CCHC(ON
CRR′)CO2Me (B, Scheme 1), that convert upon heating into
pyrroles.39 When designing this reaction, we also considered
the possibility that a different cycloaddition occurred to give C
(Scheme 1), taking into account the formation of D in the
reaction of DMAD with 1,2-dihydroquinazoline 3-oxide.40
RESULTS AND DISCUSSION
■
Synthesis. We have previously reported the synthesis of
cyclopalladated aryloxime complexes 1 (Scheme 2) and their
reactions with base to give oximato derivatives, for instance 2.13
We decided to study the potential reactivity of these oximato
complexes toward XCH2py-2 (X = Cl, Br) or ClCH2SMe in the
hope that an oxime ether would form, giving a C,N,N′- or
C,N,S-pincer complex after coordination of the N or S atom.
The results were as expected, and complex 3aBr was obtained
when BrCH2py-2 (prepared in situ from the commercially
available (BrCH2pyH-2)Br and KtBuO) was reacted with 2a
(Scheme 2). However, a more straightforward method for
obtaining good yields of pincer complexes was the reaction of
the oxime complexes 1 with 1 equiv of base and an appropriate
alkyl halide, such as XCH2py-2 or ClCH2SMe, which afforded
complexes 3 or 4, respectively.41
t
from replacement of Bubpy by ClCH2py-2, which we could
isolate in good yield and fully characterize including its crystal
structure. Therefore, formation of 12 can be explained by the
nucleophilic attack of the oximate oxygen on one alkyne carbon
of DMAD followed by the attack of the resulting carbanion on
the Pd atom, which must be more electrophilic than the CN
carbon atom. Complex 12 can be a tetra- (as represented in
Scheme 4) or pentacoordinated complex depending on the role
Replacement of the chloro ligand in complex 3aCl or 4aCl
by monodentate neutral ligands was achieved by reacting them
with equimolar amounts of MClO4 (M = Ag, Na (for 5a3))
and the appropriate ligand to give cationic complexes 5a1−5a4
or 6a1−6a4, respectively. The reactions were carried out in
t
of the ligand Bubpy in the complex. Complex 12 reacted also
t
with isocyanides RNC (R = Xy, Bu; 1:1 molar ratio), at room
temperature, to give complexes 14 and 15, respectively, which
were isolated in moderate yield. In the case of 15, the yield
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Scheme 2
improves when using excess isocyanide. Not even traces of
iminobenzoyl derivatives were obtained when 14 or 15 was
treated with excess isocyanide. In fact, 14 did not react with
tBuNC under any reaction conditions, and this was also the
case for 15 and XyNC below 60 °C, while, upon heating at 80
°C, an intractable mixture formed along with elemental
palladium.
X-ray Crystal Structures. The crystal structures of
complexes 3aBr (Figure 1), 3bCl (Figure 2), 5a3 (Figure 3),
6a1 (Figure 4), 8a·CH2Cl2 (Figure 5), 9a1 (Figure 6), and 13
(Figure 7) have been determined by X-ray diffraction studies,
offering the first structural data for each of the various types of
complexes here described since no derivatives of these pincer
ligands have been reported so far for any metal. In all cases the
palladium atom is in a slightly distorted square-planar
environment.
In the pincer ligands, the five-membered palladacycles are
planar, the highest mean deviation from the plane in all
complexes being 0.0434 Å (in 5a3), while the six-membered
palladacycle adopts an envelope conformation except in
complex 9a1, which displays a boat−boat conformation in
both six-membered metallacycles.
The Pd(1)−C(1), Pd(1)−N(1), N(1)−O(1), and N(1)
C(7) bond distances in our complexes are within the values
found in the few other crystal structures of palladacycles
derived from aryloximes.43 As expected, the formation of the
O(1)−C(9) bond causes an appreciable weakening of the N−
O bond (N(1)−O(1) bond distance within 1.3987(15) and
1.4116(19) Å) compared to that in the only cyclopalladated
aryloximato complex reported so far (1.301(2) Å).13
Complexes 4a, 5a3, 6a3, 7a, 9a1, and 10a1 crystallized with
various amounts of water in spite of being heated in a vacuum
oven. The water content deduced from their elemental analyses
1
was confirmed in all cases by their H NMR spectra.
The reaction of 3bCl with CO, aimed to produce the
corresponding acyl complex, did not occur at room temper-
ature in toluene, and when the reaction mixture was heated at
80 °C for 3 h, decomposition was observed. After removing the
colloidal palladium by filtration through a short pad of
anhydrous MgSO4, a solution was obtained containing the
previously unreported ligand C6H2{C(Me)NOCH2py-2}-
(OMe)3-3,4,5 (L) along with very small amounts of unknown
1
impurities. L was identified by its exact mass and H and 13C
NMR spectra.42 An attempt to prepare L by alkylation of the
oxime C6H2{C(Me)NOH}(OMe)3-3,4,5 with (ClCH2pyH-
2)Cl and KtBuO (1:1:2), carried out under the same reaction
conditions used for the synthesis of 3bCl, produced a mixture
containing only a small amount of L (<20%), along with
unreacted oxime, ClCH2py-2, and other unidentified products.
In complex 8a·CH2Cl2 the two half-molecules are oriented
anti with respect to each other, allowing some interaction
between both palladiums since the Pd(1)−Pd(2) bond
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Scheme 3
Figure 1. Thermal ellipsoid representation plot (50% probability) of
complex 3aBr. Selected bond lengths (Å) and angles (deg): Pd(1)−
C(1) 1.9961(18), Pd(1)−N(1) 2.0034(14), Pd(1)−N(2) 2.1506(15),
Pd(1)−Br(1) 2.4184(3), C(2)−C(7) 1.461(3), N(1)−C(7) 1.292(2),
N(1)−O(1) 1.3990(19), C(9)−O(1) 1.447(2), C(9)−C(10)
1.504(2), N(2)−C(10) 1.351(2); C(1)−Pd(1)−N(1) 79.74(7),
N(1)−Pd(1)−N(2) 91.51(6), C(1)−Pd(1)−Br(1) 94.89(5), N(2)−
Pd(1)−Br(1) 93.98(4), N(1)−C(7)−C(2) 111.46(15), C(7)−N(1)−
O(1) 115.67(14), N(1)−O(1)−C(9) 108.84(12), O(1)−C(9)−
C(10) 112.83(14).
Scheme 4
Figure 2. Left: Thermal ellipsoid representation plot (50%
probability) of complex 3bCl. Right: Intermolecular C−H···O and
C−H···Cl bonds in 3bCl giving layers parallel to the ac plane. Selected
bond lengths (Å) and angles (deg): Pd(1)−C(1) 2.024(2), Pd(1)−
N(1) 1.9923(17), Pd(1)−N(2) 2.1483(18), Pd(1)−Cl(1) 2.3031(5),
C(2)−C(7) 1.465(3), N(1)−C(7) 1.290(3), N(1)−O(1) 1.405(2),
O(1)−C(9) 1.441(3), C(9)−C(10) 1.504(3), N(2)−C(10) 1.347(3);
N(1)−Pd(1)−C(1) 79.51(8), N(1)−Pd(1)−N(2) 91.17(7), C(1)−
Pd(1)−Cl(1) 99.79(6), N(2)−Pd(1)−Cl(1) 90.10(5), N(1)−C(7)−
C(2) 111.90(18), C(7)−N(1)−O(1) 115.52(17), N(1)−O(1)−C(9)
109.40(15), O(1)−C(9)−C(10) 112.11(18).
distance, 3.0428(3) Å), is shorter than twice the van der Waals
radius of palladium (1.63 Å). In the only compounds related to
8a·CH2Cl2, two non-organometallic trifluoroacetato complexes,
the Pd(1)−Pd(2) distances are 3.165 and 3.412 Å, too long for
any bonding or attractive interaction between the two metal
atoms.44 In 9a1 the xylyl group in the iminobenzoyl fragment is
folded toward the chloro ligand, thus avoiding contact with the
H6 proton.
With the exception of 3aBr and 9a1, the complexes display
intermolecular nonclassical C−H···O hydrogen bonds (see
Figures 2, 4, 5, and 7) with the involvement of one OMe group
(3bCl) or the counteranions, and additionally, 3bCl shows
nonclassical C−H···Cl hydrogen bonds. A 3D network results
in the case of 5a3, and layers parallel to the bc plane form in 13.
NMR Spectroscopy. Because of their low solubility in
CDCl3, the NMR spectra of complexes 5a4, 6a1, 6a2 (13C),
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Figure 3. Thermal ellipsoid representation plot (50% probability) of
the cation of complex 5a3 (40%). Hydrogen atoms and the ClO4
anion are omitted for clarity. Selected bond lengths (Å) and angles
(deg): Pd(1)−C(1) 2.015(2), Pd(1)−N(1) 2.0429(17), Pd(1)−N(2)
2.1425(17), Pd(1)−P(1) 2.2716(5), C(2)−C(7) 1.469(3), N(1)−
C(7) 1.285(3), N(1)−O(1) 1.402(2), O(1)−C(9) 1.455(3), C(9)−
C(10) 1.505(3), N(2)−C(10) 1.353(3); C(1)−Pd(1)−N(1)
79.72(8), N(1)−Pd(1)−N(2) 88.47(7), C(1)−Pd(1)−P(1)
93.83(6), N(2)−Pd(1)−P(1) 99.27(5), N(1)−C(7)−C(2)
112.14(18), C(7)−N(1)−O(1) 116.44(16), N(1)−O(1)−C(9)
108.46(15), O(1)−C(9)−C(10) 111.46(17).
Figure 5. Left: Thermal ellipsoid representation plot (50%
probability) of the cation of complex 8a·CH2Cl2. Hydrogen atoms,
the TfO anion, and the solvent are omitted for clarity. Right: Two
oxygens of the triflate anions join the molecules by C−H···O into
layers parallel to the a axis. Selected bond lengths (Å) and angles
(deg): Pd(1)−Pd(2) 3.0428(3), Pd(1)−C(1) 1.9847(18), Pd(1)−
N(1) 1.9882(15), Pd(1)−O(4) 2.0491(13), Pd(1)−N(2) 2.1364(15),
C(2)−C(7) 1.466(2), N(1)−C(7) 1.294(2), O(1)−N(1) 1.4056(18),
O(1)−C(9) 1.446(2), C(9)−C(10) 1.510(3), N(2)−C(10) 1.349(2),
Pd(2)−C(21) 1.9807(18), Pd(2)−N(3) 1.9835(15), Pd(2)−O(3)
2.0533(13), Pd(2)−N(4) 2.1275(15), C(22)−C(27) 1.463(3),
N(3)−C(27) 1.295(2), O(2)−N(3) 1.3987(19), O(2)−C(29)
1.442(2), C(29)−C(30) 1.513(3), N(4)−C(30) 1.348(2); C(1)−
Pd(1)−N(1) 79.93(7), C(1)−Pd(1)−O(4) 94.75(6), N(1)−Pd(1)−
N(2) 92.60(6), O(4)−Pd(1)−N(2) 91.92(6), C(1)−Pd(1)−Pd(2)
87.82(5), C(21)−Pd(2)−N(3) 80.39(7), C(21)−Pd(2)−O(3)
94.95(7), N(3)−Pd(2)−N(4) 92.81(6), O(3)−Pd(2)−N(4)
91.37(6).
