Comparative study of the reactivity of cyclopalladated compounds containing [C(sp2,ferrocene),N,N′]- terdentate ligands versus symmetric alkynes

Article abstract of DOI:10.1021/om021036y

A comparative study of the reactivity of the cyclopalladated compounds [Pd{[(η⁵-C₅H₃)- CH=N(CH₂)_nNMe₂]Fe(η⁵- C₅H₅)} Cl] (n = 2 (2a), 3 (2b)) containing a [C(sp²,ferrocene),N,N′]^- terdentate group with the symmetric alkynes R¹C≡CR¹ (with R¹ = Ph, Et, CO₂Me) is reported. In the presence of Tl[BF₄], these reactions have allowed us to isolate and characterize ionic palladacycles of the general formula [Pd{[(R¹C=CR¹)₂ (η⁵-C₅ H₃)CH=N(CH₂)_nNMe₂]Fe (η⁵-C₅H₅)}] [BF₄] (n = 2, R¹ = Ph (4a), Et (5a), CO₂Me (6a); n = 3, R¹ = Ph (4b), Et (5b), CO₂Me (6b)) and the neutral derivatives [Pd{[(MeO₂CC=CCO₂Me)(η⁵-C₅H ₃)-CH=N(CH₂)_nNMe₂]Fe (η⁵-C₅H₅)}Cl] (n = 2 (7a), 3 (7b)) and [Pd{[(MeO₂CC=CCO₂Me)₂ (η⁵-C₅H₃)CH=N(CH₂)₃NM e₂]Fe(η⁵-C₅H₅)}Cl] (8b). Compounds 4-6 and 8b arise from the bis insertion of the corresponding alkynes into the σ[Pd-C(sp²,ferrocene)] bond of 2, while the formation of 7 involved the insertion of only one molecule of MeO₂CC≡CCO₂Me. The mode of binding of the butadienyl unit is η³ in 4-6 and η¹ in 8b. Compounds 7 could also be isolated in a higher yield from the reaction of equimolar amounts of MeO₂CC≡CCO₂Me and the corresponding compound 2 in refluxing CH₂Cl₂. The X-ray crystal structures of 4a,b, 5b, and 8b are also reported and confirm the mode of binding of the ferrocenyl ligand to the palladium in these compounds.

Full text of DOI:10.1021/om021036y

2396
Organometallics 2003, 22, 2396-2408
Com p a r a tive Stu d y of th e Rea ctivity of Cyclop a lla d a ted
Com p ou n d s Con ta in in g [C(sp 2,fer r ocen e),N,N′]-
Ter d en ta te Liga n d s ver su s Sym m etr ic Alk yn es
Sonia Pe´rez,† Concepcio´n Lo´pez,*,† Amparo Caubet,† Adam Pawełczyk,†
Xavier Solans,‡ and Merce` Font-Bard´ıa‡
Departament de Quimica Inorga`nica, Facultat de Qu´ımica, and Departament de
Cristallografia, Mineralogia i Dipo`sits Minerals, Facultat de Geolog´ıa,
Universitat de Barcelona, Mart´ı i Franque`s s/ n, 08028-Barcelona, Spain
Received December 22, 2002
A comparative study of the reactivity of the cyclopalladated compounds [Pd{[(η5-C5H3)-
CHdN(CH2)nNMe2]Fe(η5-C5H5)}Cl] (n ) 2 (2a ), 3 (2b)) containing a [C(sp2,ferrocene),N,N′]-
terdentate group with the symmetric alkynes R1CtCR1 (with R1 ) Ph, Et, CO2Me) is
reported. In the presence of Tl[BF4], these reactions have allowed us to isolate and
characterize ionic palladacycles of the general formula [Pd{[(R1CdCR1)2(η5-C5H3)CHd
N(CH2)nNMe2]Fe(η5-C5H5)}][BF4] (n ) 2, R1 ) Ph (4a ), Et (5a ), CO2Me (6a ); n ) 3, R1 ) Ph
(4b), Et (5b), CO2Me (6b)) and the neutral derivatives [Pd{[(MeO2CCdCCO2Me)(η5-C5H3)-
CHdN(CH2)nNMe2]Fe(η5-C5H5)}Cl] (n ) 2 (7a ), 3 (7b)) and [Pd{[(MeO2CCdCCO2Me)2(η5-
C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)}Cl] (8b). Compounds 4-6 and 8b arise from the bis
insertion of the corresponding alkynes into the σ[Pd-C(sp2,ferrocene)] bond of 2, while the
formation of 7 involved the insertion of only one molecule of MeO2CCtCCO2Me. The mode
of binding of the butadienyl unit is η3 in 4-6 and η1 in 8b. Compounds 7 could also be
isolated in a higher yield from the reaction of equimolar amounts of MeO2CCtCCO2Me and
the corresponding compound 2 in refluxing CH2Cl2. The X-ray crystal structures of 4a ,b,
5b, and 8b are also reported and confirm the mode of binding of the ferrocenyl ligand to the
palladium in these compounds.
In tr od u ction
metallomesogens or antitumor drugs containing palla-
dacycles have been reported,3,4 and the applications of
chiral cyclopalladated complexes for the determination
of enantiomeric excesses of chiral reagents have also
been described.5 More recently, some articles focused
on the catalytic activities of these sorts of compounds
have also been reported.6 However, one of the main
interests of cyclopalladated derivatives is based on their
use either as building blocks for the preparation of
macromolecules7 or as precursors for organic or orga-
nometallic synthesis.8,9 For instance, cyclopalladated
compounds show high reactivity toward a wide variety
of substrates such as CO, isonitriles, alkenes, and
alkynes. Reactions of this kind have provided novel
procedures for the preparation of organic compounds.8
Mono, bis, and even tris insertions of alkynes into the
The synthesis, characterization, and study of cyclo-
palladated complexes1 has attracted great interest dur-
ing the past decade due to a variety of interesting
applications in different areas.2-11 Some examples of
* To whom correspondence should be addressed. E-mail:
conchi.lopez@qi.ub.es.
† Departament de Quimica Inorga`nica, Facultat de Qu´ımica.
‡ Departament de Cristallografia, Mineralogia i Dipo`sits Minerals,
Facultat de Geolog´ıa.
(1) (a) Newkome, R. G.; Puckett, G. E.; Gupta, V. K.; Kiefer, G. E.
Chem. Rev. 1986, 86, 451 and references therein. (b) Dunina, V. V.;
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1988, 57, 250 and references therein. (c) Ryabov, A. D. Chem. Rev.
1990, 90, 403 and references therein. (e) Omae, I. Coord. Chem. Rev.
1988, 83, 137 and references therein.
(2) (a) Omae, I. Applications of Organometallic Compounds, Wiley:
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Colorants: Synthesis and Structure; Peters, A. E., Freeman, H. S., Eds.;
Blackie Academic: London, 1995; Vol. 3, p 1.
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Alonso, C. Appl. Organomet. Chem. 1993, 7, 57. (b) Navarro-Ranninger,
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1996, 35, 5181.
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1350.
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A. D. Synthesis 1985, 233.
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tallics 2002, 21, 2041. (b) Vicente, J .; Abad, J . A.; Gil-Rubio, J .; J ones,
P. G. Organometallics 1995, 14, 2677. (c) Vicente, J .; Saura-Llamas,
I.; De Arellano, M. C. R. J . Chem. Soc., Dalton Trans. 1995, 2529. (d)
Vicente, J .; Saura-Llamas, I.; Palin, M. G. J . Chem. Soc., Dalton Trans.
1995, 2535.
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metallics 1993, 12, 1167. (b) Pfeffer, M.; Rotteveel, M. A.; Sutter, J .
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therein. (b) Albert, J .; Cadena, J . M.; Granell, J . R.; Solans, X.; Font-
Bard´ıa, M. Tetrahedron: Asymmetry 2000, 11, 1943.
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10.1021/om021036y CCC: $25.00 © 2003 American Chemical Society
Publication on Web 05/09/2003

Cyclopalladated Compounds
Ch a r t 1
Organometallics, Vol. 22, No. 12, 2003 2397
Sch em e 1a
a
Abbreviations: R2 ) H, Me, Ph; R3 ) phenyl, benzyl, 2,2′-
Ta ble 1. Electr on ic a n d Ster ic P a r a m eter s for th e
Su bstitu en ts (R1) on th e Alk yn esa
biphenyl; R1 ) Ph, Et. Legend: (i) diphenylacetylene or hex-
3-yne in a alkyne/Pd molar ratio of 2, in refluxing CH2Cl2 or
CHCl3 for 2 h, followed by SiO2 column chromatography.
R1
σI
σR
Es′(CH)
Ph
Et
CO2Me
0.12
-0.01
0.21
0.10
-0.14
0.16
3.0
2.0
4.0
Resu lts a n d Discu ssion
a
Alk yn e In ser tion s. In a first attempt to study the
reactivity of compounds 2 with the alkynes, we decided
to use the procedures described previously for the
preparation of [Pd{[(R1CdCR1)2(η5-C5H3)C(R2)dNR3]Fe-
(η5-C5H5)}Cl] (R1 ) Et, Ph; R2 ) H, Me, Ph; R3 ) phenyl,
benzyl groups),12 which consisted of the reaction of the
corresponding bis(µ-chloro) cyclopalladated derivative
[Pd{[(η5-C5H3)C(R2)dNR3]Fe(η5-C5H5)}(µ-Cl)]2 (1) with
PhCtCPh or EtCtCEt (Pd/alkyne molar ratio of 2) in
refluxing CH2Cl2 for 2 h (Scheme 1).12
However, when [Pd{[(η5-C5H3)CHdN(CH2)nNMe2]Fe-
(η5-C5H5)}Cl] (n ) 2 (2a ), 3 (2b)) (Chart 1) was treated
separately with PhCtCPh or EtCtCEt (alkyne/Pd
molar ratio of 2) in refluxing CH2Cl2 (or CHCl3) for 2 h,
the starting materials were recovered unchanged and
no evidence of any chemical change was detected by
NMR spectroscopy, even when the refluxing period was
increased up to 24 h. These results are in sharp contrast
with those reported previously for the dimeric com-
pounds [Pd{[(η5-C5H3)C(R2)dNR3]Fe(η5-C5H5)}(µ-Cl)]2
(1),12 thus suggesting that the bis(µ-chloro) cyclopalla-
dated complexes are more prone to undergo the double
insertion of the alkynes R1CtCR1 (with R1 ) Ph, Et)
than compounds 2.
According to the mechanistic studies reported by
Ryabov et al.16 on the bis(insertion) of alkynes into the
σ[Pd-C(sp2,aryl)] bond of cyclopalladated complexes, in
these kinds of reactions, the first step of the process
consists of the coordination of the alkyne to the Pd(II)
in a cis arrangement to metalated carbon. The smaller
proclivity of 2a ,b to react with diphenylacetylene or hex-
3-yne, when compared with that of compounds 1, could
be related to the different lability of the Pd-Cl bond in
the adjacent position to the metalated carbon.
To check this hypothesis, we decided to elucidate if
the removal of the chlorine group in 2, upon the addition
of thallium(I) salts, could enhance the reactivity of these
substrates with PhCtCPh or EtCtCEt. With this aim,
and as a first approach to the problem, 2a was treated
separately in acetone with a 50% excess of Tl[BF4] at
room temperature (ca. 20 °C) for 2 h. During this period,
the precipitation of TlCl was observed. The subsequent
removal of the TlCl (∼26 mg) and the excess of Tl[BF4]
and the concentration of the resulting solution to
dryness on a rotary evaporator gave a red-brown residue
(hereinafter referred to as 3a ). This material was then
treated separately with diphenylacetylene in a alkyne/
σI and σR are the inductive (para) and mesomeric (para)
parameters of the substituent R1. Positive σ values indicate
electron-withdrawing character of the substituent, while negative
values correspond to electron-donor groups. Es′(CH) values are
Charton’s steric parameters for R1 calculated according to struc-
tural data. All the values presented in this table were taken from
ref 15.
σ[Pd-C(sp2,aryl)] bond of cyclopalladated complexes
containing organic ligands have been extensively stud-
ied over the last few years,8-10 and a few examples of
the mono and bis insertion of internal alkynes into the
σ[Pd-C(sp2,ferrocene)] bond of the bis(µ-chloro) cyclo-
palladated compounds [Pd{[(η5-C5H3)C(R2)dNR3]Fe(η5-
C5H5)}(µ-Cl)]2 (1) (Chart 1) containing bidentate [C(sp2,-
ferrocene),N]- ferrocenyl Schiff bases have also been
reported.10-12
Cyclopalladated complexes with a [C(sp2,ferrocene),-
N,N′]- terdentate ligand are scarce,13,14 and to the best
of our knowledge, the reactivity of the σ[Pd-C(sp2,-
ferrocene)] bond with alkynes in these types of com-
pounds has not been studied so far.
In view of these facts, we were prompted to study the
reactions of compounds [Pd{[(η5-C5H3)CHdN(CH2)n-
NMe2]Fe(η5-C5H5)}Cl] (n ) 2 (2a ), 3 (2b)) (Chart 1) with
three different internal alkynes R1CtCR1 (where R1
represents Et, Ph, or CO2Me), which differ in the
electronic and steric properties of the substituents R1
(Table 1).15 This type of study could be useful to
elucidate the relative influence of: (a) the mode of
binding of the ferrocenyl ligand, [C(sp2,ferrocene),N]-
in 1 or [C(sp2,ferrocene),N,N′]- in 2, (b) the substituents
on the alkyne (electron-donating/electron-withdrawing
character as well as their bulk), (c) the type of σ(Pd-
Cl) bond in 1 or 2, and even (d) the relevancy of the
size of the chelate formed by the binding of the two
nitrogen atoms to the palladium, a five- (in 2a ) or a six-
membered ring (in 2b), upon the nature of the final
product.
(12) (a) Lo´pez, C.; Tramuns, D.; Solans, X. J . Organomet. Chem.
1994, 471, 265. (b) Benito, M.; Lo´pez, C.; Morvan, X.; Solans, X.; Font-
Bard´ıa, M. J . Chem. Soc., Dalton Trans. 2000, 4470. (c) Lo´pez, C.;
Bosque, R.; Solans, X.; Font-Bard´ıa, M.; Silver, J .; Fern, G. J . Chem.
Soc., Dalton Trans. 1995, 1839. (d) Benito, M.; Lo´pez, C.; Solans, X.;
Font-Bard´ıa, M. Tetrahedron: Asymmetry 1998, 9, 4219. (e) Bosque,
R.; Benito, M.; Lo´pez, C. New J . Chem. 2001, 25, 827.
(13) Lo´pez, C.; Caubet, A.; Pe´rez, S.; Solans, X.; Font-Bard´ıa, M. J .
Organomet. Chem. 2001, 651, 105.
(14) Lo´pez, C.; Caubet, A.; Solans, X.; Font-Bard´ıa, M. J . Organomet.
Chem. 2000, 598, 87.
(15) Hansch, C.; Leo, A.; Koekman, D. Exploring QSAR: Hydro-
phobic, Electronic and Steric Constants; American Chemical Society:
Washington, DC, 1995.
(16) Ryabov, A. D.; van Eldik, R.; Le Borgne, G.; Pfeffer, M.
Organometallics 1993, 12, 1386.

2398 Organometallics, Vol. 22, No. 12, 2003
Pe´rez et al.
Sch em e 2a
Ch a r t 2
unreacted cyclopalladated derivative 2a or 2b, while the
other was identified according to elemental analyses,
mass spectra (FAB+), and infrared and NMR spectros-
copy as [Pd{[(EtCdCEt)2(η5-C5H3)CHdN(CH2)nNMe2]-
Fe(η5-C5H5)}][BF4] (n ) 2 (5a ), 3 (5b) (Scheme 2 and
Chart 2, respectively)), which arise from the bis inser-
tion of the hex-3-yne into the σ[Pd-C(sp2,ferrocene)]
bond. The X-ray crystal structure of 5b (see below)
confirmed the arrangement of the ethyl groups depicted
in Chart 2 and a η3 mode of binding of the butadienyl
unit. It should be noted that the yield of 5a was very
low when the refluxing period was equal to 2 h, but it
could be improved by using longer reaction periods (6
h). This result suggests that for 2b the bis insertion of
the hex-3-yne requires milder experimental conditions
than for 2a .
a
Legend: (i) Tl[BF4] in acetone (molar ratio Tl(I)/2a ) 1.5)
at room temperature, followed by the removal of the TlCl by
filtration and the unreacted Tl[BF4] using CH2Cl2 and subse-
quent evaporation to dryness; (ii) The corresponding alkyne
diphenylacetylene or hex-3-yne in a alkyne/Pd molar ratio of
2, in refluxing CH2Cl2, followed by SiO2 column chromatog-
raphy (see text).
palladium(II) molar ratio of 2, in refluxing CH2Cl2 for
2 h (Scheme 2). Two different compounds (red and
orange-brown solids) were isolated after workup by
short SiO2 column chromatography. The red solid was
obtained from the band eluted with CH2Cl2, and its
characterization data were identical with those of the
starting material [Pd{[(η5-C5H3)-CHdN(CH2)2NMe2]Fe-
(η5-C5H5)}Cl] (2a ). The other solid, which was obtained
after the elution with a CH2Cl2/MeOH mixture (100/1),
was characterized by elemental analyses, FAB+ mass
spectra, and infrared spectroscopy as well as one- and
two-dimensional NMR spectroscopy. All these data were
consistent with those expected for [Pd{[(PhCdCPh)2(η5-
C5H3)CHdN(CH2)2NMe2]Fe(η5-C5H5)][BF4] (4a) (Scheme
2), which arises from the bis insertion of PhCtCPh. The
X-ray crystal structure of this complex (vide infra)
confirmed these results as well as the arrangement of
the phenyl rings depicted in Scheme 2 and the η3 mode
of binding of the butadienyl unit.
Similarly, the treatment of 2b in acetone with a 50%
excess of Tl[BF4] at room temperature (ca. 20 °C),
followed by the removal of the TlCl formed and the
excess of Tl[BF4], gave (after concentration to dryness)
a red-brown residue, hereinafter referred to as 3b.
Further treatment of 3b with PhCtCPh (in a alkyne/
palladium(II) molar ratio of 2) in refluxing CH2Cl2 for
2 h led, after workup of the column, to unreacted 2b
and an additional orange-red solid which was identified
on the basis of elemental analyses, mass spectrometry,
and infrared and NMR spectra (see Experimental Sec-
tion), as well as by X-ray diffraction (vide infra), as [Pd-
{[(PhCdCPh)2(η5-C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)}]-
[BF4] (4b) (Chart 2).
In these reactions the amounts of 2a or 2b recovered
did not vary significantly when (a) longer refluxing
periods (up to 10 h) were used or (b) the starting
materials 2 were treated with Tl[BF4] in tetrahydrofu-
ran prior to the addition of the alkyne.
More interesting are the results obtained in the
reactions of 2a with MeO2CCtCCO2Me under identical
experimental conditions. In this case the compounds
[Pd{[(MeO2CCdCCO2Me)2(η5-C5H3)CHdN(CH2)2NMe2]-
Fe(η5-C5H5)}][BF4] (6a ) and [Pd{[(MeO2CCdCCO2Me)-
(η5-C5H3)CHdN(CH2)nNMe2]Fe(η5-C5H5)}Cl] (7a ) were
obtained exclusively (Scheme 3) and no evidence for the
presence of unreacted 2a was detected by NMR spec-
troscopy. The deep orange complex 6a formed by the
bis insertion of the alkyne and its cationic array is
similar to those of 4a and 5a , except for the nature of
the substituents R1 on the η3-butadienyl fragment, while
compound 7a , which is a bright yellow solid, contains a
seven-membered palladacycle formed by the insertion
of one molecule of MeO2CCtCCO2Me.
When the reaction was performed under identical
experimental conditions, but using 2b (269 mg) as
starting material, three compounds could be isolated,
after the workup of the SiO2 column. The first eluted
band produced a yellow product whose characterization
data agreed with those expected for [Pd{[(MeO2CCd
CCO2Me)(η5-C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)}Cl]
(7b). A small amount (∼15 mg) of another yellow
complex (hereinafter referred to as 8b) was obtained
after concentration of the second eluted band, and its
elemental analyses, mass spectrometry, and IR and
NMR spectra were consistent with those of [Pd{[(MeO2-
CCdCCO2Me)2(η5-C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)}-
Cl] (8b) (Chart 3), which arises from the bis insertion
of the alkyne into the σ[Pd-C(sp2,ferrocene)] bond. The
crystal structure of 8b (vide infra) reveals an η1 mode
It should be noted that the yields of 4a and 4b were
clearly smaller than those reported for [Pd{[(R1CdCR1)2-
(η5-C5H3)C(R2)dNR3]Fe(η5-C5H5)}Cl] described previ-
ously.12
When the reactions were performed under identical
experimental conditions but using hex-3-yne and 2a (or
2b) as starting materials, two palladium(II) compounds
were also isolated in each case; one of them was the

Cyclopalladated Compounds
Sch em e 3a
Organometallics, Vol. 22, No. 12, 2003 2399
Sch em e 4a
a
Legend: (i) equimolar amount of the alkyne, in refluxing
CH2Cl2 (21 h) followed by SiO2 column chromatography.
of 6b (in CDCl3) changed with time. Initially, the
spectrum of a freshly prepared sample showed a singlet
at δ 8.52 ppm, but after 2 days of storage at ca. 20 °C,
a group of five singlets at δ 8.84, 8.52, 7.96, 7.92, and
7.74 ppm of relative intensities 1/1.8/0.7/1.2/1.7 could
be detected. For longer periods (10 days) the intensity
of the signal at δ 7.74 ppm increased while that due to
the imine proton of 6b (at δ 8.52 ppm) vanished, as did
the other resonances of 6b. In addition, a considerable
widening of the remaining signals was also observed.
These findings suggested that a chemical change involv-
ing the decomposition of 6b was occurring. This type of
behavior was not observed for 6a , in which the chelate
is a five-membered ring, thus indicating that the
incorporation of an additional -CH2- fragment in the
backbone reduces the stability of the compounds [Pd-
{[(MeO2CCdCCO2Me)2(η5-C5H3)CHdN(CH2)nNMe2]Fe-
(η5-C5H5)}][BF4] (n ) 2, 3).
a
Legend: (i) Tl[BF4] in acetone; (ii) in a alkyne/Pd molar
ratio of 2, in refluxing CH2Cl2, followed by SiO2 column
chromatography (see text).
Ch a r t 3
On the other hand, it is interesting to point out that
in the reactions of 2 with MeO2CCtCCO2Me no evi-
dence for the presence of the starting cyclopalladated
complex was detected by NMR spectroscopy. This find-
ing is in sharp contrast with that obtained when the
reactions were carried out using diphenylacetylene or
hex-3-yne and may be ascribed to the greater reactivity
of MeO2CCtCCO2Me when compared with that of
EtCtCEt or PhCtCPh.18
Compounds 7 could be isolated in a higher yield when
the corresponding complex (2a or 2b) was treated with
an equimolar amount of MeO2CCtCCO2Me in refluxing
CH2Cl2 and subsequently purified by SiO2 column
chromatography (Scheme 4). It is worth remarking that
complex 7b could be isolated after 6 h of reflux, but for
7a , the NMR spectrum of the crude product obtained
after this refluxing period indicated the presence of the
starting material 2a and 7a in the molar ratio 2a /7a )
6. However, an increase of the refluxing period (up to
21 h) produced a decrease of the relative proportion 2a /
7a . These results suggest that 2a is less reactive than
2b versus the alkyne MeO2CCtCCO2Me.
of binding of the inserted butadienyl unit and the cis
arrangement of the -CO2Me substituents in the two
>CdC< groups, shown in Chart 3. The third component
was obtained after the elution of the column with a CH2-
Cl2/MeOH (100/1.5) mixture. This produced the release
of a deep violet band, which led after concentration to
dryness to a purple solid. Its infrared spectrum showed
the typical bands of the [BF4]- anion,17 and its FAB+
mass spectrum showed a peak at m/z 688, which could
be ascribed to the "[Pd{[(MeO2CCdCCO2Me)2(η5-C5H3)-
CHdN(CH2)3NMe2]Fe(η5-C5H5)}]+" cation. In addition,
1
its H and 13C{1H} NMR spectroscopic data were very
similar to those of 6a , except for the presence of
additional multiplets due to the protons of the central
methylene unit of the “dN(CH2)3NMe2” moiety. On this
basis, we tentatively propose for this complex the
formula [Pd{[(MeO2CCdCCO2Me)2(η5-C5H3)CHdN-
(CH2)3NMe2]Fe(η5-C5H5)}][BF4] (6b). Attempts to char-
acterize 6b by elemental analyses failed, due to the low
stability of this product in the solid state. The purple
color of a freshly prepared solid sample of 6b turned
brownish in a few hours, and its solubility in CHCl3
decreased substantially. A similar change of color was
observed in CHCl3 solutions, and the 1H NMR spectrum
However, when the reaction was performed using 2b
and MeO2CCtCCO2Me (in a 1/2 molar ratio), compound
7b was isolated and the formation of traces of the bis
insertion derivative 8b was also detected by NMR
spectroscopy. In contrast with these results, when the
reaction was carried out using 2a as reagent and longer
reaction periods (up to 4 days), the presence of
(18) (a) Houben-Weyl: Methoden der Organische Chemie: Alkine,
Di und Polyne, Kumulene; Mu¨ller, E., J a¨ger, V., Murray, M., Niedballa,
V., Eds.; Georg Thieme Verlag: Stuttgart, Germany, 1977; Vol. 5/2a,
p
33. (b) Comprehensive Organic Chemistry: The Synthesis and
(17) Nakamoto, K. IR and Raman Spectra of Inorganic and Coor-
dination Compounds, 5th ed.; Wiley: New York, 1997.
Reactions of Organic Compounds, Barton, D., Ollis, W. D., Eds.;
Pergamon: Exeter, U.K., 1979; Vol. 1, p 193.