1
and 6a4 were measured in CD3CN. The H and 13C methyl
nuclei of the SMe group in complex 6a3 (2.01 and 15.8 ppm,
respectively) are shielded with respect to those in 4 and in the
remaining complexes 6 (2.50−2.68 and 16.4−16.9 ppm,
respectively). This is probably caused by the aryl groups of
the phosphine ligand. The singlet observed at room temper-
ature for the methylene protons (H9, Chart 1; 4.58−5.46 ppm)
changes to an AB system when the temperature is lowered. The
methoxy aryl substituents in complexes 3bCl and 3bBr must be
responsible for the shielding of the C1 and C2 resonances with
respect to those in the “a” derivatives bearing the unsubstituted
arene (Δδ ≈ 20 and 5 ppm, respectively), as found previously
when comparing the spectra of 1a and 1b.13
In the iminobenzoyl complexes 9−11, the isocyanide
insertion into the Pd−Caryl bond produces a marked shielding
of the C resonances in the resulting six-membered palladacycle,
with respect to their precursor complexes (Δδ (ppm) = 20−22
(C1), 9−16 (C2), and 10−17 (C7)). At room or lower
temperature, the CNXy methyl groups give two separate
resonances in 9a1, while at 55 °C only one resonance is
observed. However, only below −30 °C do the spectra of
complexes 10a1 and 11a1 show two Me(Xy) resonances,
Figure 4. Left: Thermal ellipsoid representation plot (50%
probability) of the cation of complex 6a1. The ClO4 anion is omitted
for clarity. Right: The molecules are arranged into ribbons parallel to
(1 0 −1) by C−H···O(ClO4) interactions. Selected bond lengths (Å)
and angles (deg): Pd(1)−C(11) 1.9391(19), Pd(1)−N(1)
1.9960(15), Pd(1)−C(1) 2.0127(18), Pd(1)−S(1) 2.4072(5),
C(2)−C(7) 1.473(2), N(1)−C(7) 1.288(2), N(1)−O(1)
1.4116(19), O(1)−C(9) 1.420(2), S(1)−C(9) 1.8227(19); C(11)−
Pd(1)−C(1) 96.99(8), N(1)−Pd(1)−C(1) 80.05(7), C(11)−Pd(1)−
S(1) 99.48(5), N(1)−Pd(1)−S(1) 83.45(5), N(1)−C(7)−C(2)
110.90(16), C(7)−N(1)−O(1) 117.02(15), N(1)−O(1)−C(9)
109.72(13), O(1)−C(9)−S(1) 114.39(12).
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Chart 1. Atom Numbering Used in the NMR Assignments
Figure 6. Thermal ellipsoid representation plot (50% probability) of
complex 9a1. Hydrogen atoms are omitted for clarity. Selected bond
lengths (Å) and angles (deg): Pd(1)−C(15) 1.9617(19), Pd(1)−N(1)
2.0491(15), Pd(1)−N(2) 2.1738(15), Pd(1)−Cl(1) 2.3037(5),
C(15)−N(3) 1.261(2), C(2)−C(7) 1.484(3), N(1)−C(7) 1.288(2),
N(1)−O(1) 1.4156(19), O(1)−C(9) 1.442(2), C(9)−C(10)
1.507(3), N(2)−C(10) 1.349(2); C(15)−Pd(1)−N(1) 86.03(7),
N(1)−Pd(1)−N(2) 86.78(6), C(15)−Pd(1)−Cl(1) 91.93(5),
N(2)−Pd(1)−Cl(1) 95.01(4), C(1)−C(15)−Pd(1) 107.93(12),
N(1)−C(7)−C(2) 116.85(16), C(7)−N(1)−O(1) 112.38(15),
N(1)−O(1)−C(9) 111.67(13), O(1)−C(9)−C(10) 112.73(15).
which at −60 °C is slow on the NMR time scale, showing two
resonances at 1.59 and 1.61 ppm. In the case of complex 12,
whatever the coordination mode of the Bubpy ligand, the
t
NMR is indicative of a fluxional process interchanging the
1
relative position of the two halves of the ligand. While the H
suggesting that the isocyanide ligand exerts less congestion at
NMR spectra of the isocyanide complexes 14 and 15 show the
CO2Me protons very close together at around 3.75 ppm or
accidentally coinciding, respectively, in those of their
homologues with nitrogen donor ligands, 12 and 13, one of
such resonances remains unaltered, while the other one is
appreciably shielded (Δ = 0.35 ppm), which could be attributed
the iminoacyl Xy group than the chloro ligand in complex 9a1.
1
The room-temperature H NMR spectra of 11a2 and 12
show only one resonance of 18 H for both tert-buthyl groups at
1.57 and 1.37 ppm, respectively. In 11a2, this suggests an
interchange between the coordinated and inserted isocyanides,
Figure 7. Left: Thermal ellipsoid representation plot (50% probability) of complex 13. Right: Layers parallel to the bc plane resulting from
intermolecular C−H···O hydrogen bonds. Selected bond lengths (Å) and angles (deg): Pd(1)−C(1) 2.0485(18), Pd(1)−N(1) 1.9390(14), Pd(1)−
C(10) 2.0623(17), Pd(1)−N(2) 2.0489(14), C(9)−C(10) 1.332(2), C(9)−O(1) 1.418(2), N(1)−O(1) 1.4044(18), C(7)−N(1) 1.296(2), C(2)−
C(7) 1.478(2), C(1)−C(2) 1.423(3); N(1)−Pd(1)−C(1) 80.18(7), C(1)−Pd(1)−N(2) 102.62(6), N(1)−Pd(1)−C(10) 79.70(6), N(2)−Pd(1)−
C(10) 97.55(6), N(1)−O(1)−C(9) 108.32(12), C(10)−C(9)−O(1) 121.65(15), C(9)−C(10)−Pd(1) 110.84(12), C(7)−N(1)−Pd(1)
122.27(12), N(1)−C(7)−C(2) 110.82(15), C(1)−C(2)−C(7) 116.17(15), C(2)−C(1)−Pd(1) 110.31(12).
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t
3bBr, 250 mg, 2.43 mmol) in acetone (for 3aBr, 35; for 3bBr, 15 mL)
overnight. The solvent was removed under vacuum, CH2Cl2 (20 mL)
was added, and the suspension was filtered through a short pad of
Celite. The solution was concentrated under vacuum (2 mL), Et2O
(15 mL) was added, and the suspension was filtered. The solid was
washed with Et2O (3 × 3 mL) and dried by suction to give a pale
yellow solid. 3aBr was additionally recrystallized from CH2Cl2/Et2O
and dried, first by suction and then in a vacuum oven (70 °C, 5 h).
3aCl: Yield: 413 mg, 1.13 mmol, 90%. Mp: 245 °C. 1H NMR (400
MHz, CDCl3, 25 °C): δ 2.35 (s, 3 H, Me), 5.18 (s, 2 H, CH2), 7.07
(td, 1 H, H4, 3JHH = 7 Hz, 4JHH = 1 Hz), 7.11 (td, 1 H, H5, 3JHH = 7 Hz,
4JHH = 2 Hz), 7.18 (dd, 1 H, H3, 3JHH = 7 Hz, 4JHH = 2 Hz), 7.42 (d, 1
H, H11, 3JHH = 8 Hz), 7.46 (ddd, 2 H, H13, 3JHH = 8 Hz, 3JHH = 5 Hz,
4JHH = 1 Hz), 7.88 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 2 Hz), 8.01 (dd,
to the anisotropic effect of the aromatic rings of the Bubpy or
ClCH2py-2 ligands coordinated in cis position with respect to
one of the C(CO2Me) fragments.
CONCLUSION
■
We report a chelate-to-pincer complex conversion process
using a new strategy, which consists in the generation of a
coordinating side arm in the chelating ligand by attacking it
with a ligand. Both the chelating and the added ligands must
remain bonded in such a manner as to permit the coordination
of a donor atom of the added ligand. The chosen processes to
illustrate this method have been (1) the reaction between a
cyclopalladated oxime complex and a halomethylene derivative
XCH2E (X = Cl, Br, E = py-2, SMe) and a base and (2) the
reaction between DMAD and an oximato complex. Some of the
resulting oxime ether pincer complexes insert isocyanides in the
Pd−C bond.
4
3
1 H, H6, 3JHH = 7 Hz, JHH = 1 Hz), 9.45 (d, 1 H, H14, JHH = 5 Hz);
(400 MHz, CDCl3, −60 °C): δ 2.42 (s, 3 H, Me), 5.24 (AB system, 2
H, CH2, νA = 5.21, νB = 5.27, JAB = 13 Hz), 7.17 (t, 1 H, H4, 3JHH = 7
3
3
Hz), 7.14 (t, 1 H, H5, JHH = 7 Hz), 7.27 (d, 1 H, H3, JHH = 7 Hz),
7.53−7.57 (m, 2 H, H11+13), 7.98−8.01 (m, 2 H, H6+12), 9.38 (d, 1 H,
H14, JHH = 5 Hz). 13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ 11.8
3
(Me8), 76.4 (C9), 124.7 (C4), 125.1 (C11+13), 126.1 (C3), 129.6 (C5),
136.1 (C6), 139.1 (C12), 141.3 (C2), 151.8 (C10), 152.3 (C14), 154.3
(C1), 171.1 (C7). Anal. Calcd for C14H13ClN2OPd: C, 45.80; H, 3.57;
N, 7.63. Found: C, 45.58; H, 3.54; N, 7.58.
EXPERIMENTAL SECTION
■
General Procedures. When not stated, the reactions were carried
out without precautions to exclude light or atmospheric oxygen or
moisture. Melting points were determined on a Reichert apparatus and
are uncorrected. Elemental analyses were carried out with a Carlo Erba
1106 microanalyzer. IR spectra were recorded on a Perkin-Elmer
Spectrum 100 spectrophotometer using Nujol mulls between
polyethylene sheets. NMR spectra were recorded in Bruker Avance,
200, 300, or 400 MHz, NMR spectrometers. The NMR assignments
were performed with the help of APT, HMQC, and HMBC
experiments. The atom numbering used in NMR assignments is
shown in Chart 1. High-resolution ESI mass spectra were recorded on
an Agilent 6220 Accurate Mass TOF LC/MS spectrometer.