2400 Organometallics, Vol. 22, No. 12, 2003
Pe´rez et al.
[Pd{[(MeO2CCdCCO2Me)2(η5-C5H3)CHdN(CH2)2NMe2]-
Fe(η5-C5H5)}Cl] (8a ) was not detected.
In the view of these findings and in order to elucidate
if compound 7b could be an intermediate species in the
formation of 8b, we also studied the reaction between
equimolar amounts of 7b and MeO2CCtCCO2Me in
refluxing CH2Cl2 under different refluxing periods (up
to 3 days). However, no evidence for the presence of 8b
in the reaction mixture was detected by NMR spectro-
copy. These findings indicate that the insertion of an
additional molecule of MeO2CCtCCO2Me into the σ-
(Pd-C) bond of 7b is unlikely to occur under these
experimental conditions, thus suggesting that complex
8b may be generated through a different pathway.
Ch a r a cter iza tion . All the compounds presented in
this work have been characterized by elemental analy-
ses (except complex 6b, which exhibits low stability in
the solid state), FAB+ mass spectrometry, and infrared
and one- and two-dimensional NMR spectroscopy, and
compounds 4a ,b, 5b, and 8b have also been character-
ized by X-ray diffraction.
In all cases the elemental analyses agreed with the
proposed formulas (see the Experimental Section). The
infrared spectra of all the compounds showed a sharp
and intense band in the range 1500-1650 cm-1, which
is ascribed to the stretching of the >CdN group.19 This
band appears at higher energies than for the five-
membered cyclopalladated complexes 2.13,14 For the ionic
derivatives, 4a ,b-6a ,b the typical bands of the [BF4]-
anion17 were also observed in the infrared spectra.
Proton and carbon-13 NMR spectroscopic data for all
the compounds is presented in the Experimental Sec-
tion, and in all cases the assignment of the signals has
been carried out with the aid of two-dimensional het-
eronuclear {1H-13C} experiments (HSQC and HMBC).
1H NMR spectra of all the compounds showed a group
of four signals of relative intensities 1/1/1/5 in the range
3.5-5.2 ppm, which is the typical pattern of 1,2-
disubstituted ferrocenes.20 The resonance of the imine
proton appeared as a singlet in the low-field region of
the spectra, and signals due to the protons of the two
(in 7) or four (in 4a ,b; 6a ,b, and 8b) R1 groups of the
inserted fragment were identified in the spectra. How-
F igu r e 1. ORTEP diagram of the cationic array of [Pd-
{[(PhCdCPh)2(η5-C5H3)CHdN(CH2)2NMe2]Fe(η5-C5H5)]-
[BF4]‚CH2Cl2 (4a ) together with the numbering scheme.
Hydrogen atoms have been omitted for clarity.
and was easily identified with the aid of two-dimen-
sional HSQC experiments, and in most of the cases the
signals due to the quaternary carbons of the inserted
fragment were also observed in the range 90-150 ppm
as low intense signals.
The resonances due to the carbon-13 nuclei of the -Et
or -OMe groups of the R1 substituents (in compounds
5a ,b -7a ,b and 8) were easily identified in the high-
field region of the spectra and provided additional
evidence of the incorporation of one (in 7a ,b) or two (in
5a ,b, 6a ,b, and 8b) molecules of the alkyne into the σ-
[Pd-C(sp2,ferrocene)] bond. The positions of the signals
were in good agreement with the results reported for
related palladacycles arising from mono or bis insertion
of the alkynes under study into the σ[Pd-C(sp2,
ferrocene)] (of 1) or the σ[Pd-C(sp2,aryl)] bond having
a similar arrangement of the R1 groups.8,12
Descr ip tion of th e Cr ysta l Str u ctu r es of [P d -
{[(P h CdCP h )2(η5-C5H 3)CH dN(CH 2)n NMe2]F e(η5-
C5H5)}][BF 4]‚CH2Cl2 (n ) 2 (4a ), 3 (4b)). The X-ray
crystal structures of these compounds consist of equi-
molar amounts of the heterobimetallic cations [Pd-
{[(P h CdCP h )2(η5-C5H 3)CH dN (CH 2)n N Me2]F e(η5-
C5H5)}]+ (n ) 2 (4a ), 3 (4b)), the [BF4]- anion, and
CH2Cl2.
Perspective drawings of the cationic arrays of 4a ,b
are depicted in Figures 1 and 2, respectively, and a
summary of the most relevant bond lengths and angles
is presented in Tables 2 and 3.
1
ever, the high-field regions of the H NMR spectra of
[Pd{[(EtCdCEt)2(η5-C5H3)CHdN(CH2)nNMe2]Fe(η5-
C5H5)}][BF4] (n ) 2 (5a ), 3 (5b)) were complex. In these
cases, the signals due to the protons of the -CH2-
moieties of the “dN(CH2)nNMe2” fragment overlapped
with those of the methylenic protons of the ethyl groups
belonging to the η3-butadienyl fragments, and the
assignment of these signals could only be achieved with
the aid of the two-dimensional {1H-13C} NMR experi-
ments.
13C{1H} NMR spectra of all the compounds were also
recorded (see the Experimental Section). The resonance
of the imine carbon appeared in the range 160-170 ppm
(19) (a) Onue, H.; Moritani, I. J . Organomet. Chem. 1972, 43, 431.
(b) Onue, H.; Nakagawa, K. Bull. Chem. Soc. J pn. 1970, 43, 3480. (c)
Albert, J .; Granell, J .; Sales, J .; Solans, X.; Font-Bard´ıa, M. Organo-
metallics 1986, 5, 2567. (d) Crespo, M.; Solans, X.; Font-Bard´ıa, M.
Organometallics 1995, 14, 355. (e) Wu, Y. L.; Ding, L.; Wang, H. Y.;
Liu, Y. H.; Yuan, H. Z.; Mao, X. A. J . Organomet. Chem. 1997, 535,
49.
(20) Gmelin Handuch der Anorganische Chemie. Eisen Organische-
Verbindunge. Ferrocen; Springer-Verlag: Heidelberg, Germany, 1977-
1986; Part A1-A8.
In the two cases, the palladium is four-coordinate,
since it is bound to the two nitrogen atoms of the
ferrocenylaldimine (N(1) and N(2)), to the terminal
carbon of the η3-butadienyl unit (C(37) in 4a and C(20)
in 4b), and to the middle point of the segment defined
by the atoms C(16) and C(23) in 4a or C(17)-C(18) in
4b (hereinafter referred to as ø and ø′) in a slightly

Cyclopalladated Compounds
Organometallics, Vol. 22, No. 12, 2003 2401
Ta ble 3. Selected Bon d Len gth s (in Å) a n d Bon d
An gles (in d eg) for [P d {[(P h CdCP h )2(η5-C5H3)-
CHdN(CH2)3NMe2]F e(η5-C5H5)}][BF 4]‚CH2Cl2 (4b)a
Selected Bond Lengths
Pd-N(1)
2.113(3)
2.030(4)
2.250(3)
2.552(4)
1.478(5)
1.491(5)
1.495(4)
1.518(6)
1.459(4)
1.498(6)
1.486(4)
2.041(21)
Pd-N(2)
2.141(3)
2.166(3)
2.090(3)
1.261(5)
1.422(4)
1.331(5)
1.487(5)
1.438(6)
1.526(6)
1.514(6)
1.464(5)
1.405(22)
Pd-C(20)
Pd-C(17)
Pd-C(19)
C(9)-C(17)
C(18)-C(19)
C(17)-C(21)
C(19)-C(33)
N(1)-C(12)
C(13)-C(14)
N(2)-C(15)
Fe-Cc
Pd-C(18)
Pd-øb
N(1)-C(11)
C(17)-C(18)
C(19)-C(20)
C(18)-C(27)
C(20)-C(39)
C(12)-C(13)
C(14)-N(2)
N(2)-C(16)
C-Cc
Selected Bond Angles
C(20)-Pd-N(2)
N(1)-Pd-øb
101.6(2) N(2)-Pd-N(1)
96.9(2) C(20)-Pd-øb
93.0(1) C(20)-Pd-C(18)
109.0(3) N(2)-C(14)-C(13)
89.9(1)
75.0(2)
66.6(2)
116.7(4)
111.0(3)
123.4(4)
128.5(3)
N(1)-Pd-C(17)
Pd-N(2)-C(14)
C(14)-C(13)-C(12) 115.4(4) C(13)-C(12)-N(1)
C(12)-N(1)-C(11)
C(11)-C(10)-C(9)
C(9)-C(17)-C(18)
116.8(4) N(1)-C(11)-C(10)
128.9(4) C(10)-C(9)-C(17)
120.5(3) C(17)-C(18)-C(19) 116.1(3)
C(18)-C(19)-C(20) 109.4(4) C(19)-C(20)-Pd
C(16)-N(2)-Pd
96.6(3)
114.9(3)
108.6(2) C(15)-N(2)-Pd
a
b
Standard deviation parameters are given in parentheses. ø′
represents the middle point of the segment defined by the atoms
C(17) and C(18). c Average value for the ferrocenyl moiety.
F igu r e 2. Molecular structure of the cationic array of [Pd-
{[(PhCdCPh)2(η5-C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)]-
[BF4]‚CH2Cl2 (4b) together with the numbering scheme.
Hydrogen atoms have been omitted for clarity.
lengths (2.116(7) and 2.239(7) Å, respectively (in 4a ),
or 2.166(3) and 2.250(4) Å (in 4b)). This arrangement,
also detected in [Pd{[(PhCdCPh)2(η5-C5H3)CHdNCH2-
Ph]Fe(η5-C5H5)}Cl],12a is different from those reported
for most nine-membered metallacycles arising from the
bis insertion of alkynes.11,12,23
Ta ble 2. Selected Bon d Len gth s (in Å) a n d Bon d
An gles (in d eg) for [P d {[(P h CdCP h )2(η5-C5H3)-
CHdN(CH2)2NMe2]F e(η5-C5H5)}][BF 4]‚CH2Cl2 (4a )a
Selected Bond Lengths
In 4a the C(30)-C(37) bond distance is clearly shorter
(1.343(9) Å) than that of the C(16)-C(23) double bond
(1.417(9) Å), and a similar trend is also found between
the C(19)-C(20) and C(17)-C(18) bond distances in 4b.
These differences can be attributed to the different type
of coordinations of the two >CdC< double bonds to the
palladium(II) atom (η1 and η2), respectively.
The cationic arrays of these compounds contain a
[5,9,5] (in 4a ) or a [5,9,6] (in 4b) tricyclic system formed
by the fusion of the substituted pentagonal ring of the
ferrocenyl moiety, a nine-membered metallacycle, and
a five- (in 4a ) or six-membered chelate ring (in 4b).
In the two compounds, the >CdN- functional group
is contained in the nine-membered metallacycles (en-
docyclic), and the >CdN- bond lengths (1.283(10) Å in
4a and 1.261(5) Å in 4b) do not differ significantly from
the values reported for cis-[M{[(η5-C5H4)CHdN(CH2)n-
Pd-N(1)
2.144(7)
2.040(7)
2.239(7)
2.614(7)
1.513(11)
1.501(10)
1.518(10)
1.454(10)
1.518(10)
1.449(12)
2.027(32)
Pd-N(2)
2.103(7)
2.116(7)
2.066(7)
1.283(10)
1.417(9)
1.343(9)
1.481(10)
1.428(10)
1.442(11)
1.474(13)
1.374(34)
Pd-C(37)
Pd-C(16)
Pd-C(30)
C(6)-C(16)
C(23)-C(30)
C(17)-C(16)
C(31)-C(30)
N(1)-C(12)
N(2)-C(14)
Fe-Cb
Pd-C(23)
Pd-øb
N(1)-C(11)
C(16)-C(23)
C(30)-C(37)
C(24)-C(23)
C(38)-C(37)
N(2)-C(15)
N(2)-C(13)
C-Cc
Selected Bond Angles
C(37)-Pd-N(2)
N(1)-Pd-øb
104.0(3)
119.6(3)
91.4(3)
84.1(3)
122.4(9)
129.2(7)
N(2)-Pd-N(1)
81.8(3)
74.2(3)
65.3(3)
130.9(6)
129.6(8)
121.7(7)
C(37)-Pd-øb
N(1)-Pd-C(16)
C(37)-Pd-C(16)
N(1)-C(11)-C(10)
C(10)-C(6)-C(16)
C(37)-Pd-C(23)
Pd-N(1)-C(11)
C(11)-C(10)-C(6)
C(6)-C(16)-C(23)
C(16)-C(23)-C(30) 118.1(7)
C(23)-C(30)-C(37) 104.0(6)
Pd-N(1)-C(12)
C(30)-C(37)-Pd
C(12)-C(13)-N(2)
C(11)-C(10)-C(9)
C(6)-C(16)-C(17)
99.1(5)
108.7(5)
106.5(6)
124.4(8)
114.0(10) C(13)-N(2)-Pd
121.5(8)
115.4(5)
(21) (a) For 4a , the least-squares equation of the plane defined by
the atoms N(1), N(2), C(37), and ø is (0.1841)XO + (0.8246)YO +
(0.5350)ZO ) 7.6792. Deviations from the plane (Å): N(1), -0.023;
N(2), 0.022; C(37), -0.025; ø, 0.025. (b) In 4b the least-squares equation
of the plane defined by the atoms N(1), N(2), C(20), and ø′ is (-0.1459)
XO + (0.9747)YO + (0.1693)ZO ) 1.2626. Deviations from the main
plane (Å): N(1), 0.229; N(2), -0.223; C(20), 0.273; ø′, -0.280.
(22) (a) Lo´pez, C.; Sales, J .; Solans, X.; Zquiak, R. J . Chem. Soc.,
Dalton Trans. 1992, 2321. (b) Bosque, R.; Lo´pez, C.; Sales, J .; Solans,
X. Font-Bard´ıa, M. J . Chem. Soc., Dalton Trans. 1994, 735. (c) Bosque,
R.; Font-Bard´ıa, M.; Lo´pez, C.; Silver, J .; Solans, X. J . Chem. Soc.,
Dalton Trans. 1994, 747. (d) Bosque, R.; Lo´pez, C.; Sales, J .; Solans,
X. J . Organomet. Chem. 1994, 483, 61. (e) Lo´pez, C.; Bosque, R.; Solans,
X.; Font-Bard´ıa, M. New J . Chem. 1998, 22, 977.
C(7)-C(6)-C(16)
C(17)-C(16)-C(23) 119.8(7)
C(30)-C(23)-C(24) 118.3(5)
C(31)-C(30)-C(37) 134.7(7)
C(16)-C(23)-C(24) 122.9(7)
C(23)-C(30)-C(31) 120.7(6)
C(30)-C(37)-C(38) 131.2(7)
C(38)-C(37)-Pd
129.2(5)
a
b
Standard deviation parameters are given in parentheses.
ø
represents the middle point of the segment defined by the atoms
C(16) and C(23). c Average value for the ferrocenyl moiety.
distorted square-planar environment.21 In both cases the
Pd-N and the Pd-C bond lengths are similar to those
found in five-membered cyclopalladated complexes.22
The double bond of the η3-butadienyl unit fragment
closest to the ferrocenyl unit is bound unsymmetrically
to the palladium(II), as reflected in the two Pd-C bond
(23) (a) Albinati, A.; Pregosin, P. S.; Ru¨edi, R. Helv. Chim. Acta,
1985, 68, 2064. (b) Maassarani, F.; Pfeffer, M.; Le Borgne, G.
Organometallics 1987, 6, 2029. (c) Maassarani, F.; Pfeffer, M.; van
Koten, G. Organometallics 1989, 8, 871. (d) Albert, J .; Granell, J .; Sales,
J .; Solans, X. J . Organomet. Chem. 1989, 379, 177.

2402 Organometallics, Vol. 22, No. 12, 2003
Pe´rez et al.
NMe2]Fe(η5-C5H5)}Cl2], (n ) 2, 3 and M ) Pd, Zn)14,24
or the cyclopalladated complexes [Pd{[(η5-C5H3)CHd
N(CH2)nNMe2]Fe(η5-C5H5)}Cl] (1.260(11) Å for n ) 2
(2a ) and 1.268(8) Å for n ) 3 (2b)).14,25
In 4a the phenyl substituents on the double bond
C(16)-C(23) are trans to each other and those on the
C(30)-C(37) are cis and a similar arrangement of the
phenyl rings is found for 4b. This is the most common
distribution of substituents found in related pallada-
cycles.11,12,23
The C(16)-C(23) bond (in 4a ) or the C(17)-C(18)
bond (in 4b) of the butadienyl unit is located above the
plane defined by the atoms (C(6)-C(10)) opposite to the
“Fe(η5-C5H5)” unit, and the phenyl bound to the C(16)
atom in 4a or to the C(17) atom in 4b is oriented toward
the iron(II). This type of arrangement is similar to those
found in [Pd{[(PhCdCPh)2(η3-C5H3)C(R2)dNR3]Fe(η5-
C5H5)}Cl] (R2 ) H, Me, Ph and R3 ) Ph, CH2Ph).2c,12a
In 4a , the five-membered chelate ring, formed by the
atoms Pd, N(1), N(2), C(12), and C(13), has an envelope-
like conformation,26 while the six-membered ring in 4b
exhibits a twist-boat conformation.27
F igu r e 3. Molecular structure of the cationic array of [Pd-
{[(EtCdCEt)2(η5-C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)]-
[BF4]‚CH2Cl2 (5b) together with the atom-labeling scheme.
Hydrogen atoms have been omitted for clarity.
In complex 4a the [BF4]- anion was found in disor-
dered positions, and in complex 4b the analysis of the
X-ray data suggests weak C-H‚‚‚F interactions28 in-
volving the sets of atoms C(4)-H(4)‚‚‚F(23), C(11)-
H(11)‚‚‚F(24), and C(15)-H(15A)‚‚‚F(22). In addition to
this finding, the separation between the centroid of the
C5H5 and the C(13)-H(13) bond (2.784 Å) of a neighbor-
ing cation indicate, according to the literature,29 the
existence of two weak C-H‚‚‚π(ring) interactions. A
similar feature is found between the phenyl ring, formed
by the atoms C(33)-C(38), and the C(41)-H(41) bond
(3.095 Å) of a close cation.
Descr ip tion of th e Cr ysta l Str u ctu r e of [P d {[(Et-
CdCEt)2(η5-C5H3)CHdN(CH2)3NMe2]F e(η5-C5H5)}]-
[BF 4]‚CH2Cl2 (5b). The X-ray crystal structure consists
of equimolar amounts of the cation [Pd{[(EtCdCEt)2-
(η5-C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)}]+ and the
[BF4]- anion. A perspective drawing of the cationic array
is depicted in Figure 3, and a summary of the most
relevant bond lengths and angles is presented in Table
4.
Ta ble 4. Selected Bon d Len gth s (in Å) a n d Bon d
An gles (in d eg) for [P d {[(EtCdCEt)2-
(η5-C5H3)CHdN(CH2)3NMe2]F e(η5-C5H5)}][BF 4] (5b)a
Selected Bond Lengths
Pd-N(1)
2.118(3)
2.012(4)
2.255(5)
2.579(5)
1.499(7)
1.401(7)
1.503(7)
1.320(8)
1.472(11)
1.520(11)
1.479(8)
2.033(13)
Pd-N(2)
2.150(5)
2.214(5)
1.980(5)
1.269(11)
1.525(7)
1.516(7)
1.503(8)
1.511(7)
1.518(12)
1.488(9)
1.482(8)
1.401(34)
Pd-C(26)
Pd-C(17)
Pd-C(23)
C(6)-C(17)
C(17)-C(20)
C(20)-C(23)
C(23)-C(26)
N(1)-C(12)
C(13)-C(14)
N(2)-C(14)
Fe-Cc
Pd-C(20)
Pd-øb
N(1)-C(11)
C(17)-C(18)
C(20)-C(21)
C(23)-C(24)
C(26)-C(27)
C(12)-C(13)
N(2)-C(15)
N(2)-C(16)
C-Cc
Selected Bond Angles
C(26)-Pd-N(2)
N(1)-Pd-øb
Pd-N(1)-C(11)
C(11)-C(10)-C(6)
C(6)-C(17)-C(20)
101.7(2) N(2)-Pd-N(1)
89.4(3)
74.7(2)
125.2(6)
127.4(5)
98.6(2) C(26)-Pd-øb
128.7(6) N(1)-C(11)-C(10)
129.5(5) C(10)-C(6)-C(17)
117.6(4) C(17)-C(20)-C(23) 119.9(4)
C(20)-C(23)-C(26) 108.4(4) Pd-N(2)-C(14)
108.3(4)
N(2)-C(14)-C(13)
C(13)-C(12)-N(1)
C(15)-N(2)-Pd
116.9(6) C(14)-C(13)-C(12) 114.5(6)
111.4(6) C(12)-N(1)-C(11)
114.4(4) C(16)-N(2)-C(14)
In the cation the palladium is bound to the two
nitrogen atoms (N(1) and N(2)), to the terminal carbon
of the η3-butadienyl unit (C(26)), and to the middle point
of the segment defined by the atoms C(17) and C(20)
(hereinafter referred to as ø′′). A slightly distorted
square planar environment is the result.30 The cation
117.0(5)
107.2(4)
a
b
Standard deviation parameters are given in parentheses. ø′′
represents the middle point of the segment defined by the atoms
C(17) and C(20). c Average value for the ferrocenyl moiety.
contains a [5,9,6] tricyclic system formed by the fusion
of the substituted pentagonal ring of the ferrocenyl
moiety, a nine-membered metallacycle, and a six-
membered chelate ring. The nine-membered metalla-
cycle contains the imine group (endocyclic).
(24) (a) Bosque, R.; Caubet, A.; Lo´pez, C.; Espinosa, E.; Molins, E.
J . Organomet. Chem. 1997, 544, 233. (b) Lo´pez, C.; Caubet, A.; Pe´rez,
S.; Bosque, R.; Solans, X.; Font-Bard´ıa, M. Polyhedron 2002, 21, 2361.
(25) (a) Lo´pez, C.; Pawełczyk, A.; Solans, X.; Font-Bard´ıa, M. Inorg.
Chem. Commun. 2003, 6, 451.
(26) The least-squares equation of the plane defined by the atoms
Pd, N(1), N(2), and C(12) in 4a is (0.0626)XO + (0.8145)YO + (0.5768)
YO ) 6.7269. Deviations from the main plane (Å): Pd, -0.065; N(1),
0.090; N(2), 0.054; C(12), -0.078.
(27) (a) Cremer, D.; Pople, J . A. J . Am. Chem. Soc. 1975, 97, 1354.
(b) Boeyens, J . C. A. J . Cryst. Mol. Struct. 1978, 8, 317.
(28) Le, H.; Knobler, C. B.; Hawthorne, M. F. Chem. Commun. 2000,
2485.
As described for 4b, also in this case the double bond
of the η3-butadienyl unit fragment closest to the ferro-
cenyl unit (C(17)-C(20)) is bound unsymmetrically to
the palladium(II), as reflected in the two Pd-C bond
lengths (2.214(5) and 2.255(5) Å, respectively), and the
Pd-C(26) bond length (2.012(4) Å) is shorter, if signifi-
cant, than the Pd-C(20) bond distance (2.030(4) Å) of
4b. The arrangement of the ethyl groups on the η3-
butadienyl fragment is similar to that found for 4b as
well as in [Pd{[(EtCdCEt)2(η5-C5H3)C(R2)dNR3]Fe(η5-
C5H5)}Cl].12a,e
(29) Nishio, N.; Hirota, M.; Umezakwo, Y. The C-H‚‚‚‚‚π Interaction;
Wiley-VCH: New York, 1988.
(30) The least-squares equation of the plane defined by the atoms
Pd, N(1), N(2), C(26), and the middle point of the segment C(17)-C(20)
(ø′′) in 5b is (0.9152)XO + (-0.3931)YO + (-0.0893)ZO ) 3.5800.
Deviations from the plane (Å): N(1), 0.390; N(2), -0.372; C(26), 0.456;
ø”, -0.483.