3aBr: Yield: 275 mg, 0.67 mmol, 62%. Mp: 220 °C. 1H NMR (300
MHz, CDCl3, 25 °C): δ 2.35 (s, 3 H, Me), 5.19 (s, 2 H, CH2), 7.02−
7.10 (m, 2 H), 7.16−7.22 (m, 1 H, H3 or 5), 7.42−7.46 (m, 2 H,
H
11+13), 7.89 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 2 Hz), 8.24−8.30 (m,
1 H, H4 or 6), 9.56−9.58 (m, 1 H, H14); (400 MHz, CDCl3, −60 °C): δ
2.43 (s, 3 H, Me), 5.26 (AB system, 2 H, CH2, νA = 5.22, νB = 5.30, JAB
= 14 Hz), 7.10−7.16 (m, 2 H), 7.27−7.29 (m, 1 H, H3 or 5), 7.51−7.56
(m, 2 H, H11+13), 8.00 (“t”, 1 H, H12, 3JHH = 8 Hz), 8.23−8.27 (m, 1 H,
3
H
4 or 6), 9.51 (“d”, 1 H, H14, JHH = 5 Hz). 13C{1H} NMR (75 MHz,
t
CDCl3, 25 °C): δ 11.9 (Me8), 76.6 (C9), 124.6 (CH, Ar), 125.1 (C13),
125.2 (C11), 126.2 (C3 or 5), 129.9 (CH, Ar), 139.0 (C4 or 6), 139.1
(C12), 141.6 (C2), 152.0 (C10), 153.6 (C1), 153.9 (C14), 170.9 (C7).
Anal. Calcd for C14H13BrN2OPd: C, 40.86; H, 3.18; N, 6.81. Found:
C, 40.71; H, 3.17; N, 6.78. Crystals suitable for an X-ray diffraction
study were grown by slow diffusion of Et2O into a solution of 3aBr in
CH2Cl2.
ClCH2SMe, PTol3, BuNC, XyNC, AgTfO (Fluka), (ClCH2pyH-2)
Cl (Lancaster), (BrCH2pyH-2)Br, Bubpy, KtBuO, AgClO4, AgAcO
t
(Aldrich), NaAcO (Sigma), MeCN (Carlo Erba), and dimethyl
acetylenedicarboxylate (DMAD, Alfa Aesar) were obtained from
commercial sources. The syntheses of complexes 1a, 1b, and 2a were
recently reported by us.13
X-ray Crystallography. Compounds 3aBr, 3bCl, 5a3, 6a1,
8a1·CH2Cl2, 9a1, and 13 were measured on a Bruker Smart APEX
machine at 100 K. Data were collected using monochromated Mo Kα
radiation in ω scan mode. The structures were solved by direct
methods. All were refined anisotropically on F2. The methyl groups
were refined using rigid groups (AFIX 137), and the other hydrogens
were refined using a riding model. Further details on crystal data, data
collection, and refinements are summarized in the Supporting
Information.
1
3bCl: Yield: 130 mg, 0.284 mmol, 71%. Mp: 187 °C (dec). H
NMR (400 MHz, CDCl3, 25 °C): δ 2.32 (s, 3 H, Me), 3.84 (s, 3 H,
OMe), 3.92 (s, 3 H, OMe), 3.94 (s, 3 H, OMe), 5.18 (s, 2 H, CH2),
6.69 (s, 1 H, H3), 7.39 (d, 1 H, H11, 3JHH = 8 Hz), 7.49 (ddd, 1 H, H13,
3
4
3
3JHH = 8 Hz, JHH = 6 Hz, JHH = 1 Hz), 7.88 (td, 1 H, H12, JHH = 8
Hz, 4JHH = 2 Hz), 9.82 (dd, 1 H, H14, 3JHH = 6 Hz, 4JHH = 2 Hz); (400
MHz, CDCl3, −60 °C): δ 2.41 (s, 3 H, Me), 3.90 (s, 3 H, OMe), 3.93
(s, 3 H, OMe), 4.00 (s, 3 H, OMe), 5.25 (AB system, 2 H, CH2, νA =
5.20, νB = 5.30, JAB = 13 Hz), 6.74 (s, 1 H, H3), 7.51 (d, 1 H, H11, 3JHH
Synthesis of [Pd{C,N,N′-ArR{C(Me)NOCH2(C5H4N)-2}-2}X]
(ArR = C6H4, X = Cl (3aCl), Br (3aBr); ArR = C6H(OMe)3-4,5,6, X
= Cl (3bCl), Br (3bBr)). To a suspension containing KtBuO (for 3aCl,
298 mg, 2.52 mmol; for 3aBr, 263 mg, 2.23 mmol; for 3bCl, 98 mg,
0.83 mmol; for 3aBr, 88 mg, 0.75 mmol) and (XCH2pyH-2)X (for
3aCl, X = Cl, 206 mg, 1.26 mmol; for 3aBr, X = Br, 281 mg, 1.10
mmol; for 3bCl, X = Cl, 67 mg, 0.41 mmol; for 3bBr, X = Br, 281 mg,
1.10 mmol) in CH2Cl2 (for 3aCl, 3aBr, 20; for 3bCl, 3bBr, 10 mL)
was added complex 1a (for 3aCl, 346 mg, 0.63 mmol; for 3aBr, 299
mg, 0.54 mmol) or 1b (for 3bCl, 146 mg, 0.20 mmol; for 3bBr, 135
mg, 0.18 mmol). The resulting suspension was stirred for 2.5 (3bCl,
3bBr), 3 (3aCl), or 4.5 (3aBr) h and filtered through a short pad of
Celite, the solution was concentrated under vacuum to 1 (3aCl, 3bCl)
or 2 mL (3aBr, 3bBr), and Et2O (15 mL) was added. For 3aCl and
3bCl the suspension was filtered and the solid was washed with Et2O
(3 × 2 mL) and dried, first by suction and then in a vacuum oven (70
°C, 15 (3aCl) or 5 h (3bCl), to give pale tan colored solids. A second
crop of 3aCl was obtained by concentrating the mother liquor almost
to dryness, stirring the residue with Et2O (15 mL), filtering the
suspension, washing the solid with Et2O (3 × 2 mL), and drying it as
above. For 3aBr and 3bBr,41 the suspension was filtered, and the solid
collected was reacted with NaBr (for 3aBr, 450 mg, 4.37 mmol; for
= 8 Hz), 7.58 (t, 1 H, H13, JHH = 8 Hz), 7.99 (t, 1 H, H12, JHH = 8
3
3
Hz), 9.59 (d, 1 H, H14, JHH = 8 Hz). 13C{1H} NMR (75 MHz,
3
CDCl3, 25 °C): δ 12.4 (Me8), 56.3 (OMe), 60.9 (OMe), 62.0 (OMe),
76.2 (C9), 107.3 (C3), 124.7 (C11), 124.9 (C13, 136.8 (C1 or 2), 136.9
(C1 or 2), 139.0 (C12), 144.9 (C, Ar), 151.25 (C, Ar, or C10), 151.29
(C, Ar or C10), 151.8 (C14), 159.5 (C, Ar), 170.9 (C7). Anal. Calcd for
C17H19ClN2O4Pd: C, 44.66; H, 4.19; N, 6.13. Found: C, 44.28; H,
4.11; N, 5.95. Crystals suitable for an X-ray diffraction study were
grown by slow diffusion of Et2O into a solution of 3bCl in CH2Cl2.
3bBr: Yield: 103 mg, 0.21 mmol, 56%. Mp: 197 °C (dec). 1H NMR
(400 MHz, CDCl3, 25 °C): δ 2.32 (s, 3 H, Me), 3.84 (s, 3 H, OMe),
3.91 (s, 3 H, OMe), 3.92 (s, 3 H, OMe), 5.20 (s, 2 H, CH2), 6.69 (s, 1
H, H3), 7.39 (d, 1 H, H11, 3JHH = 8 Hz), 7.47 (ddd, 1 H, H13, 3JHH = 8
Hz, 3JHH = 6 Hz, 4JHH = 1 Hz), 7.88 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH
=
3
4
5
2 Hz), 9.82 (ddd, 1 H, H14, JHH = 6 Hz, JHH = 2 Hz, JHH = 1 Hz);
(400 MHz, CDCl3, −55 °C): δ 2.41 (s, 3 H, Me), 3.90 (s, 3 H, OMe),
3.92 (s, 3 H, OMe), 3.97 (s, 3 H, OMe), 5.28 (AB system, 2 H, CH2,
νA = 5.20, νB = 5.35, JAB = 14 Hz), 6.75 (s, 1 H, H3), 7.51 (d, 1 H, H11,
3
3
3JHH = 8 Hz), 7.55 (“t”, 1 H, H13, JHH ≈ JHH ≈ 7 Hz), 7.99 (t, 1 H,
3
3
H12, JHH = 8 Hz), 9.71 (d, 1 H, H14, JHH = 6 Hz). 13C{1H} (NMR
7440
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Organometallics
Article
(75 MHz, CDCl3, 25 °C): δ 12.5 (Me8), 56.4 (OMe), 60.9 (OMe),
62.1 (OMe), 76.5 (C9), 107.4 (C3), 124.8 (C11 or 13), 125.1 (C11 or 13),
136.7 (C1), 137.1 (C2), 139.0 (C12), 144.5 (C, Ar), 151.4 (C, Ar),
151.6 (C10), 153.5 (C14), 159.2 (C, Ar), 170.7 (C7). Anal. Calcd for
C17H19BrN2O4Pd: C, 40.70; H, 3.82; N, 5.58. Found: C, 40.36; H,
3.87; N, 5.49.
(Ω−1·cm2·mol−1): 129. Anal. Calcd for C19H22ClN3O5Pd: C, 44.38;
H, 4.31; N, 8.17. Found: C, 44.68; H, 4.35; N, 8.25.
5a3·H2O: Yield: 78 mg, 0.104 mmol, 84%. Mp: > 200 °C (dec). 1H
NMR (400 MHz, CDCl3, 25 °C): δ 1.73 (br s, 2 H, H2O), 2.36 (s, 9
H, Me, PTol3), 2.50 (s, 3 H, Me8), 5.47 (s, 2 H, CH2), 6.50 (ddd, 1 H,
H6, 3JHH = 8 Hz, 3JHP = 6 Hz, 4JHH = 1 Hz), 6.63 (td, 1 H, H4 or 5, 3JHH
= 8 Hz, 4JHH = 1 Hz), 6.94 (ddd, 1 H, H13, 3JHH = 8 Hz, 3JHH = 6 Hz,
Synthesis of [Pd{C,N,S-C6H4{C(Me)NOCH2SMe}-2}Cl] (4a).