Cyclopalladated Compounds
Organometallics, Vol. 22, No. 12, 2003 2403
Ta ble 5. Selected Bon d Len gth s (in Å) a n d Bon d
An gles (in d eg) for [P d {[(MeO2CCdCCO2Me)2-
(η5-C5H3)CHdN(CH2)3NMe2]F e(η5-C5H5)}Cl] (8b)a
Selected Bond Lengths
Pd-C(17)
1.982(2)
2.177(2)
1.281(3)
1.451(3)
1.453(3)
1.468(3)
1.497(3)
1.510(3)
1.482(3)
2.037(11)
Pd-N(1)
2.027(2)
2.3025(6)
1.486(3)
1.513(4)
1.442(3)
1.346(3)
1.327(3)
1.498(3)
1.474(3)
1.405(30)
Pd-N(2)
Pd-Cl(1)
N(1)-C(11)
C(10)-C(11)
C(6)-C(10)
C(6)-C(26)
C(23)-C(20)
C(26)-C(27)
C(20)-C(21)
Fe-Cb
N(1)-C(12)
C(12)-C(13)
C(10)-C(9)
C(26)-C(23)
C(20)-C(17)
C(23)-C(24)
C(17)-C(18)
C-Cb
Selected Bond Angles
C(17)-Pd-N(1)
C(17)-Pd-Cl(1)
N(1)-C(11)-C(10) 132.0(2)
C(10)-C(6)-C(26) 123.3(2)
C(26)-C(23)-C(20) 120.7(2)
C(20)-C(17)-Pd
87.47(8) N(1)-Pd-N(2)
89.89(8)
94.01(6)
89.54(6) N(2)-Pd-Cl(1)
C(11)-C(10)-C(6) 133.5(2)
C(6)-C(26)-C(23) 122.0(2)
C(23)-C(20)-C(17) 118.3(2)
Figu r e 4. Molecular structure and atom-numbering scheme
for [Pd{[(MeO2CCdCCO2Me)2(η5-C5H3)CHdN(CH2)3NMe2]-
Fe(η5-C5H5)}Cl] (8b). Hydrogen atoms have been omitted
for clarity.
115.27(17) C(18)-C(17)-Pd
119.7(2)
a
Standard deviation parameters are given in parentheses.
Average value for the ferrocenyl moiety.
b
is similar to that found for 2 (1.260(11) Å in 2a and
1.287(5) Å in 2b )14,25 and those of related ferro-
cenylimines which fall in the range 1.25-1.31 Å.34
The most interesting feature of the crystal structure
of 8b is the relative arrangement of the four -CO2Me
groups; in this case the two pairs of -CO2Me groups on
the >CdC< bonds of the butadienyl fragment are in a
cis,cis arrangement, in contrast with the results ob-
tained for most of the palladacycles arising from the bis
insertion of the alkynes R1CtCR1, in which the four R1
substituents have a trans,cis orientation.12 In good
agreement with the conclusions reached from the mecha-
nistic studies of the bis insertion of alkynes into the σ-
[Pd-C(sp2,aryl)] bond,16 which suggested that although
in the monoinsertion product the two R1 groups are in
a cis arrangement, the cis f trans isomerization occurs
prior to the insertion of the second molecule of the
alkyne to produce the bis insertion complex.
The six-membered chelate ring, formed by the atoms
Pd, N(1), N(2), C(12), C(13), and C(14), has a boat
conformation.31 The differences observed in the bond
lengths of the two >CdC< bonds of the butadienyl unit
(C(17)-C(20) and C(23)-C(26)) can be ascribed to the
different modes of binding of these moieties (η2 and η1,
respectively).
Bond lengths and angles of the [BF4]- anion in 5b
agree with the values reported for other compounds
containing this ion,32 and the F(4)‚‚‚H(24) bond lengths
(2.4822 Å) suggests a weak C(24)-H(24)‚‚‚F(4) inter-
action.28
Descr ip tion of th e Cr ysta l Str u ctu r e of [P d -
{[(MeO2CCdCCO2Me)2(η5-C5H3)CHdN(CH2)2NMe2]-
F e(η5-C5H5)}Cl] (8b).The crystal structure of 8b to-
gether with the atom-numbering scheme is depicted in
Figure 4, and a selection of bond lengths and angles is
presented in Table 5.
For this crystal structure partial disorder affecting
the carbon atoms bound to the amine nitrogen was also
observed.35 The separation between the Cl and H(15A)
atom of a neighboring molecule (2.715 Å) is shorter than
the sum of the van der Waals radii of these atoms (Cl,
1.75 Å; H, 1.20 Å),36 suggesting a weak C(15)-H(15A)‚
The structure consists of [Pd{[(MeO2CCdCCO2Me)2-
(η5-C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)}Cl] separated
by van der Waals contacts. In each molecule the
palladium atom is four-coordinated, since it is bound
to a chlorine, the two nitrogen atoms of the ligand (N(1)
and N(2)), and the terminal carbon atom of the η1-
butadienyl unit (C(17)). A distorted-square-planar en-
vironment is the result.33 The Pd-Cl bond length
(2.3025(6) Å) is shorter than that found for 2a
(2.328(3) Å)25 or 2b (2.3143(9) Å).14
This complex contains a [5,9,6] tricyclic system which
is formed by fusion of the C5H3 ring, a nine-membered
palladacycle, and a six-membered chelate ring formed
by the coordination of the two nitrogen atoms of the
ligand (N(1) and N(2)) to the palladium(II).
37
‚‚Cl interaction.
For the four structures described above, bond lengths
and angles of the “(η5-C5H5)Fe(η5-C5H3)” fragment are
consistent with those found for most of the ferrocene
derivatives.32 The two pentagonal rings are planar and
nearly parallel (tilt angles 3.06, 7.95, 5.56, and 3.51°
(34) Lo´pez, C.; Bosque, R.; Solans, X.; Font-Bard´ıa, M. New J . Chem.
1996, 20, 1285.
(35) The three carbon atoms bound to the amine nitrogen, N(2),
showed a slight disorder, and two positions were identified for each of
these carbon atoms, which were identified as C(14) and C(14′), C(15)
and C(15′), and C(16) and C(16′).
The iminic group is contained in the metallacycle
(endocyclic), and the >CdN- bond length (1.281(3) Å)
(36) (a) Bondi, A. J . Phys. Chem. 1964, 68, 441. (b) Kitaigorodskii,
A. I. Molecular Crystals and Molecules; Academic Press: London, 1973.
(37) (a) Langfredi, M. A.; Tiripiccio, A.; Natile, G.; Gasparrini, F.;
Galli, B. Cryst. Struct. Commun. 1979, 6, 611. (b) Natile, G.; Gaspar-
rini, F.; Missiti, D. M.; Perego, G. J . Chem. Soc., Dalton Trans. 1977,
1747. (c) Katti, K. V.; Ge, Y. W.; Sing, P. R.; Date, S. V.; Barnes, C. L.
Organometallics 1994, 13, 541. (d) Codina, G.; Caubet, A.; Lo´pez, C.;
Moreno, V.; Molins, E. Helv. Chim. Acta 1999, 82, 1025. (e) Pe´rez, S.;
Bosque, R.; Lo´pez, C.; Solans, X.; Font-Bard´ıa, M. J . Organomet. Chem.
2001, 625, 67. (f) Lo´pez, C.; Bosque, R.; Solans, X.; Font-Bardia, M.
Polyhedron 2001, 20, 987.
(31) The least-squares equation of the plane defined by the atoms
Pd, N(2), C(12), and C(14) in 5b is (0.6824)XO + (-0.6786)YO +
(0.2715)ZO ) 3.0490. Deviations from this plane (Å): Pd, -0.124; N(2),
0.146; C(12), 0.179; C(14), -0.201; N(1), -0.646; C(13), -0.646.
(32) Allen, T. H.; Kennard, O. Chem. Des. Automat. News 1993, 8,
146.
(33) The least-squares equation of the plane defined by the atoms
N(1), N(2), Cl, and C(17) in 8b is (-0.5653)XO + (0.8243)YO + (0.0278)-
ZO ) 0.4539. Deviations from the plane (Å): N(1), -0.145; N(2),
+0.123; Cl, -0.121; C(17), 0.144 Å.

2404 Organometallics, Vol. 22, No. 12, 2003
Pe´rez et al.
for 4a ,b, 5b, and 8b, respectively), and they deviate by
ca. -24.46° (in 4a ), 30.8° (in 4b), 13.9° (in 5b), or 11.46°
(in 8b) from the ideal eclipsed conformation. In all cases,
the distance between the two metal atoms (4.5397 Å (in
4a ), 4.4954 Å (in 4b), 4.5648 Å (in 5b), and 5.2064 Å
(in 8b)) is clearly greater than the sum of the van der
Waals radii of these atoms,36 thus suggesting the
absence of any direct interaction between the Fe and
the Pd.
Attem p ts To Cla r ify th e Na tu r e of th e In ter m e-
d ia te Sp ecies 3. As a first approach to try to explain
why a nearly invariant amount of compounds 2 was
recovered after the treatment of these compounds with
Tl[BF4] (to give 3) and the subsequent reaction with
diphenylacetylene or hex-3-yne, we were prompted to
attempt the characterization of these intermediate
species 3.38 The infrared spectra of 3a ,b showed the
typical bands due to the [BF4]- anion,17 but their proton
NMR spectra were more complex than those initially
expected for the monomeric derivatives [Pd{[(η5-C5H3)-
CHdN(CH2)nNMe2]Fe(η5-C5H5)}(acetone)][BF4] (n ) 2,
3), which arise from 2 by the abstraction of the Cl-
ligand and the subsequent coordination of the solvent
(acetone). In fact, most of the signals observed in the
1H NMR spectra of 3 appeared duplicated and none of
(38) Characterization data for 3a are as follows. Anal. Calcd for
C33H44ClBF4Fe2N4OPd2‚1/2H2O: C, 40.93; H, 4.74; N, 5.78. Found: C,
40.6; H, 4.8; N, 5.6. MS (MALDI-TOF+) m/z 815 ([M - acetone -
BF4]+). IR: 1583 cm-1 (ν(>CdN-)); 1705 cm-1 (br, ν(>CO)). 1H NMR
(in acetone-d6): δ 4.35 and 4.33 (s, 10H, C5H5 and (C5H5)′); 4.46 and
4.50 (s, 2H, H3 and H3′); 4.65 and 4.70 (s, 2H, H4 and H4′); 4.87 and
4.90 (m, 2H, H5 and H5′); 8.03 and 8.07 (s, 2H, -CHdN- and (-CHd
N-)′); 3.40-3.80 (m, 4H, dNCH2- and (dNCH2-)′); 2.90-3.10 (m,
4H, (-CH2N-) and (-CH2N-)′); 2.63 (s, 3H, Me); 2.64 (s, 3H, Me);
2.70 (s, 3H, Me); 2.84 (s, 3H, Me). 1H NMR (in CDCl3): δ 4.34 and
4.38 (s, 10H, C5H5 and (C5H5)′); 4.42 and 4.47 (s, 2H, H3 and H3′); 4.85
(br, 2H, H4 and H4′); 5.23 (br, 2H, H5 and H5′); 8.04 and 8.06 (s, 2H,
-CHdN- and (-CHdN-)′); 3.35 and 3.50 (br m, 4H, dNCH2- and
(dNCH2-)′); 2.60 (s, 6H, 2 Me); 2.66 (s, 3H, Me); 2.76 (s, 3H, Me);
2.47 (s, 3H, Me (acetone)); the signals due to the proton of the -CH2N-
unit were partially masked by those due to the methyl groups. 13C-
{1H} NMR data (in CDCl3): δ 70.7 and 70.2 (C5H5) and (C5H5)′); 92.3
and 92.7 (C1 and C1′); 100.2 and 100.7 (C2 and C2′); 75.90 and 68.96
(C3 and C3′); 65.9 and 66.6 (C4 and C4′); 67.5 (C5); 173.1 and 174.0
(-CHdN- and (-CHdN-)′); 53.3 (br, dNCH2- and (dNCH2-)′);
63.60 and 63.89 -CH2N and (-CH2N)′); 48.0, 48.2 and 48.0 (Me and
Me′); 30.9 (Me (acetone)) and 206.9 (>C(O), acetone). Characterization
data for 3b are as follows. Anal. Calcd for C35H48ClBF4Fe2N4OPd2‚
H2O: C, 41.81; H, 5.01; N, 5.57. Found: C, 41.7; H, 5.1; N, 5.8. MS
F igu r e 5. Schematic view of (A) the structures proposed
for the cationic arrays of the intermediate species 3 and
(B) those of related dimeric cyclopalladated complexes
derived from the ligands 4-ClC6H4CHdNCH2(CH2)xNMe2
(x ) 1, 2) described recently, in which the mode of
coordination of the ligands is similar to that proposed for
compounds 3.
them were coincident with those of the corresponding
complex 2. A similar feature was observed in the 13C-
{1H} NMR spectra. These findings could be indicative
that the intermediate species 3 could have higher
nuclearity. Elemental analyses of these materials did
not differ substantially from those expected for the
polymeric complexes “{[Pd2{[(η5-C5H3)CHdN(CH2)n-
NMe2]Fe(η5-C5H5)}2Cl(acetone)][BF4]}x”. The MALDI-
TOF mass spectra showed a very intense signal at m/z
813 (for 3a ) and 842 (for 3b), which are consistent with
the values expected for the cations “[Pd2{[(η5-C5H3)CHd
N(CH2)nNMe2]Fe(η5-C5H5)}2Cl]+” (n ) 2, 3). Also, the
values of the molar conductivity of 10-3 M solutions of
3 in acetone (128 (3a ) and 140 Ω-1 cm2 mol-1 (3a )) were
in the upper range expected for a 1/1 electrolyte.39 In
the view of the characterization data available at this
point, we tentatively postulate for the intermediate
species 3 the dimeric structure [Pd2{[(η5-C5H3)CHd
N(CH2)nNMe2]Fe(η5-C5H5)}2Cl(acetone)][BF4] (A in
Figure 5). Quite recently, some authors have reported
the formation of the dimeric compounds [Pd{4-ClC6H4-
CHdN(CH2)nNMe2}X]2 (B in Figure 5) in the cyclo-
palladation of 4-ClC6H4CHdN(CH2)nNMe2 (n ) 2, 3).40
These compounds can be visualized as derived from the
parent ligands of 2, [(η5-C5H5)Fe{(η5-C5H4)CHdN(CH2)n-
(MALDI-TOF): m/z 842 ([M - acetone - BF4]+). IR: 1578 cm-1 1H
.
NMR (in acetone-d6): δ 4.34 (s, 10H, C5H5 and (C5H5)′); 4.41 and 4.42
(s, 2H, H3 and H3′); 4.61 and 4.65 (s, 2H, H4 and H4′); 5.08 (m, 2H, H5
and H5′); 8.18 and 8.32 (s, 2H, -CHdN- and (-CHdN-)′); 3.18, 3.54,
3.36, and 3.18 (m, 4H, dNCH2- and (dNCH2-)′); 1.81 and 1.98 (m,
4H, -CH2- and (-CH2-)′); 2.60 and 2.83 (m, 4H, -CH2N- and
(-CH2N-)′); 2.67, 2.04, 2.57, and 2.55 (4s, 12H, -NMe2 and (-NMe2)′).
1H NMR (in CDCl3): δ 4.33 and 4.40 (s, 10H, C5H5 and (C5H5)′), 4.45
and 4.30 (s, 2H, H3 and H3′); 4.42 and 4.56 (s, 2H, H4 and H4′); 5.30
(m, 2H, H5 and H5′); 8.07 and 8.11 (s, 2H, -CHdN- and (-CHdN-
)′); 3.42 (br m, 4H, dNCH2- and (dNCH2-)′); 1.18, 1.30, 1.52, and
1.62 (m, 4H, -CH2- and (-CH2-)′); 2.30 and 2.70 (m, 4H, -CH2N-
and (-CH2N-)′); 2.63 (s, 3H, Me); 2.67 (s, 6H, 2 Me); 2.72 (s, 3H, Me);
2.40 (s, 3H, Me (acetone)). 13C{1H} NMR data (in acetone-d6): δ 70.4
(C5H5)and (C5H5)′), 80.9 and 85.5 (C1 and C1′); 99.9 and 100.1 (C2 and
C2′); 74.0 and 68.8 (C3 and C3′); 67.4 and 74.7 (C4 and C4′); 70.4 (C5),
175.1 and 176.6 (-CHdN- and (-CHdN-)′); 57.3 and 57.7 (dNCH2-
and (dNCH2-)′); 26.4 and 26.5 (-CH2- and (-CH2-)′); 62.8 and 63.3
(-CH2-N and (-CH2-N)′); 48.1 and 48.9 (Me and Me′). 13C{1H} NMR
(in CDCl3): δ 71.3 and 71.6 (C5H5 and (C5H5)′), 86.4 and 86.7 (C1 and
C1′); 96.8 and 104.1 (C2 and C2′); 77.5 (C3 and C3′); 67.6, 67.8, 69.4, and
69.6 (C4, C4′, C5, and C5′), 175.7 (br, -CHdN- and (-CHdN-)′); 63.1
and 63.8 (dNCH2- and (dNCH2-)′); 24.8 and 26.5 (-CH2- and
(-CH2-)′); 57.9 and 59.8 (-CH2N and (-CH2N)′), 48.7, 49.2 (br) and
48.7 (Me and Me′; 29.9 (Me (acetone)); in this case the signal due to
the carbon-13 nuclei of the >CO group of the acetone was not observed.
For the two compounds the 1H-1H-NOESY experiments (in CDCl3 at
20 °C) suggested that the halves of the cations of these compounds
underwent a dynamic process in solution.
(39) Geary, W. J . Coord. Chem. Rev. 1971, 7, 87.
(40) Go´mez, M.; Granell, J .; Martinez, M. Inorg. Chem. Commun.
2002, 5, 67.