To a suspension containing KtBuO (46 mg, 0.39 mmol) and complex
1a (107 mg, 0.19 mmol) in CH2Cl2 (8 mL) was added ClCH2SMe
(41 μL, 0.40 mmol). The resulting suspension was stirred for 18 h and
filtered through a short pad of Celite, the solution was concentrated
under vacuum (1 mL), Et2O (15 mL) was added, and the suspension
was filtered. The solid collected was washed with Et2O (3 × 2 mL) and
dried, first by suction and then in a vacuum oven (70 °C, 15 h), to give
4a·0.3H2O as a light brown solid. Yield: 90 mg, 0.26 mmol, 68%. Mp:
3
4
4JHH = 1 Hz), 7.05 (dd, 1 H, H4 or 5, JHH = 8 Hz, JHH = 1 Hz), 7.19
(m, 6 H, meta-CH, PTol3), 7.34 (dd, 1 H, H3, JHH = 8 Hz, JHH = 1
3
4
Hz), 7.53 (m, 6 H, ortho-CH, PTol3), 7.68 (d, 1 H, H14, 3JHH = 6 Hz),
7.73 (d, 1 H, H11, 3JHH = 8 Hz), 7.85 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH
=
1 Hz); (400 MHz, CDCl3, −60 °C): δ 2.28 (br s, 2 H, H2O), 2.40 (br
s, 9 H, Me, PTol3), 2.55 (s, 3 H, Me8), 5.47 (AB system, 2 H, CH2, νA
3
3
= 5.40, νB = 5.55, JAB = 14 Hz), 6.49 (“t”, 1 H, H6, JHP ≈ JHH = 7
Hz), 6.69 (t, 1 H, H4 or 5, 3JHH = 7 Hz), 6.98 (“t”, 1 H, H13, 3JHH ≈ 3JHH
≈ 7 Hz), 7.12 (t, 1 H, H4 or 5, 3JHH = 7 Hz), 7.24 (vbr s, 6 H, meta-CH,
1
196 °C (dec). H NMR (400 MHz, CDCl3, 25 °C): δ 1.57 (s, 0.6 H,
H2O), 2.27 (s, 3 H, Me8), 2.54 (s, 3 H, MeS), 5.10 (s, 2 H, CH2), 7.03
3
PTol3), 7.41 (d, 1 H, H3, JHH = 7 Hz), 7.53−8.04 (vbr s, 6 H, ortho-
3
4
3
(dd, 1 H, H3, JHH = 8 Hz, JHH = 2 Hz), 7.08 (td, 1 H, H4, JHH = 8
CH, PTol3), 7.64 (d, 1 H, H14, 3JHH = 6 Hz), 7.80 (d, 1 H, H11, 3JHH
=
Hz, JHH = 2 Hz), 7.16 (td, 1 H, H5, JHH = 8 Hz, JHH = 2 Hz), 7.76
4
3
4
3
8 Hz), 7.93 (t, 1 H, H12, JHH = 8 Hz). 13C{1H} NMR (75 MHz,
3
4
(dd, 1 H, H6, JHH = 8 Hz, JHH = 2 Hz). 13C{1H} NMR (100 MHz,
solvent, CDCl3, 25 °C): δ 12.4 (Me8), 16.4 (Me10), 78.1 (C9), 125.3
(C4), 126.7 (C3), 130.8 (C5), 134.0 (C6), 144.9 (C2), 155.7 (C1),
170.2 (C7). Anal. Calcd for C10H12.6ClNO1.3PdS: C, 35.17; H, 3.72; N,
4.10; S, 9.39. Found: C, 35.00; H, 3.44; N, 4.21; S, 9.51.
CDCl3, 25 °C): δ 12.4 (Me8), 21.4 (Me, PTol3), 77.3 (C9), 124.9
1
(C13), 125.3 (d, ipso-C, PTol3, JCP = 53 Hz), 125.7 (C4 or 5), 126.9
3
(C11), 127.6 (C3), 129.88 (d, meta-CH, PTol3, JCP = 12 Hz), 129.90
(C4 or 5), 134.8 (d, ortho-CH, PTol3, 2JCP = 13 Hz), 138.3 (d, C6, 3JCP
=
11 Hz), 140.2 (C12), 142.6 (d, para-C, PTol3, 4JCP = 2 Hz), 142.8 (C2),
3
152.2 (d, C14, JCP = 3 Hz), 152.56 (C1 or 10), 152.61 (C1 or 10), 171.7
Synthesis of [Pd{C,N,N′-C6H4{C(Me)NOCH2(C5H4N-2)}-2}L]-
ClO4 (L = XyNC (5a1), tBuNC (5a2), PTol3 (5a3), MeCN (5a4)). A
mixture containing AgClO4 (for 5a1, 70 mg, 0.33 mmol; for 5a2, 181
mg, 0.85 mmol; for 5a4, 78 mg, 0.37 mmol) or NaClO4·H2O (for 5a3,
25 mg, 0.18 mmol), complex 3aCl (for 5a1, 114 mg, 0.31 mmol; for
5a2, 307 mg, 0.84 mmol; for 5a3, 51 mg, 0.12 mmol; for 5a4, 134 mg,
0.37 mmol), and the appropriate ligand (for 5a1, XyNC, 41 mg, 0.31
mmol; for 5a2, tBuNC, 97 μL, 0.86 mmol; for 5a3, PTol3, 38 mg, 0.13
mmol; for 5a4, MeCN, 3 mL, 57.3 mmol) in acetone (for 5a1 and
5a2, 20 mL; for 5a3, 10 mL) or in CH2Cl2 (for 5a4, 5 mL) was stirred
for 40 min (5a4), 2 h (5a1, 5a3), or 4 h (5a2) protected from light
and then filtered through a short pad of Celite. The solution was
concentrated under vacuum (2 mL), Et2O (20 mL) was added, and
the suspension was filtered. The solid collected was washed with Et2O
(3 × 2 mL) and dried, first by suction and then in a vacuum oven at 75
°C for 5 h, to give the title compound as an off-white solid.
(C7). 31P{1H} NMR (122 MHz, CDCl3, 25 °C): δ 40.45. IR (cm−1):
ν(ClO) 1093, δ(OClO) 622. ΛM (Ω−1·cm2·mol−1): 124. Anal. Calcd
for C35H36ClN2O6PPd: C, 56.19; H, 4.82; N, 3.72. Found: C, 55.97;
H, 4.99; N, 3.82. HRMS (ESI+, m/z): calcd for C35H34N2OPPd [M]+
636.1468, found 636.1474, error = 0.94 ppm. Crystals suitable for an
X-ray diffraction study were grown by slow diffusion of Et2O into a
solution of 5a3 in CH2Cl2.
5a4: Yield: 153 mg, 0.324 mmol, 89%. Mp: 180 °C (dec). 1H NMR
(300 MHz, CD3CN, 25 °C): δ 1.97 (s, 3 H, MeCN), 2.42 (s, 3 H,
Me8), 5.23 (s, 2 H, CH2), 7.21 (td, 1 H, H5, 3JHH = 7 Hz, 4JHH = 2 Hz),
7.25 (td, 1 H, H4, 3JHH = 7 Hz, 4JHH = 1 Hz), 7.37 (dd, 1 H, H6, 3JHH
=
7 Hz, 4JHH = 1 Hz), 7.41 (dd, 1 H, H3, 3JHH = 7 Hz, 4JHH = 2 Hz), 7.65
(ddd, 1 H, H13, 3JHH = 8 Hz, 3JHH = 5 Hz, 4JHH = 1 Hz), 7.69 (d, 1 H,
H11, 3JHH = 8 Hz), 8.13 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 1 Hz), 8.71
(d, 1 H, H14, 3JHH = 5 Hz). 13C{1H} NMR (75 MHz, CD3CN, 25 °C):
δ. 1.8 (Me, CH3CN), 12.6 (Me8), 77.2 (C9), 118.3 (CH3CN), 126.9
(C13), 127.1 (C4), 127.4 (C11), 128.8 (C3), 131.4 (C5), 134.9 (C6),
141.9 (C12), 142.3 (C2), 152.6 (C14), 152.9 (C10), 154.4 (C1), 177.1
(C7). IR (cm−1): ν(CN) 2326, ν(ClO) 1093, δ(OClO) 624. ΛM
(Ω−1·cm2·mol−1): 130. Anal. Calcd for C16H16ClN3O5Pd: C, 40.70; H,
3.42; N, 8.90. Found: C, 40.74; H, 3.44; N, 8.82.
1
5a1: Yield: 134 mg, 0.24 mmol, 77%. Mp: 243 °C (dec). H NMR
(400 MHz, CD2Cl2, 25 °C): δ 2.54 (s, 3 H, Me8), 2.58 (s, 6 H, Me,
Xy), 5.32 (s, 2 H, CH2), 7.17 (td, 1 H, H5, 3JHH = 8 Hz, 4JHH = 2 Hz),
7.28 (td, 1 H, H4, 3JHH = 8 Hz, 4JHH = 2 Hz), 7.30 (m, 2 H, meta-CH,
Xy), 7.43 (dd, 1 H, para-CH, Xy, 3JHH = 8 Hz, 3JHH = 7 Hz), 7.46 (dd,
3
4
3
1 H, H6, JHH = 8 Hz, JHH = 2 Hz), 7.45 (dd, 1 H, H3, JHH = 8 Hz,
4JHH = 2 Hz), 7.66 (ddd, 1 H, H13, 3JHH = 8 Hz, 3JHH = 5 Hz, 4JHH = 2
Hz), 7.76 (ddd, 1 H, H11, 3JHH = 8 Hz, 4JHH = 2 Hz, 5JHH = 1 Hz), 8.18
(td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 2 Hz), 8.76 (ddd, 1 H, H14, 3JHH = 5
Hz, 4JHH = 2 Hz, 5JHH = 1 Hz).13C{1H} NMR (100 MHz, CD2Cl2, 25
°C): δ 12.5 (Me8), 19.2 (Me, Xy), 77.2 (C9), 125.6 (m, ipso-C, Xy),
126.8 (C13), 126.9 (C4), 127.8 (C11), 128.96 (C3), 129.02 (meta-C,
Xy), 131.6 (para-C, Xy), 131.8 (C5), 136.6 (ortho-C, Xy), 137.9 (C6),
Synthesis of [Pd{C,N,S-C6H4{C(Me)NOCH2SMe}-2}L]ClO4 (L
t
= XyNC (6a1), BuNC (6a2), PTol3 (6a3), MeCN (6a4)). Complex
4a (for 6a1, 102 mg, 0.30 mmol; for 6a2, 101 mg, 0.30 mmol; for 6a3,
99 mg, 0.30 mmol; for 6a4, 95 mg, 0.28 mmol) was added to a
solution containing AgClO4 (97%, for 6a1, 66 mg, 0.31 mmol; for 6a2
and 6a3, 65 mg, 0.30 mmol; for 6a4, 61 mg, 0.29 mmol) and the
appropriate ligand (for 6a1, XyNC, 40 mg, 0.31 mmol; for 6a2,
tBuNC, 35 μL, 0.31 mmol; for 6a3, PTol3, 90 mg, 0.30 mmol; for 6a4,
MeCN, 2 mL, 38.2 mmol) in acetone (for 6a1 and 6a2, 10 mL; for
6a3, 20 mL; for 6a4, 8 mL). The resulting suspension was stirred
protected from light for 0.5 (6a3), 1.5 (6a1, 10a4), or 3 h (6a2). For
6a1 and 6a2 the suspension was filtered through a short pad of Celite
and concentrated under vacuum (2 mL), Et2O (15 mL) was added,
and the suspension was filtered. The solid collected was washed with
Et2O (3 × 3 mL) and dried by suction to give a pale orange (6a1) or
yellow (6a2) solid. For 6a3 and 6a4 the reaction mixture was
concentrated to dryness, CH2Cl2 (10 mL) was added, and the
suspension was filtered through a short pad of Celite. The solution was
concentrated (1 mL), Et2O (15 mL) was added, and the suspension
was stirred (for 6a3, 30 min in an ice/water bath) and filtered. The
solid collected was washed wit Et2O (3 × 2 mL), and 6a3 was
additionally recrystallized from CH2Cl2/Et2O and dried, first by
suction and then in a vacuum oven (6a3: 80 °C, 5 h; 6a4: 65 °C, 15
h), to give 6a3·H2O or 6a4 as pale tan solids.
141.8 (C2),142.0 (C12), 143.5 (1:1:1, t, CN, JCN = 22 Hz), 152.6
1
(C10), 153.2 (C1), 153.9 (C14), 175.8 (C7). IR (cm−1): ν(CN)
2185, ν(ClO) 1090, δ(OClO) 622. ΛM (Ω−1·cm2·mol−1): 134. Anal.
Calcd for C23H22ClN3O5Pd: C, 49.13; H, 3.94; N, 7.47. Found: C,
49.01; H, 3.90; N, 7.53.
1
5a2: Yield: 354 mg, 0.69 mmol, 82%. Mp: 154 °C. H NMR (400
MHz, CD2Cl2, 25 °C): δ 1.75 (s, 9 H, tBu), 2.47 (s, 3 H, Me8), 5.24 (s,
2 H, CH2), 7.20 (td, 1 H, H5, 3JHH = 7 Hz, 4JHH = 1 Hz), 7.26 (td, 1 H,
H4, 3JHH = 7 Hz, 4JHH = 1 Hz), 7.32 (dd, 1 H, H6, 3JHH = 7 Hz, 4JHH
=
1 Hz), 7.41 (dd, 1 H, H3, 3JHH = 7 Hz, 4JHH = 1 Hz), 7.71−7.75 (m, 2
H, H11+13), 8.15 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 2 Hz), 8.62 (ddd, 1
H, H14, JHH = 5 Hz, JHH = 2 Hz, JHH = 1 Hz). 13C{1H} NMR (75
3
4
4
MHz, CD2Cl2, 25 °C): δ 12.4 (Me8), 30.1 (Me, Bu), 60.7 (CMe3),
t
77.1 (C9), 126.7 (C4), 127.0 (C13), 127.6 (C11), 128.7 (C3), 130.5
(1:1:1, t, CN, JCN = 19 Hz), 131.7 (C5), 137.5 (C6), 141.7 (C12),
1
141.9 (C2), 152.4 (C10), 152.8 (C1), 153.8 (C14), 175.3 (C7). IR
(cm−1): ν(CN) 2223, ν(ClO) 1091, δ(OClO) 623. ΛM
7441
dx.doi.org/10.1021/om3007213 | Organometallics 2012, 31, 7434−7446

Organometallics
Article
1
6a1: Yield: 144 mg, 0.27 mmol, 89%. Mp: 132 °C (dec). H NMR
(400 MHz, CD3CN, 25 °C): δ 2.48 (s, 3 H, Me8), 2.52 (s, 6 H, Me,
Xy), 2.61 (s, 3 H, Me10), 5.28 (br s, 2 H, CH2), 7.27 (td, 1 H, H5, 3JHH
= 8 Hz, 4JHH = 2 Hz), 7.31 (m, 2 H, meta-CH, Xy), 7.32 (td, 1 H, H4,
125.7 (C3 or 6), 129.7 (C4 or 5), 133.1 (C3 or 6), 139.0 (C12), 141.2 (C2),
150.7 (C14), 151.9 (C10), 154.3 (C1), 171.3 (C7), 177.7 (CO2). IR
(cm−1): νasym(CO2) 1622. ΛM (Ω−1·cm2·mol−1): 130. Anal. Calcd for
C16H16.6N2O2.3Pd: C, 48.52; H, 4.48; N, 7.07. Found: C, 48.23; H,
4.21; N, 7.22.
3JHH = 8 Hz, JHH = 2 Hz), 7.43 (t, 1 H, para-CH, Xy, JHH = 8 Hz),
4
3
7.46 (dd, 1 H, H3, 3JHH = 8 Hz, 4JHH = 2 Hz), 7.49 (dd, 1 H, H6, 3JHH
=
Synthesis of [{Pd{C,N,N′-C6H4{C(Me)NOCH2(C5H4N-2)}-
2}}2(μ-OAc)]TfO (8a). To a suspension of AgTfO (99%; 44 mg,
0.17 mmol) and AgAcO (99%; 28 mg, 0.17 mmol) in CH2Cl2 (10
mL) was added complex 3aCl (122 mg, 0.33 mmol). The suspension
was stirred for 45 min protected from light and then filtered through a
short pad of Celite. The solution was concentrated under vacuum (2
mL), Et2O (10 mL) was added, and the suspension was filtered. The
solid collected was washed with Et2O (3 × 4 mL) and dried, first by
suction and then in a vacuum oven (75 °C, 5h), to give 8a as a pale
8 Hz, 4JHH = 2 Hz). 13C{1H} NMR (75 MHz, CD3CN, 25 °C): δ 13.3
(Me8), 16.8 (Me10), 19.0 (Me, Xy), 79.7 (C9), 126.6 (m, ipso-C, Xy),
127.8 (C4), 129.4 (meta-C, Xy), 130.4 (C3), 132.0 (para-C, Xy), 133.4
(C5), 137.2 (ortho-C, Xy), 137.9 (C6), 142.6 (m, CN), 147.1 (C2),
156.6 (C1), 176.3 (C7). IR (cm−1): ν(CN) 2184, ν(ClO) 1097,
δ(OClO) 623. ΛM (Ω−1·cm2·mol−1): 132. Anal. Calcd for
C19H21ClN2O5PdS: C, 42.95; H, 3.98; N, 5.27; S, 6.04. Found: C,
43.08; H, 4.00; N, 5.27; S, 5.95. Crystals suitable for an X-ray
diffraction study were grown by slow evaporation of a solution of 6a1
in acetone.
1
yellow solid. Yield: 133 mg, 0.15 mmol, 92%. Mp: 184 °C (dec). H
NMR (400 MHz, CDCl3, 25 °C): δ 2.44 (s, 3 H, Me8), 2.44 (s, 3 H,
Me, AcO), 4.58 (s, 2 H, CH2), 6.28 (t, 1 H, H5, 3JHH = 7 Hz), 6.35 (d,
1 H, H6, 3JHH = 7 Hz), 6.74 (t, 1 H, H4, 3JHH = 7 Hz), 7.12 (dd, 1 H,
1
6a2: Yield: 136 mg, 0.29 mmol, 94%. Mp: 142 °C (dec). H NMR
(300 MHz, CDCl3, 25 °C): δ 1.71 (s, 9 H, Bu), 2.48 (s, 3 H, Me8),
t
3
4
3
H3, JHH = 7 Hz, JHH = 1 Hz), 7.21 (d, 1 H, H11, JHH = 8 Hz), 7.42
(m, 1 H, H13), 7.79 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 1 Hz), 8.49 (d, 1
H, H14, 3JHH = 5 Hz). 13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ 12.4
(Me8), 25.6 (Me, OAc), 75.6 (C9), 121.1 (q, CF3, JCF = 321 Hz),
124.7 (C13), 125.1 (C4), 125.7 (C11), 126.6 (C3), 128.6 (C5), 133.0
(C6), 139.4 (C12), 140.6 (C2), 148.7 (C14), 151.9 (C10), 154.0 (C1),
173.2 (C7), 183.0 (CO2). 19F{1H} NMR (188 MHz, CDCl3, 25 °C): δ
−78.8 (TfO). IR (cm−1): νasym(CO2) 1551, ν(SO, TfO) 1029. ΛM
(Ω−1·cm2·mol−1): 127. Anal. Calcd for C31H29F3N4O7Pd2S: C, 42.73;
H, 3.35; N, 6.43; S, 3.68. Found: C, 42.40; H, 3.06; N, 6.65; S, 3.20.
Crystals suitable for an X-ray diffraction study were grown by slow
difussion of Et2O into a solution of 8a in CH2Cl2.
2.68 (s, 3 H, Me10), 5.28 (vbr s, 2 H, CH2), 7.17−7.31 (m, 4 H, Ar).
13C{1H} NMR (75 MHz, CD3CN, 25 °C): δ 12.9 (Me8), 16.9 (Me10),
30.0 (Me, Bu), 60.0 (C(Me)3), 79.0 (C9), 126.8 (C, Ar), 128.9 (C,
t
Ar), 132.5 (C, Ar), 135.8 (C, Ar), 145.6 (C2), 155.3 (C1), 174.5 (C7).
IR (cm−1): ν(CN) 2216, ν(ClO) 1091, δ(OClO) 623. ΛM
(Ω−1·cm2·mol−1): 140. Anal. Calcd for C15H21ClN2O5PdS: C, 37.28;
H, 4.38; N, 5.80; S, 6.64. Found: C, 37.36; H, 4.54; N, 5.69; S, 6.41.