Cyclopalladated Compounds
Organometallics, Vol. 22, No. 12, 2003 2405
Ta ble 6. Selected Bon d Len gth s (in Å) a n d Bon d
An gles (in d eg) a r ou n d th e P a lla d iu m Atom in
NMe2}], by replacement of the ferrocenyl group by the
4-ClC6H4 moiety.
[P d {[(η5-C5H3)CHdN(CH2)n NMe2]F e(η5-C5H5)}Cl] (n
As mentioned above, in the insertion of the alkynes
into the σ(Pd-C) bond of cyclopalladated complexes the
first step involves the coordination of the alkyne in the
cis arrangement to the metalated carbon.16 For the
structures proposed for 3, the halves of the cations
(hereinafter referred to as I and II) are not identical.
In one of them (fragment I) the palladium(II) is bound
to an acetone molecule, while in the other half of the
cation (II) a chlorine is in a position cis to the metalated
carbon. Since it is widely accepted that the Pd-O-
(acetone) bond is more labile than the Pd-Cl bond,41
the coordination of the alkyne is expected to be more
likely to occur in fragment I than in the other half of
the cation, where the palladium(II) is bound to a
chlorine ligand. The results presented above revealed
that compounds 2 (in which the chlorine and the
metalated carbon are also in adjacent positions) did not
react with the less reactive alkynes used in this work
(diphenylacetylene and hex-3-yne).18 Thus in these
cases, only one fragment of the cation (half I) will allow
the coordination of these alkynes and their subsequent
insertion to produce the ionic compounds 4 and 5. In
contrast with these results, when the reaction was
carried out with Me2OCCtCCO2Me, which is more
reactive, the halves of the molecule would be involved
in the process: fragment I could lead to compounds 6
(which have a similar backbone to those of 4 and 5),
while the other half would produce the neutral deriva-
tives [Pd{[(MeO2CCdCCO2Me)(η5-C5H3)CHdN(CH2)n-
NMe2]Fe(η5-C5H5)}Cl] (n ) 2 (7a ), 3 (7b)), which are
also formed in the reaction of compounds 2 with Me2-
OCCtCCO2Me in the absence of Tl(I) salts.
) 2 (2a ),25 3 (2b)13
)
a
2a
2b
Pd-Cl
2.328(3)
1.963(7)
1.960(6)
2.196(4)
2.3143(9)
1.964(3)
2.052(3)
2.205(3)
Pd-C
Pd-N(1)
Pd-N(2)
C-Pd-Cl
96.1(2)
100.40(14)
80.5(3)
91.27(10)
92.86(8)
81.02(12)
94.56(11)
Cl-Pd-N(2)
N(1)-Pd-C
N(2)-Pd-N(1)
82.59(18)
a
N(1) and N(2) represent the imine and amine nitrogen atoms,
respectively, and C indicates the metalated carbon atom. Standard
deviation parameters are given in parentheses.
in the reactivity of compounds 1-3 could be related to
the different labilities of the bonds between the palla-
dium(II) and the ligands on a arrangement cis to the
metalated carbon. On the other hand, the variations
detected in the σ(M-ligand) bond lengths within a
family of related complexes has been frequently used
to rationalize the different reactivities of these com-
pounds toward a given ligand. Commonly, for a given
ligand (L), larger σ(M-ligand) bond distances are
related to the greater lability of the bond. However, the
comparison of structural data of compounds 2a ,b pre-
sented in Table 6 show that, despite the fact that the
results presented in this work provide conclusive evi-
dence of the higher reactivity of complex 2b versus the
alkyne MeO2CCtCCO2Me, when compared with that
of 2a , the Pd-Cl bond length is (2.3143(9) Å) shorter,
if significant, than in 2a (2.328(3) Å25), and in the two
cases the Pd-C bond lengths involved in the insertion
process are practically identical: (1.963(7) Å in 2a and
1.964(3) Å in 2b); thus, these findings suggest that other
more subtle factors, i.e. the accessibility of the alkyne
to the metal center, the steric effects induced by the
chelate ring, or its flexibility, may also play an impor-
tant role in these sorts of processes.
In addition, the results obtained from these studies
indicate that the nature of the substituents, R1, on the
alkyne plays a crucial role in the determining the size
of the metallacycle formed by the insertion. For the
alkynes holding electron-donor groups the formation of
the ionic compounds [Pd{[(R1CdCR1)2(η5-C5H3)CHd
N(CH2)nNMe2]Fe(η5-C5H5)}][BF4] (n ) 2, 3 and R1 ) Ph,
Et) through a bis insertion process is strongly preferred,
while if the reaction was performed under identical
conditions but using MeO2CCtCCO2Me, which contains
an electron-withdrawing substituent, in addition to the
compounds [Pd{[(MeO2CCdCCO2Me)2(η5-C5H3)CHd
N(CH2)nNMe2]Fe(η5-C5H5)}][BF4] (6), the monoinsertion
derivatives [Pd{[(MeO2CCdCCO2Me)(η5-C5H3)CHdN-
(CH2)nNMe2]Fe(η5-C5H5)}Cl] (7; n ) 2, 3) were also
obtained.
Con clu sion s
The results reported here reveal that the compounds
[Pd{[(η5-C5H3)CHdN(CH2)nNMe2]Fe(η5-C5H5)}Cl] (n )
2 (2a ), 3 (2b)) are less prone to undergo the bis insertion
of diphenylacetylene or hex-3-yne than the correspond-
ing dimeric derivatives [Pd{[(η5-C5H3)C(R2)dNR3]Fe(η5-
C5H5)}(µ-Cl)]2 (1).12 This finding may be due to several
causes, among which the mode of binding of the ligand
and/or the strength of the Pd-Cl bonds appear to be
the most relevant. On the other hand, since the inter-
mediate species formed by the addition of thallium(I)
salts (3a ,b) are more reactive than the starting materi-
als 2a ,b, the proclivity of the three sorts of cyclopalla-
dated derivatives to undergo insertion of the alkynes
increases according to the sequence: 2a < 2b < 3a <
3b < 1. This trend shows that tiny changes in the
[C(sp2,ferrocene),N,N′]- terdentate ligand, such as the
incorporation of a -CH2- moiety in the chelate ring,
play also a crucial role in the tuning of the reactivity of
these sorts of compounds with the alkynes studied. In
addition, since for palladacycles containing [C(sp2,
phenyl),N]- bidentate ligands it has been demonstrated
that the first step of the insertion process requires the
binding of the alkyne to the metal in the position
adjacent to the σ(Pd-C) bond,16 the differences observed
The study of the reactions of compounds 2 with the
alkynes R1CtCR1 has allowed the obtainment of a wide
variety of neutral and ionic palladacycles containing
seven- or nine-membered rings, and since it is well-
known that the applications of cyclopalladated com-
plexes as precursors for organic or organometallic
synthesis are commonly based on their reactions with
alkynes, followed by depalladation processes, com-
pounds 3-8 presented here appear to be excellent
(41) Comprehensive Organometallic Chemistry: The Synthesis, Re-
actions and Structure of Organometallic Compounds; Wilkinson, G.,
Stone, F. G. A., Abel, E. W., Eds.; Pergamon Press: New York, 1982;
Vol. 6, p 236.

2406 Organometallics, Vol. 22, No. 12, 2003
Pe´rez et al.
H5); 8.25 (s, 1H, -CHdN-); 3.54 and 3.95 (m, 2H, dNCH2-),
2.76 and 3.08 (m, 2H, -CH2N); 2.55 (s, 3H, Me); 2.40 (s, 3H,
Me); 6.35-7.60 (m, 20 H, Ph); 5.12 (s, 2H, CH2Cl2). 13C{1H}
NMR data (selected data):44 δ 72.8 (C5H5); 88.2 (C1); 70.8 (C2);
77.1 (C3); 74.5 (C4); 74.1 (C5); 166.3 (-CHdN-); 66.5 (dNCH2-
); 55.9 (-CH2N-), 50.6 (Me) and 49.4 (Me); 94.76, 114.0, 144.6,
and 145.9 (CR, Câ, Cδ, and Cγ).
substrates for clarifying the influence of the size of the
chelate ring upon the nature of the final depalladation
products. Studies in this field are currently under way.
Exp er im en ta l Section
Gen er a l Com m en ts. The alkynes R1CtCR1 (with R1 ) Ph,
Et, CO2Me) were obtained from commercial sources and used
as received. The palladium(II) complexes [Pd{[(η5-C5H3)CHd
N(CH2)nNMe2]Fe(η5-C5H5)}Cl] (n ) 2 (2a ), 3 (2b)) were pre-
pared as described previously.13,14 Some of the preparations
described below require the use of hazardous materials such
as Tl[BF4], which should be handled with caution. Tl[BF4] was
prepared as reported previously.42 The solvents used were
dried and distilled according to the procedures described in
the literature.43
P r epar ation of [P d{[(P h CdCP h )2(η5-C5H3)CHdN(CH2)3-
NMe2]F e(η5-C5H5)][BF 4]‚CH2Cl2 (4b). An acetone solution
(20 mL) containing 210 mg (4.58 × 10-4 mol) of 2b was treated
with Tl[BF4] (199 mg, 6.83 × 10-4 mol), and the resulting
mixture was stirred for 3 h at room temperature. The solid
formed during this period, TlCl, was removed by filtration, and
the filtrate was concentrated to dryness on a rotary evaporator.
The residue was then treated with CH2Cl2 (ca. 20 mL) and
filtered out to remove the unreacted Tl[BF4]. Then PhCtCPh
(163 mg, 9.14 × 10-4 mol) was added to the filtrate and the
reaction mixture was refluxed for 2 h. The resulting solution
was filtered out, and the filtrate was concentrated to dryness
on a rotary evaporator. The residue was then passed through
a SiO2 column (4.5 cm × 2 cm). Elution with CH2Cl2 produced
the release of a red band containing the unreacted 2b (54 mg).
Once this band was collected, a CH2Cl2/MeOH (100/1) mixture
eluted an orange band which gave, after concentration to
dryness, compound 4b (99 mg, 23%). Characterization data
are as follows. Anal. Calcd for C44H41N2BF4FePd‚3/4CH2Cl2: C,
59.03, H, 4.79; N, 3.08. Found: C, 59.0; H, 4.8; N, 3.2. MS
(FAB+): m/z 759 ([M - BF4]+). IR: 1637 cm-1 (ν(>CdN-)).
1H NMR:43 δ 4.31 (s, 5H, C5H5); 4.52 (s, 1H, H3); 4.74 (s, 1H,
H4), 4.77 (s, 1H, H5); 7.94 (s, 1H, -CHdN-); 3.62 and 3.70
(m, 2H, dNCH2-); 2.08 and 2.18 (m, 2H, -CH2-); 2.69 and
3.20 (m, 2H, -CH2N-); 2.56 (s, 3H, Me); 2.41 (s, 3H, Me);
6.40-7.35 (m, 20H, aromatic); 5.12 (s, 2H, CH2Cl2). 13C{1H}
NMR selected data:43 δ 72.1 (C5H5); 88.3 (C1); 71.9 (C2); 76.6
(C3); 72.9 (C4); 74.1 (C5); 168.4 (-CHdN-); 54.7 (dN-CH2-);
23.5 (-CH2-); 60.4 (-CH2-N); 52.6 (Me); 47.6 (Me).
Elemental analyses were carried out at the Serveis Cien-
tifico-Te`cnics (Universitat de Barcelona), at the Serveis de
Recursos Cientifics i Te`cnics (Universitat Rovira Virgili,
Tarragona, Spain), or at the Institut de Quimica Bio-Orga`nica,
(CSIC, Barcelona, Spain). Infrared spectra were obtained with
1
a Nicolet-500FTIR instrument using KBr pellets. Routine H
NMR spectra were recorded at ca. 20 °C on a Gemini-200 MHz
instrument using CDCl3 (99.9%) as solvent and SiMe4 as
internal standard, except for compounds 3, for which the
solvent used for the NMR studies was acetone-d6 (99.9%).
High-resolution 1H NMR and the two-dimensional {1H-1H}
NOESY and the {1H-13C} heteronuclear correlation experi-
ments (HMBC and HSQC) were recorded with either a Varian
VRX-500 or a Bruker Advance DMX-500 instrument. 13C{1H}
NMR spectra were obtained with a Mercury-400 instrument.
Mass spectra (MALDI-TOF+ for compounds 3 and FAB+ for
the remaining complexes) were registered at the Servei de
Espectrometr´ıa de Masses (Universitat de Barcelona) with
VOYAGER-DE-RP and VG-Quatro instruments, respectively.
For the FAB+ spectra, nitrobenzyl alcohol (NBA) was used as
matrix; for MALDI-TOF+, 2-hydroxybenzoic acid (DHB) was
P r ep a r a tion
of
[P d {[(EtCdCEt)2(η5-C5H3)CHdN-
(CH2)2NMe2]F e(η5-C5H5)][BF 4]‚CH2Cl2 (5a ). This compound
was prepared by following the same procedure as described
for 4a , but using 150 mg (3.5 × 10-4 mol) of 2a , 154 mg (5.3 ×
10-4 mol) of Tl[BF4], and hex-3-yne (0.85 mL, 7.5 × 10-4 mol)
as starting materials. In this case the reaction mixture was
refluxed for 6 h, and the workup of the column led to unreacted
3 (60 mg) and a gummy material which was dried under
reduced pressure for 5 days, giving the bright orange solid 5a
(73 mg, 25%). Characterization data for 5a are as follows. Anal.
Calcd for C27H39BF4FeN2Pd‚CH2Cl2: C, 50.71; H, 4.50; N, 4.25.
Found: C, 50.62; H, 4.37; N, 4.14. MS (FAB+ ): m/z 553 ([M
- BF4]+). IR: 1632 cm-1 (ν(>CdN-)).1H NMR:44 δ 4.34 (s, 5H,
C5H5); 4.60 (s, 2H, H3 and H4); 4.77 (s, 1H, H5); 8.32 (s, 1H,
-CHdN-); 3.60-3.68 (br m, 2H, dNCH2-); 2.80-2.98 (br m,
2H, -CH2N); 2.85 (s, 3H, Me); 2.69 (s, 3H, Me); 1.50, 2.15,
2.77, and 2.62 (br m, 8H, 4 -CH2- (Et)) and four triplets at
1.54, 1.09, 0.94, and 0.89 due to the protons of the -CH3
fragment of the four ethyl groups. 13C{1H} NMR data:44 δ 70.2
(C5H5); 86.9 (C1); 70.1 (C2); 70.8 and 71.2 (C3 and C4); 72.4 (C5);
165.7 (-CHdN-); 69.3 (dNCH2-); 64.7 (-CH2N); 49.1 (Me)
and 50.4 (Me); 20.1, 21.4, 24.3, 34.2 (-CH2 (Et)); 11.39, 13.7,
14.4, and 17.1 (-CH3 (Et)); and four signals at 103.7, 110.3,
139.8, and 141.0 due to the four quaternary carbon nuclei (CR,
Câ, Cδ, and Cγ, respectively) of the inserted η3-butadienyl
moiety.
used as matrix. Molar conductivity measurements of 10-3
M
solutions of 3 in acetone were determined at 20 °C with a
CRISON conductivity meter.
P r epar ation of [P d{[(P h CdCP h )2(η5-C5H3)CHdN(CH2)2-
NMe2]F e(η5-C5H5)}][BF 4]‚CH2Cl2 (4a ). A 114 mg (3.9 × 10-4
mol) amount of Tl[BF4] was added to a solution formed by 111
mg (2.6 × 10-4 mol) of 2a and 20 mL of acetone. The reaction
mixture was stirred at room temperature (ca. 20 °C) for 2 h.
After this period the undissolved materials were removed by
filtration and discarded. The red-brown filtrate was concen-
trated to dryness on a rotary evaporator, and the gummy
residue obtained was then treated with 15 mL of CH2Cl2 and
filtered out. Then, diphenylacetylene (93 mg, 5.2 × 10-4 mol)
was added to the filtrate and the reaction mixture was refluxed
for 2 h. After this period the resulting solution was concen-
trated to ca. 5 mL on a rotary evaporator and was passed
through a small SiO2 chromatography column (4.5 cm × 2 cm).
Elution with CH2Cl2 produced the release of a red band, which
led after concentration to dryness to small amounts (40 mg)
of the starting material. The subsequent elution with a CH2-
Cl2/MeOH (100/1) solution produced the release of an orange
band, which was collected and concentrated to dryness on a
rotary evaporator, giving 4a as an orange-brown solid (yield
82 mg, 34%). Characterization data are as follows. Anal. Calcd
for C43H39BF4FeN2Pd‚CH2Cl2: C, 57.58; H, 4.54; N, 2.95.
Found: C, 58.08; H, 4.65; N, 3.01. MS (FAB+): m/z 758.8 ([M]
P r ep a r a tion of [P d {[(EtCdCEt)2(η5-C5H3)CHdN(CH2)3-
NMe2]F e(η5-C5H5)}][BF 4]‚CH2Cl2 (5b). This compound was
prepared according to the procedure described for 5a , but using
193 mg (4.39 × 10-4 mol) of 2b, 192 mg (6.59 × 10-4 mol) of
Tl[BF4], and 0.100 mL (8.80 × 10-4 mol) of hex-3-yne, and in
this case the reaction mixture was refluxed for 2 h. Elution
with CH2Cl2 produced compound 2b, and subsequent elution
with CH2Cl2/MeOH (100/1) produced the release of an orange
band that led after concentration to a gummy red residue,
1
- Cl - BF4)}+. IR: 1637 cm-1 (ν(>CdN-)). H NMR:44 δ 4.33
(s, 5H, C5H5); 4.71 (s, 1H, H3); 4.76 (s, 1H, H4); 4.80 (s, 1H,
(42) Kowala, C.; Swan, J . M. Aust. J . Chem. 1966, 19, 547.
(43) Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory
Chemicals, 3rd ed.; Pergamon Press: London, 1998.
(44) Labeling of the atoms corresponds to those shown in the
schemes and charts.

Cyclopalladated Compounds
Organometallics, Vol. 22, No. 12, 2003 2407
which was dried under vacuum for 3 days, giving 5b as a
bright orange solid (yield 53 mg, 18%). Good-quality crystals
of 5b suitable for X-ray study were isolated by slow evapora-
tion of a CH2Cl2 solution of the solid sample layered with
n-hexane. Characterization data for 5b are as follows. Anal.
Calcd for C28H41BF4FeN2Pd‚1/2H2O: C, 50.67; H, 6.37; N, 4.22.
Found: C, 50.5; H, 6.7; N, 4.2. MS (FAB+): m/z 567 ([M -
BF4]+). IR: 1637 cm-1 (ν(>CdN-)).1H NMR:44 δ 4.38 (s, 5H,
C5H5); 4.65 (s, 2H, H3 and H4); 4.87 (s, 1H, H5); 8.39 (s, 1H,
-CHdN-), 3.84 (m, 2H, dNCH2-); 2.75-3.02 (m, 10H, 2Me,
-CH2N and 1 -CH2- (Et)); 2.14-2.24 (m, 6H, -CH2- and 2
-CH2- (Et)); 1.50 (m, 2H, -CH2- (Et)); and four triplets at
0.94, 0.97, 1.13, and 1.62 due to the protons of the -CH3
fragment of the four ethyl groups. 13C{1H} NMR:44,45 δ 71.5
(C5H5); 87.9 (C1); 70.4 and 71.6 (C3 and C4); 73.2 (C5); 168.9
(-CHdN-); 55.3 (dNCH2- and Me); 60.8 (-CH2N); 36.2, 24.3,
and 22.3 (-CH2- and CH2 (Et)); 12.9, 13.7, 15.2, and 19.2
(-CH3 (Et)); and four signals at 97.9, 116.1, 142.8, and 143.1
due to the four quaternary carbon nuclei (CR, Câ, Cδ, and Cγ,
respectively, of the inserted η3-butadienyl moiety).
CCO2Me)2(η5-C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)}Cl] (8b) was
isolated from the second yellow band released from the column.
Once this band was collected, the elution with CH2Cl2/MeOH
(100/1.5) produced the release of a deep purple band containing
compound 6b, which was isolated as a solid by concentration
to dryness on a rotary evaporator (yield 40 mg, 8%). Charac-
terization data for 6b are as follows. MS (FAB+): m/z 688 ([M
- (BF4)]+). IR: 1635 cm-1 (ν(>CdN-)) and 1728 cm-1 (br,
ν(>COO)). 1H NMR:44 δ 4.52 (s, 5H, C5H5); 4.94 (s, 1H, H3);
5.09 (s, 1H, H4); 5.16 (s, 1H, H5); 8.56 (s, 1H, -CHdN-); 3.67
and 3.94 (m, 2H, dNCH2-); 2.20 and 2.54 (m, 2H, -CH2-);
2.88 and 3.12 (m, 2H, -CH2N-); 3.05 (s, 3H, Me); 2.82 (s, 3H,
Me); and four singlets at 3.60, 3.72, 3.87, and 3.96 (s, 12H, 4
OMe). 13C{1H} NMR:44 δ 73.2 (C5H5); 77.7 (C1); 70.5 (C2); 75.9
(C3); 74.6 (C4); 76.9 (C5); 171.9 (-CHdN-); 54.7 (dNCH2-);
23.7 (-CH2-); 61.0 (-CH2N-); 54.4 (Me); 50.2 (Me); 52.7, 53.1,
53.6, and 54.1 (4 OMe); 158.8, 163.1, 166.6, and 168.2 (4
-COO); and three additional signals at 118.9 (CR), 135.1 (Câ
and Cδ), 149.7 (Cγ) of the inserted η3-butadienyl moiety.
Characterization data for 8b are as follows. Anal. Calcd for
P r ep a r a t ion of [P d {[(MeO2CCdCCO2Me)2(η5-C5H 3)-
CHdN(CH2)2NMe2]F e(η5-C5H5)}][BF 4] (6a ). This compound
was prepared as described above for 4a but using 2a (140 mg,
3.3 × 10-4 mol), Tl[BF4] (143 mg, 4.9 × 10-4 mol), and MeO2-
CCtCCO2Me (0.81 mL, 6.6 × 10-4 mol). In this case once the
refluxing period finished, the solution was filtered out and the
filtrate was concentrated to ca. 10 mL on a rotary evaporator.
Addition of n-hexane to the resulting solution produced the
precipitation of 6a as a red-purple solid, which was filtered
out, washed with small portions (ca. 2 mL) of n-hexane, air-
dried, and then dried under vacuum (yield 101 mg, 25%). The
slow evaporation of the yellow filtrate produced compound 7a
(yield 52 mg). Characterization data for 6a are as follows. Anal.
Calcd for C28H33BF4FeN2O8Pd‚1/2CH2Cl2: C, 41.13; H, 4.02; N,
3.49. Found: C, 40.92; H, 4.11; N, 3.49. MS (FAB+): m/z 673
([M - (BF4)]+). IR: 1635 cm-1 (ν(>CdN-)); 1710 and 1692
C
28H33FeClN2O8Pd‚CH2Cl2: C, 43.10; H, 4.36 and N, 3.50.
Found: C, 43.7; H, 4.6; N, 3.5. MS (FAB+): m/z 688 ([M -
Cl]+). IR: 1624 cm-1 (ν(>CdN-)); 1734, 1724, 1714, and 1698
cm-1 (ν(>COO)). H NMR:44 δ 4.24 (s, 5H, C5H5); 4.57 (d, 1H,
1
H3, 3J (H-H) ) 2.5 Hz); 4.61 (t, 1H, H4, 3J (H-H) ) 2.5 Hz);
4.80 (d, 1H, H5, J (H-H) ) 2.5 Hz); 7.96 (s, 1H, -CHdN-);
3
3.69 and 4.70 (m, 2H, dNCH2-); 1.77 and 2.10 (m, 2H, -CH2-
); 2.67 and 2.80 (m, 2H, -CH2N-); 2.76 (s, 3H, Me); 2.45 (s,
3H, Me); and four singlets at 3.69, 3.75, 3.77, and 4.07 (s, 12H,
4 OMe). 13C{1H} NMR:44 δ 71.5 (C5H5); 80.4 (C1); 71.7 (C2);
77.8 (C3); 72.7 (C4); 76.7 (C5); 169.2 (-CHdN-); 62.1 (dNCH2-
); 26.3 (-CH2-); 58.3 (-CH2N-); 49.5 (Me); 47.8 (Me); 51.5,
52.1, 52.5, and 52.6 (4 -OMe); 163.2, 165.5, 169.0, and 171.8
(4 -COO); and four additional signals at 125.4, 138.3, 139.9,
and 158.8, assigned to CR, Câ, Cδ, and Cγ of the inserted η3-
butadienyl moiety.
1
cm-1 ((br), ν(>COO)). H NMR:44 δ 4.47 (s, 5H, C5H5); 4.90 (s,
P r ep a r a tion of [P d{[(MeO2CCdCCO2Me)(η5-C5H3)CHd
N(CH2)n NMe2]F e(η5-C5H5)}Cl] (n ) 2 (7a ), 3 (7b)). Although
these compounds were also isolated as byproducts during the
synthesis of 6a or 6b, the procedure described here allows their
isolation in a higher yield. The corresponding complex (2a ,b;
4.08 × 10-4 mol) was dissolved in CH2Cl2 (ca. 5 mL), and then
an equimolar amount of MeO2CCtCCO2Me (0.050 mL, 4.08
× 10-4 mol) was added. The reaction mixture was refluxed for
21 h (for 7a ) or for 6 h (for 7b) and then filtered out. The
undissolved materials were discarded, and the filtrate was
concentrated to dryness on a rotary evaporator. The residue
was then dissolved in the minimum amount of CH2Cl2 and
passed through a SiO2 column (4 cm × 2 cm) using a CH2Cl2/
MeOH (100/1) mixture as eluant. The yellow band that was
released was collected and concentrated to dryness on a rotary
evaporator (yield 118 mg (70.6%) for 7a and 98 mg (42%) for
7b). Characterization data for 7a are as follows. Anal. Calcd
for C21H25FeClN2O4Pd‚CH2Cl2: C, 40.52; H, 4.17; N, 4.30.
Found: C, 40.9; H, 4.2; N, 4.4. MS (FAB+): m/z 531 ([M -
Cl]+). IR: 1646 cm-1 (ν(>CdN-)) and 1716 cm-1 (ν(>COO)).1H
NMR:44 δ 4.20 (s, 5H, C5H5); 4.54 (t, 2H, H3); 4.58 (t, 1H, H4,
1H, H3); 4.96 (s, 1H, H4); 5.22 (s, 1H, H5); 8.05 (s, 1H, -CHd
N-); 3.94 and 4.05 (m, 2H, dNCH2-); 2.80 and 3.20 (m, 2H,
-CH2N); 3.02 (s, 3H, Me); 2.99 (s, 3H, Me); four singlets at
3.61, 3.76, 3.90, and 3.97 (12H, 4 OMe) and 5.12 (s, 1H, CH2-
Cl2). 13C{1H} NMR:44,45 δ 71.8 (C5H5); 88.1 (C1); 75.1 (C3); 74.6
(C4); 77.2 (C5); 168.1 (-CHdN-); 65.7 (dNCH2-); 57.2
(-CH2N-); 48.6 (Me); 50.4 (Me); 52.8, 52.6, 51.8, and 51.5 (4
OMe); 159.2, 164.7, 167.2, and 169.5 (4 -COO); and four
additional signals at 112.1, 136.2, 137.0, and 150.0 assigned
to CR, Câ, Cδ, and Cγ of the inserted η3-butadienyl moiety.
P r ep a r a t ion of [P d {[(MeO2CCdCCO2Me)2(η5-C5H 3)-
CHdN(CH2)3NMe2]F e(η5-C5H5)}][BF 4] (6b) a n d [P d {[(Me-
O2CCdCCO2Me)2(η5-C5H3)CHdN(CH2)3NMe2]Fe(η5-C5H5)}-
Cl] (8b). Compound 2b (269 mg, 6.13 × 10-4 mol) was
dissolved in 20 mL of acetone, and then 266 mg (9.13 × 10-4
mol) of Tl[BF4] was added. The reaction mixture was stirred
at room temperature for 2 h and then filtered out to remove
the thallium(I) chloride formed. The filtrate was concentrated
to dryness on a rotary evaporator, and the residue was treated
with CH2Cl2. The undissolved materials (TlCl and the unre-
acted Tl[BF4]) were removed by filtration. Then the alkyne
MeO2CCtCCO2Me (0.150 mL, 1.22 ×10-4 mol) was added
slowly and the reaction mixture was refluxed for 2 h. After
this period, the solution was filtered out and the filtrate was
concentrated to dryness on a rotary evaporator, giving a deep
red solid, which was dissolved in the minimum amount of CH2-
Cl2 and passed through a SiO2 chromatography column (4.5
cm × 2 cm) using a CH2Cl2/MeOH (100/1) mixture as eluant.
The first yellow band collected was concentrated to dryness,
giving 80 mg of [Pd{[(MeO2CCdCCO2Me)(η5-C5H3)CHdN(CH2)3-
NMe2]Fe(η5-C5H5)}Cl] (7b), which arises from the monoinser-
tion of the alkyne. A small amount (15 mg) of [Pd{[(MeO2CCd
3J (H-H) ) 2.5 Hz); 5.39 (t, 1H, H5, J (H-H) ) 2.5 Hz); 8.21
3
(s, 1H, -CHdN-); 3.54 and 4.08 (m, 2H, dNCH2-); 2.38 and
2.40 (m, 2H, -CH2N); 2.81 (s, 3H, Me); 2.51 (s, 3H, Me); 3.73
and 3.71 (s, 6H, 2 -OMe); 5.25 (s, 2H, CH2Cl2). 13C{1H} NMR:
44
δ 70.9 (C5H5), 79.9 (C1); 72.4 (C2); 73.0 (C3); 75.0 (C4); 76.4
(C5); 169.6 (-CHdN-); 64.9 (dNCH2-); 62.1 (-CH2N-); 50.0
(Me); 47.7 (Me); 51.4 and 51.7 (2 OMe); 174.2 and 165.7 (2
-COO), 133.4 and 139.1 (CR and Câ of the inserted η2-alkene).
Characterization data for 7b are as follows. Anal. Calcd for
C
22H27FeClN2O4Pd‚1/2CH2Cl2: C, 43.33; H, 4.52; N, 4.49.
Found: C, 43.0; H, 4.5; N, 4.4. MS (FAB+): m/z 545 ([M -
Cl]+). IR: 1635 cm-1 (ν(>CdN-)), 1715 and 1693 cm-1
(ν(>COO)). H NMR:44 δ 4.17 (s, 5H, C5H5); 4.59 (s, 1H, H3);
1
3
(45) In this case, the signal due to the C2 nuclei was not observed.
4.63 (t, 1H, H4); 5.27 (t, 1H, H5, J (H-H) ) 2.5 Hz); 8.29 (s,