1
6a3·H2O: Yield: 142 mg, 0.20 mmol, 67%. Mp: 187 °C (dec). H
NMR (300 MHz, CDCl3, 25 °C): δ 1.63 (br s, 2 H, H2O), 2.01 (s, 3
H, MeS), 2.41 (s, 9 H, Me, PTol3), 2.50 (s, 3 H, Me8), 5.27 (br s, 2 H,
CH2), 6.42 (ddd, 1 H, H6, 3JHH = 8 Hz, 3JHP = 5 Hz, 4JHH = 1 Hz), 6.73
(td, 1 H, H5, 3JHH = 8 Hz, 4JHH = 1 Hz), 7.09 (t, 1 H, H4, 3JHH = 8 Hz),
7.29−7.26 (m, 7 H, H6 + meta-CH, PTol3), 7.52 (m, 6 H, ortho-CH,
PTol3). 13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ 12.7 (Me8), 15.8
(Me10), 21.4 (Me, PTol3), 78.7 (d, C9, 3JCP = 3 Hz), 125.9 (d, ipso-C,
PTol3, 1JCP = 55 Hz), 126.1 (C4), 128.4 (C3), 129.9 (d, meta-C, PTol3,
Synthesis of [Pd{C,N,N′-C(NR)C6H4{C(Me)NOCH2(C5H4N-
t
2)}-2}Cl] (R = Xy (9a1), Bu (9a2)). To a solution of 3aCl (for 9a1,
63 mg, 0.17 mmol; for 9a2, 123 mg, 0.34 mmol) in CH2Cl2 (9a1, 7
mL) or CHCl3 (9a2, 7 mL) was added the appropriate isocyanide (for
t
9a1, XyNC, 31 mg, 0.24 mmol; for 9a2, BuNC, 65 μL, 0.58 mmol).
3JCP = 12 Hz), 131.3 (C5), 134.2 (d, ortho-C, PTol3, JCP = 13 Hz),
2
The solution was stirred for 2 (9a1) or 20 h (9a2) and concentrated
under vacuum (1 mL). Upon addition of Et2O (15 mL) a suspension
formed, which was filtered. The solid collected was washed with Et2O
(3 × 3 mL) and dried, first by suction and then in a vacuum oven (75
°C, 5 h), to give 9a1·0.3H2O or 9a2 as a yellow solid.
137.6 (d, C6, JCP = 10 Hz), 142.7 (d, para-C, JCP = 2 Hz), 146.8
(C2), 156.1 (C1), 173.0 (C7). 31P{1H} NMR (122 MHz, CDCl3, 25
°C): δ 36.21. IR (cm−1): ν(ClO) 1095, δ(OClO) 623. ΛM
(Ω−1·cm2·mol−1): 134. Anal. Calcd for C31H35ClNO6PSPd: C,
51.53; H, 4.88; N, 1.94; S, 4.44. Found: C, 51.41; H, 4.83; N, 1.97;
S, 4.36.
3
4
9a1·0.3H2O: Yield: 77 mg, 0.39 mmol, 92%. Mp: 210 °C (dec). 1H
NMR (400 MHz, CDCl3, 25 °C): δ 1.59 (s, 0.6 H, H2O), 2.39 (vbr s,
3 H, Me, Xy), 2.45 (s, 3 H, Me8), 2.49 (vbr s, 3 H, Me, Xy), 5.51 (AB
system, 2 H, CH2, νA = 6.00, νB = 5.03, JAB = 13 Hz), 6.91 (t, 1 H,
1
6a4: Yield: 100 mg, 0.23 mmol, 80%. Mp: 173 °C (dec). H NMR
(400 MHz, CD3CN, 25 °C): δ 1.97 (s, 3 H, MeCN), 2.40 (s, 3 H,
Me8), 2.58 (s, 3 H, Me10), 5.14 (s, 2 H, CH2), 7.22−7.30 (m, 3 H, Ar),
7.34−7.36 (m, 1 H, Ar). 13C{1H} NMR (75 MHz, CD3CN, 25 °C): δ
1.8 (Me, MeCN), 13.2 (Me8), 16.5 (Me10), 78.8 (C9), 127.6 (C, Ar),
129.4 (C, Ar), 132.5 (C, Ar), 133.7 (C, Ar), 146.2 (C2), 155.8 (C1),
176.0 (C7), MeCN resonance not observed. IR (cm−1): ν(CN)
2331, ν(ClO) 1088, δ(OClO) 623. ΛM (Ω−1·cm2·mol−1): 140. Anal.
Calcd for C12H15ClN2O5PdS: C, 32.67; H, 3.43; N, 6.35; S, 7.27.
Found: C, 32.72; H, 3.27; N, 6.29; S, 6.99.
3
para-CH, Xy, JHH = 7 Hz), 7.04 (vbr m, 2 H, meta-CH, Xy), 7.31−
7.35 (m, 2 H, H11+13), 7.40 (ddd, 1 H, H4, JHH = 8 Hz, JHH = 7 Hz,
4JHH = 1 Hz), 7.44 (dd, 1 H, H3, 3JHH = 8 Hz, 4JHH = 2 Hz), 7.49 (td, 1
H, H5, 3JHH = 7 Hz, 4JHH = 2 Hz), 7.64 (dd, 1 H, H6, 3JHH = 7 Hz, 4JHH
= 1 Hz), 7.76 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 2 Hz), 8.70 (m, 1 H,
H14). (400 MHz, CDCl3, 55 °C): δ 1.45 (s, 0.6 H, H2O), 2.42 (vbr s, 6
H, Me, Xy), 2.43 (s, 3 H, Me8), 5.01, 6.00 (two vbr s, 2 H, CH2), 6.88
3
3
(t, 1 H, para-CH, Xy, 3JHH = 7 Hz), 7.02 (d, 2 H, meta-CH, Xy, 3JHH
=
3
7 Hz), 7.28−7.32 (m, 2 H, H11+13), 7.37 (ddd, 1 H, H4, JHH = 8 Hz,
Synthesis of [Pd{C,N,N′-C6H4{C(Me)NOCH2(C5H4N)-2}-2}-
(OAc)] (7a). To a solution of 3aCl (155 mg, 0.42 mmol) in
CH2Cl2 (15 mL) was added AgAcO (72 mg, 0.43 mmol). The
suspension was stirred for 15 h protected from light and then filtered
through a short pad of Celite. The solution was concentrated under
vacuum (1 mL), and Et2O (15 mL) was added. The suspension was
filtered, and the solid collected was washed with Et2O (3 × 2 mL) and
dried, first by suction and then in a vacuum oven (70 °C, 15 h), to give
7a·0.3H2O as a pale yellow solid. Yield: 153 mg, 0.39 mmol, 92%. Mp:
>140 °C (dec). 1H NMR (400 MHz,CDCl3, 25 °C): δ 1.95 (vbr s, 0.6
H, H2O), 2.28 (s, 3 H, Me, AcO), 2.33 (s, 3 H, Me8), 5.17 (s, 2 H,
CH2), 7.07 (td, 1 H, H4 or 5, 3JHH = 7 Hz, 4JHH = 1 Hz), 7.13 (td, 1 H,
4
3
4
3JHH = 7 Hz, JHH = 1 Hz), 7.42 (dd, 1 H, H3, JHH = 8 Hz, JHH = 2
Hz), 7.47 (td, 1 H, H5, 3JHH = 7 Hz, 4JHH = 2 Hz), 7.63 (dd, 1 H, H6,
4
3
4
3JHH = 7 Hz, JHH = 1 Hz), 7.73 (td, 1 H, H12, JHH = 8 Hz, JHH = 2
Hz), 8.72 (ddd, 1 H, H14, JHH = 5 Hz, JHH = 2 Hz, JHH = 1 Hz).
13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ 15.3 (Me8), 19.4 (br s,
Me, Xy), 75.6 (C9), 122.8 (para-CH, Xy), 123.6 (br s, ortho-C, Xy),
124.0 (C11), 125.3 (C13), 125.5 (C6), 127.4 (br s, meta-CH, Xy), 128.1
(C3), 128.7 (C4), 129.4 (br s, ortho-C, Xy), 132.0 (C2), 132.7 (C5),
134.4 (C1), 138.9 (C12), 148.9 (ipso-C, Xy), 150.4 (C14), 152.6 (C10),
156.7 (C7), 178.4 (CNXy). IR (cm−1): ν(CNXy) 1652. Anal.
Calcd for C23H22.6ClNO3.3Pd: C, 54.84; H, 4.52; N, 8.34. Found: C,
54.37; H, 4.16; N, 8.19. Crystals suitable for an X-ray diffraction study
were grown by slow diffusion of Et2O into a solution of 9a1 in
CH2Cl2.
3
4
5
H
4 or 5, 3JHH = 7 Hz, 4JHH = 1 Hz), 7.18 (dd, 1 H, H3 or 6, 3JHH = 7 Hz,
4JHH = 1 Hz), 7.26 (d, 1 H, H3 or 6, JHH = 7 Hz), 7.43 (d, 1 H, H11,
3
3
3
4
3JHH = 8 Hz), 7.47 (m, 1 H, H13, JHH = 8 Hz, JHH = 5 Hz, JHH = 1
Hz), 7.89 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 2 Hz), 8.75 (dd, 1 H, H14,
3JHH = 5 Hz, 4JHH = 2 Hz). 13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ
11.7 (Me8), 24.4 (Me, AcO), 75.9 (C9), 124.6 (C4 or 5), 125.1 (C11+13),
1
9a2: Yield: 80 mg, 0.18 mmol, 53%. Mp: 158 °C. H NMR (400
MHz, CDCl3, 25 °C): δ 1.84 (s, 9 H, Me, Bu), 2.34 (s, 3 H, Me8),
t
5.57 (AB system, 2 H, CH2, νA = 6.10, νB = 5.05, JAB = 13 Hz), 7.25−
7442
dx.doi.org/10.1021/om3007213 | Organometallics 2012, 31, 7434−7446

Organometallics
Article
7.30 (m, 3 H, CH, Ar and/or py-2), 7.38−7.43 (m, 3 H, CH, Ar and/
or py-2), 7.82 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 1 Hz), 8.82 (dd, 1 H,
H14, 3JHH = 5 Hz, 4JHH = 1 Hz). 13C{1H} NMR (75 MHz, CD2Cl2, 25
C24H31ClN4O5Pd: C, 48.25; H, 5.23; N, 9.38. Found: C, 48.23; H,
5.17; N, 9.47.
Synthesis of [Pd{C,N,S-C(NXy)C6H4{C(Me)NOCH2SMe}-
2}(CNXy)]ClO4 (11a1). A solution of XyNC (69 mg, 0.53 mmol)
in CH2Cl2 (9 mL) was slowly added to another of complex 6a4 (110
mg, 0.25 mmol) in the same solvent (10 mL), and the mixture was
stirred for 5 h and then filtered through a short pad of Celite. The
solution was concentrated under vacuum (2 mL), and Et2O (20 mL)
was added. The suspension was stirred in an ice/water bath for 15 min
and filtered. The solid collected was washed with Et2O (3 × 3 mL)
and dried, first by suction and then under vacuum, to give 11a1 as a
t
°C): δ 14.8 (Me8), 32.3 (Me, Bu), 56.8 (CMe3), 76.0 (C9), 124.3
(CH, Ar or py-2), 124.5 (CH, Ar or py-2), 125.4 (C13), 127.3 (CH, Ar
or py-2), 127.5 (CH, Ar or py-2), 131.8 (C2), 132.7 (CH, Ar or py-2),
134.5 (C1), 138.8 (C12), 150.2 (C14), 153.2 (C10), 156.4 (C7), 169.0
(CNtBu). IR (cm−1): ν(CNtBu) 1625. Anal. Calcd for
C19H22ClN3OPd: C, 50.68; H, 4.92; N, 9.23. Found: C, 50.35; H,
4.98; N, 9.24.
Synthesis of [Pd{C,N,N′-C(NR)C6H4{C(Me)NOCH2(C5H4N-
2)}-2}(CNR)]ClO4 (R= Xy (10a1), tBu (10a2)). A mixture containing
the appropriate complex 5 (for 10a1: 5a1, 110 mg, 0.20 mmol; for
10a2: 5a2, 15 mg, 0.22 mmol) and RNC (for 10a1: R = Xy, 32 mg,
0.24 mmol; for 10a2: R = tBu, 28 μL, 0.25 mmol) in CHCl3 (10 mL)
was stirred for 2.5 or 4.5 h (10a2) and then filtered through a short
pad of Celite. The solution was concentrated under vacuum (3 mL),
Et2O (15 mL) was added, and the suspension was filtered. The solid
collected was washed with Et2O (3 × 2 mL) and dried by suction.
10a1 was recrystallized from CH2Cl2/Et2O and 10a1 and 10a2 were
additionally dried in a vacuum oven (70 °C, 10 h) to give
10a1·0.3H2O or 10a2 as pale yellow solids.
1
yellow solid. Yield: 151 mg, 0.23 mmol, 91%. Mp: 161 °C (dec). H
NMR (400 MHz, CDCl3, 25 °C): δ 2.13 (s, 6 H, Me, XyPd), 2.16 (br s,
6 H, Me, Xyim), 2.50 (s, 3 H, Me10), 2.92 (s, 3 H, Me8), 4.7−5.4 (br s,
2 H, CH2), 6.7−7.0 (vbr s, 1 H, meta-Xyim), 6.87 (br “t”, 1 H, para-
Xyim, 3JHH = 7 Hz), 7.12 (d, 2 H, meta-XyPd, 3JHH = 8 Hz), 7.15−7.30
(vbr s, 1 H, meta-Xyim), 7.30 (t, 1 H, para-XyPd, 3JHH = 8 Hz), 7.62 (td,
3
4
3
1 H, H4, JHH = 8 Hz, JHH = 1 Hz), 7.70 (td, 1 H, H5, JHH = 8 Hz,
4JHH = 1 Hz), 7.75 (dd, 1 H, H3, 3JHH = 8 Hz, 4JHH = 1 Hz), 7.96 (dd, 1
H, H6, 3JHH = 8 Hz, 4JHH = 1 Hz). 13C{1H} NMR (100 MHz, CDCl3,
25 °C): δ 16.46 (Me8), 16.53 (Me10), 18.5 (Me, XyPd), 19.0 (br, Me,
Xyim), 75.0 (C9), 124.3 (CH, Xyim), 124.8 (br, ipso-C, XyPd), 126.6 (br,
Xyim), 127.1 (C6, Ar), 128.0 (br, Xyim), 128.2 (meta-C, XyPd), 128.6
(br, Xyim), 130.2 (C4, Ar), 130.5 (C3), 130.7 (para-C, XyPd), 130.9
(C2, Ar), 133.8 (C5, Ar), 134.2 (C1), 135.0 (ortho-C, XyPd), 138.2 (m,
CN or ipso-C(Xyim)), 150.5 (C, Xyim), 167.8 (C7), 174.3 (C
NXy). IR (cm−1): ν(CN) 2198, ν(CNXy) 1636. ΛM
(Ω−1·cm2·mol−1): 136. Anal. Calcd for C28H30ClN3O5PdS: C, 50.77;
H, 4.56; N, 6.34; S, 4.84. Found: C, 50.69; H, 4.48; N, 6.40; S, 4.55.
10a1·0.3H2O: Yield: 124 mg, 0.18 mmol, 91%. Mp: 194 °C (dec).
1H NMR (400 MHz, CDCl3, 25 °C): δ 1.7−2.7 (vbr s, 6 H, Me, Xyim),
2.10 (s, 6 H, Me, XyPd), 2.60 (s, 3 H, Me8), 5.64 (br s, 2 H, CH2),
6.4−7.4 (vbr s, 2 H, meta-Xyim), 6.88 (t, 1 H, para-Xyim, 3JHH = 7 Hz),
7.12 (d, 2 H, meta-XyPd, 3JHH3 = 8 Hz), 7.31 (t, 1 H, para-XyPd, 3JHH = 8
3
4
Hz), 7.58 (ddd, 1 H, H13, JHH = 8 Hz, JHH = 5 Hz, JHH = 2 Hz),
7.59−7.68 (m, 4 H, Ar), 7.89 (ddd, H11, JHH = 8 Hz, JHH = 2 Hz,
5JHH = 1 Hz), 8.05 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 2 Hz), 8.29 (ddd,
1 H, H14, 3JHH = 5 Hz, 4JHH = 2 Hz, 5JHH = 1 Hz). (400 MHz, CDCl3,
55 °C): δ 2.10 (s, 6 H, Me, XyPd), 2.24 (br s, 6 H, Me, Xyim), 2.60 (s, 3
H, Me8), 5.63 (s, 2 H, CH2), 6.87 (br m, 3 H, meta-Xyim + para-Xyim),
7.10 (d, 2 H, meta-XyPd, 3JHH3 = 8 Hz), 7.28 (t, 1 H, para-XyPd, 3JHH = 8
3
4
t
Synthesis of [Pd{C,N,S-C(N Bu)C6H4{C(Me)NOCH2SMe}-
2}CNtBu]ClO4 (11a2). To a solution of 6a2 (102 mg, 0.21 mmol) in
CH2Cl2 (5 mL) was added tBuNC (26 μL, 0.23 mmol). After 1.5 h of
stirring the solvent was removed under vacuum, and the residue was
stirred with n-pentane (12 mL). The suspension was filtered, and the
solid was washed with pentane (3 × 3 mL) and dried, first by suction
and then in a vacuum oven (60 °C, 10 h), to give 11a2 as a yellow
3
4
Hz), 7.56 (ddd, 1 H, H13, JHH = 8 Hz, JHH = 5 Hz, JHH = 1 Hz),
3
7.57−7.67 (m, 4 H, Ar), 7.85 (“d”, H11, JHH = 8 Hz), 8.02 (td, 1 H,
H12, JHH = 8 Hz, JHH = 1 Hz), 8.30 (“d”, 1 H, H14, JHH = 5 Hz);
(400 MHz, CDCl3, −30 °C): δ 1.94 (s, 3 H, Me, Xyim), 2.11 (s, 6 H,
Me, XyPd), 2.55 (s, 3 H, Me, Xyim), 2.62 (s, 3 H, Me8), 5.68 (AB
system, 2 H, CH2, νA = 5.73, νB = 5.62, JAB = 14 Hz), 6.56 (d, 1 H,
meta-Xyim, 3JHH = 7 Hz), 6.94 (t, 1 H, para-Xyim, 3JHH = 7 Hz), 7.17 (d,
solid. Yield: 95 mg, 0.168 mmol, 79%. Mp: 92 °C (dec). H NMR
3
4
3
1
t
(400 MHz, CDCl3, 25 °C): δ 1.57 (s, 18 H, Me, Bu) 2.52 (s, 3 H,
Me10), 2.73 (s, 3 H, Me8), 5.04 (br AB system, 2 H, CH2, νA = 4.88, νB
= 5.18, JAB = 10 Hz), 7.17 (d, 1 H, H6, 3JHH = 7 Hz), 7.45 (t, 1 H, H4,
3JHH = 8 Hz), 7.55 (t, 1 H, H5, 3JHH = 7 Hz), 7.72 (d, 1 H, H3, 3JHH = 8
2 H, meta-XyPd, JHH = 8 Hz), 7.23 (d, 1 H, meta-Xyim, JHH = 7 Hz),
3
3
3
Hz). C{1H} NMR (75 MHz, CDCl3, 25 °C): δ 15.5 (Me8), 17.2
3
3
7.36 (t, 1 H, para-XyPd, JHH = 8 Hz), 7.60 (ddd, 1 H, H13, JHH = 8
Hz, 3JHH = 5 Hz, 4JHH = 1 Hz), 7.65−7.68 (m, 4 H, Ar), 7.96 (“d”, H11,
3JHH = 8 Hz), 8.09 (td, 1 H, H12, 3JHH = 8 Hz, 4JHH = 1 Hz), 8.27 (“d”,
1 H, H14, 3JHH = 5 Hz). 13C{1H} NMR (100 MHz, CDCl3, 25 °C): δ
15.9 (Me8), 18.7 (Me, XyPd), 18.9 (br, Me, Xyim), 76.0 (C9), 124.1
(para-C, Xyim), 124.6 (br, ipso-C, XyPd), 126.1 (br, ortho-C, Xyim),
126.4 (C3, 4, 5 or 6), 126.9 (C13), 127.1 (C11), 128.2 (meta-C, XyPd),
129.6 (C, Ar), 130.7 (C, Ar), 130.8 (para-C, XyPd), 131.7 (C2), 132.5
(C1), 133.4 (C, Ar), 135.5 (ortho-C, XyPd), 138.5 (m, CN), 141.3
(C12), 150.4 (ipso-C, Xyim), 150.5 (C14), 153.0 (C10), 159.8 (C7),
174.8 (CNXy), meta-C, Xyim not observed. IR (cm−1): ν(CN)
2198, ν(CNXy) 1630. ΛM (Ω−1·cm2·mol−1): 121. Anal. Calcd for
C32H31.6ClN4O5.3Pd: C, 55.00; H, 4.56; N, 8.02. Found: C, 54.60; H,
4.81; N, 7.94.
t
t
(Me10), 29.8 (Me, Bu), 31.1 (Me, Bu), 56.6 (CMe3), 59.6 (CMe3),
75.7 (C9), 124.7 (C6), 128.7 (C4), 129.4 (C3), 130.4 (C2), 133.5 (C5),
135.0 (C1), 161.1 (CNtBu), 166.1 (C7). IR (cm−1): ν(CN) 2210,
ν(ClO) 1090, δ(OClO) 623. ΛM (Ω−1·cm2·mol−1): 127. Anal. Calcd
for C20H30ClN3O5PdS: C, 42.41; H, 5.34; N, 7.42; S, 5.66. Found: C,
C, 42.53; H, 5.06; N, 7.43; S, 5.80.
Synthesis of [Pd{C,N,C′-C6H4{C(Me)NOC(CO2Me)C-
(CO2Me)}-2}(tBubpy)] (12). To a solution of 2a (114 mg, 0.28
mmol) in CH2Cl2 (10 mL) was added dimethyl acetylenedicarboxylate
(36 μL, 0.29 mmol). The resulting solution was stirred for 1.5 h and
filtered through a short pad of Celite, the solution was concentrated
under vacuum (1 mL), and a mixture of Et2O and n-pentane (1:3, 20
mL) was added. The suspension was filtered, and the solid was washed
successively with the same solvent mixture (3 × 3 mL) and with Et2O
(3 mL) to give 12 (131 mg, 0.20 mmol, 71%). Mp: 167 °C. 1H NMR
10a2: Yield: 129 mg, 0.22 mmol, 97%. Mp: 139 °C (dec). 1H NMR
(400 MHz, CDCl3, 25 °C): δ 1.60 (s, 9 H, Me, tBu), 1.67 (s, 9 H, Me,
tBu), 2.42 (s, 3 H, Me8), 5.54 (AB system, 2 H, CH2, νA = 5.73, νB =
5.35, JAB = 14 Hz), 7.09 (d, 1 H, H6, 3JHH = 7.5 Hz), 7.41−7.45 (m, 2
t
(400 MHz, CDCl3, 25 °C): δ 1.37 (s, 18 H, Me, Bu), 2.24 (s, 3 H,
Me8), 3.47 (s, 3 H, CO2Me), 3.77 (s, 3 H, CO2Me), 6.11−6.15 (m, 1
H, H4, 5 or 6), 6.78−6.83 (m, 2 H, H4, 5 and/or 6), 6.84−6.87 (m, 1 H,
H3), 7.30 (dd, 2 H, H18, tBubpy, 3JHH = 6 Hz, 4JHH = 2 Hz), 8.64 (d, 1
H, H19, tBubpy, 3JHH = 6 Hz), 8.66 (d, 2 H, H16, tBubpy, 4JHH = 2 Hz).
3C{1H} NMR (100 MHz, CDCl3, 25 °C): δ 11.7 (Me8), 30.3 (Me,
tBu), 35.3 (CMe3), 50.7 (CO2Me), 52.2 (CO2Me), 121.2 (C18), 121.8
(C16), 123.8 (C4, 5 or 6), 125.4 (C3), 130.4 (C4, 5 or 6), 132.8 (C4, 5 or 6),
144.0 (C9 or 10), 147.8 (C2), 150.0 (C19), 152.0 (C9 or 10), 157.6 (C15),
157.9 (CO2Me), 161.4 (C17), 163.8 (C1), 169.4 (C7), 173.3 (CO2Me).
IR (cm−1): ν(CO) 1718, 1688. Anal. Calcd for C32H37N3O5Pd: C,
59.13; H, 5.74; N, 6.46. Found: 59.01; H, 5.79; N, 6.42.
3
H, H3+4), 7.47−7.53 (m, 1 H, H5), 7.74 (d, 1 H, H11, JHH = 8 Hz),
7.78 (ddd, 1 H, H13, 3JHH = 8 Hz, 3JHH = 5 Hz, 4JHH = 1 Hz), 8.04 (td,
1 H, H12, 3JHH = 8 Hz, 4JHH = 1 Hz), 8.39 (d, 1 H, H14, 3JHH = 5 Hz).
13C{1H} NMR (100 MHz, CDCl3, 25 °C): δ 15.1 (Me8), 29.8 (Me,
t
tBuPd), 31.1 (Me, Buim), 56.6 (CMe3), 59.8 (CMe3), 76.1 (C9), 124.1
(C6), 126.8 (C11), 127.2 (C13), 128.5 (C3), 129.0 (C4), 131.2 (C2),
133.1 (C5), 133.8 (C1), 140.8 (C12), 150.7 (C14), 153.0 (C10), 158.7
(C7), 164.0 (CNtBu). IR (cm−1): ν(CN) 2210, ν(ClO) 1092,
ν(OClO) 625. ΛM (Ω−1·cm2·mol−1): 134. Anal. Calcd for
7443
dx.doi.org/10.1021/om3007213 | Organometallics 2012, 31, 7434−7446

Organometallics
Article
Synthesis of [Pd{C,N,C′-C6H4{C(Me)NOC(CO2Me)C-
Crystallography data (excluding structure factors) for the structures
reported in this paper have been deposited with the Cambridge
Crystallographic Data Centre, CCDC numbers 891028 (3aBr),
891029 (3bCl), 891030 (5a3), 891031 (6a1), 891032 (8a·CH2Cl2)
891033 (9a1), and 891968 (13). Copies of these data can be obtained
free of charge on application to the Director, CCDC, 12 Union Road,
Cambridge CB2 IEZ, UK (fax: +44-1223-336033; e-mail: deposit@
ccdc.ac.uk; or http://www.ccdc.cam.ac.hk).
t
(CO2Me)}-2}(L)] (L = ClCH2py-2 (13), XyNC (14), BuNC (15)).
To a solution of 2a (for 13, 160 mg, 0.32 mmol; for 14, 102 mg, 0.20
mmol; for 15, 124 mg, 0.24 mmol) in CH2Cl2 (10 mL) was added
dimethyl acetylenedicarboxylate (for 13, 40 μL, 0.32 mmol; for 14, 26
μL, 0.21 mmol; for 15, 32 μL, 0.26 mmol). The resulting solution was
stirred for 1 h, and the appropriate ligand was then added (for 13,
ClCH2py-2 prepared in situ from (ClCH2pyH-2)Cl (66 mg, 0.4 mmol)
and KtBuO (44 mg, 0.37 mmol) in CH2Cl2 (5 mL); for 14, CNXy, 27
t
mg, 0.21 mmol; for 15, BuNC, 56 μL, 0.50 mmol). After 1.5 or 2 h
ASSOCIATED CONTENT
* Supporting Information
CIF files and tables giving crystal data. This material is available
■
(15) of stirring, the reaction mixture was filtered through a short pad
of Celite. For 13, the solution was concentrated under vacuum (1
mL), Et2O (15 mL) was added, and the suspension was filtered to
remove some impurities. The filtrate was concentrated to dryness, the
residue was dissolved in CH2Cl2 (2 mL), and a mixture of Et2O/n-
pentane (1:3, 20 mL) was added. The suspension was filtered, and the
solid collected was successively washed with the same mixture of
solvents (3 × 3 mL) and with Et2O (3 mL). For 14 and 15, the
solution was concentrated (0.5−1 mL), Et2O (15 mL) was added, the
suspension was filtered, and the solid collected was washed with Et2O
(3 × 2 mL). The yellow compounds were all dried by suction, and 15
was additionally dried under vacuum.
S
free of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: jvs1@um.es. Web: http://www.um.es/gqo/.
■
Notes
The authors declare no competing financial interest.
1
13: Yield: 83 mg, 0.16 mmol, 52%. Mp: 163 °C (dec). H NMR
ACKNOWLEDGMENTS
■
(400 MHz, CDCl3, 25 °C): δ 2.36 (s, 3 H, Me8), 3.36 (s, 3 H,
CO2Me), 3.75 (s, 3 H, CO2Me), 5.21 (AB system, 2 H, CH2, νA =
5.20, νB = 5.23, JAB = 14 Hz), 6.25−6.29 (m, 1 H, H4 or 6), 6.94−7.01
(m, 2 H, H5+4 or 6), 7.03−7.07 (m, 1 H, H3), 7.37 (ddd, 1 H, H18, py-2,
We thank the Ministerio de Educacion
FEDER (CTQ2007-60808/BQU), and Fundacio
(04539/GERM/06 and 03059/PI/05) for financial support
́
y Ciencia (Spain),
n Seneca
́
́
3JHH = 7 Hz, 3JHH = 6 Hz, 4JHH = 1 Hz), 7.85 (d, 1 H, H16, py-2, 3JHH
=
and for a grant to A.A.-L.
8 Hz), 7.92 (td, 1 H, H17, py-2, 3JHH = 8 Hz, 4JHH = 2 Hz), 8.81 (d, 1
3
3
H, H19, JHH = 6 Hz). C{1H} NMR (100 MHz, CDCl3, 25 °C): δ
12.0 (Me8), 46.0 (CH2), 50.8 (CO2Me), 52.1 (CO2Me), 123.8 (C18),
124.6 (C16), 124.7 (C4 or 6), 126.3 (C3), 131.0 (C5), 132.7 (C4 or 6),
138.0 (C17), 145.0 (C9 or 10), 148.7 (C2), 150.1 (C9 or 10), 151.3 (C19),
157.5 (C15), 157.7 (CO2Me), 164.2 (C1), 170.2 (C7), 173.0 (CO2Me).
IR (cm−1): ν(CO) 1721, 1702. Anal. Calcd for C20H19ClN2O5Pd:
C, 47.17; H, 3.76; N, 5.50. Found: C, 46.83; H, 3.79; N, 5.35. Crystals
suitable for an X-ray diffraction study were grown by slow diffusion of
n-pentane into a solution of 13 in acetone.
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■
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14: Yield: 70 mg, 0.14 mmol, 68%. Mp: 165 °C (dec). H NMR
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3
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1
15: Yield: 71 mg, 0.15 mmol, 63%. Mp: 153 °C (dec). H NMR
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t
(400 MHz, CDCl3, 25 °C): δ 1.58 (s, 9 H, Me, Bu), 2.33 (s, 3 H,
Me8), 3.76 (s, 6 H, CO2Me), 6.98−7.04 (m, 2 H, H3+4), 7.08 (td, 1 H,
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1
(C5), 134.3 (1:1:1, t, CN, JCN = 17 Hz), 136.5 (C6), 147.0
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