2408 Organometallics, Vol. 22, No. 12, 2003
Pe´rez et al.
Ta ble 7. Cr ysta l Da ta a n d Deta ils of th e Refin em en t of th e Cr ysta l Str u ctu r es of
[P d {[(P h CdCP h )2(η5-C5H3)CHdN(CH2)n NMe2]F e(η5-C5H5)}][BF 4]‚CH2Cl2 (n ) 2 (4a ), 3 (4b)),
[P d {[(EtCdCEt)2(η5-C5H3)CHdN(CH2)3NMe2]F e(η5-C5H5)}][BF 4]‚CH2Cl2 (5b), a n d
[P d {[(MeO2CCdCCO2Me)2(η5-C5H3)CHdN(CH2)3NMe2]F e(η5-C5H5)}Cl]‚CH2Cl2 (8b)
4a
4b
5b
8b
empirical formula
mol wt
C
43H39N2FePdBF4‚CH2Cl2
C
44H43N2FePdBF4‚CH2Cl2
C
28H41N2FePdBF4
C
29H35Cl3FeN2O8Pd
917.75
932.78
654.69
808.19
T (K)
293(2)
293(2)
293(2)
293(2)
λ (Å)
0.710 69
0.1 × 0.1× 0.2
rhombic
Pc21b
10.036(1)
18.672(1)
21.422(1)
90.0
90.0
4014.3(5)
4
1.519
0.995
0.710 69
0.1 × 0.1× 0.2
monoclinic
P21/c
20.528(1)
9.635(1)
21.695(1)
90.0
103.385(1)
4172.5(5)
4
1.485
0.959
0.710 69
0.1 × 0.1× 0.2
orthorhombic
Pc21/n
12.109(1)
14.665(1)
16.270(1)
90.0
90.0
2889.2(4)
4
1.505
1.170
0.710 69
0.1 × 0.1× 0.2
monoclinic
P21/n
13.757(1)
14.324(1)
16.958(1)
90.0
90.941(1)
3341.2(4)
4
1.607
1.262
cryst size (mm)
cryst syst
space group
a (Å)
b (Å)
c (Å)
R ) γ (deg)
â (deg)
V (Å3)
Z
Dcalcd (Mg m-3
)
µ (mm-1
F(000)
)
1864
1900
1344
1640
θ range for data
collecn (deg)
1.90-28.83
2.86-28.38
3.02-31.11
1.89-31.65
no. of collected rflns
no. of unique rflns (Rint
no. of params
19 243
4526 (0.0390)
523
10 604
4666 (0.0367)
598
13 452
3606 (0.0342)
335
13 816
8578 (0.0475)
427
)
goodness of fit
refinement method
R indices (I >2σ(I))
0.854
1.000
1.062
1.048
full-matrix least-squares on F2
R1 ) 0.0395,
wR2 ) 0.0894
R1 ) 0.1386,
wR2 ) 0.1021
0.04(3)
R1 ) 0.0302,
wR2 ) 0.0751
R1 ) 0.0536,
wR2 ) 0.0807
R1 ) 0.0389,
wR2 ) 0.0900
R1 ) 0.0498,
wR2 ) 0.0950
0.06(4)
R1 ) 0.0345,
wR2 ) 0.0836
R1 ) 0.0746,
wR2 ) 0.0909
R indices (all data)
abs structure param
largest diff peak,
0.288, -0.338
0.683, -0.371
0.534, -0.636
0.494, -0.334
hole (e Å-3
)
1H, -CHdN-); 3.56 and 4.04 (m, 2H, dNCH2-); 1.87 and 2.27
(m, 2H, -CH2-); 2.26 and 2.74 (m, 2H, -CH2N-); 2.49 (s, 3H,
Me); 2.24 (s, 3H, Me); 3.75 (s, 6H, 2 OMe); 5.25 (s, 2H, CH2-
Cl2). 13C{1H} NMR:44 δ 70.7 (C5H5); 81.2 (C1); 76.6 (C2); 72.3
(C3); 72.1 (C4); 76.4 (C5); 168.4 (-CHdN-); 60.4 (dNCH2-);
26.0 (-CH2-); 59.7 (-CH2N); 50.0 (Me); 48.5 (Me), 51.5 and
51.6 (2 OMe); 172.7 and 164.3 (2 -COO); 129.9 and 144.0 (CR
and Câ of the alkene).
Cr ysta l Str u ctu r e Deter m in a tion a n d Refin em en t. A
prismatic crystal of 4a ,b, 5b, or 8b (sizes in Table 7) was
selected and mounted on a MAR345 diffractometer with an
image plate detector. Unit cell parameters were determined
from automatic centering of 7351 (for 4a ), 7482 (for 4b), 13 452
(for 5b), or 13 816 (for 7b) reflections in the range 3° e θ e
31° and refined by a least-squares method. Intensities were
collected with graphite-monochromated Mo KR radiation. The
numbers of measured reflections were 19 243 (for 4a in the
range 1.90° e θ e 28.83°), 10 604 (for 4b in the range 3° e θ
e 31°), 13 452 (for 5b in the range 3.02° e θ e 31.11°), and
8578 (for 8b in the range 1.89° e θ e 31.65°). The numbers of
reflections which were nonequivalent by symmetry were 4526
(Rint(on I) ) 0.039) for 4a , 4666 for 4b (Rint(on I) ) 0.036), 3606
(Rint(on I) ) 0.034) for 5b, and 8578 (Rint(on I) ) 0.0475). The
numbers of reflections assumed as observed, applying the
condition I > 2σ(I), were 2225 (for 4a ), 3537 (for 4b), 3099 (for
5b), and 6055 (for 8b). Lorentz-polarization corrections were
made, but absorption corrections were not.
squares methods with the SHELX97 computer program47
using 4256 (for 4a ), 4666 (for 4b), 3606 (for 5b), and 8578 (for
8b) reflections (very negative intensities were not assumed).
2
In the four cases the function minimized was ∑w||Fo|
-
|Fc| | , with w ) [σ2(I) + (0.0610P)2]-1 (for 4a ), w ) [σ2(I) +
(0.0536P)2]-1 (for 4b), w ) [σ2(I) + (0.0434P)2]-1 (for 5b), w )
[σ2(I) + (0.0498P)2]-1 (for 5b), and w ) [σ2(I) + (0.0610P)2]-1
(for 8b) and P ) (|Fo| + 2|Fc| )/3; ×c4, ×c4 ′, and ×c4 ′′ were
taken from the literature.48 The chiralities of the structures
of 4a and 5b were defined from the Flack coefficient,49 which
is equal to 0.04(3) for 4a and 0.06(4) for 5b.
2
2
2
2
Ack n ow led gm en t. We are grateful to the Ministe-
rio de Ciencia y Tecnolog´ıa of Spain and to the Gener-
alitat de Catalunya for financial support (Grant Nos.
BQU2000-0652 and SGR-2001-00054). S.P. thanks the
Generalitat de Catalunya for a predoctoral fellowship.
Su p p or tin g In for m a tion Ava ila ble: Tables containing
crystal data and structure refinement details, atomic coordi-
nates and equivalent isotropic parameters, all bond lengths
and angles, hydrogen bond lengths and angles, anisotropic
displacement parameters, and hydrogen coordinates for com-
pounds 4a ,b, 5b, and 8b (Tables S1-S21). This material is
available free of charge via the Internet at http://pubs.acs.org.
OM021036Y
The structures were solved by direct methods using the
(47) Sheldrick, G. M. SHELX97: A Computer Program for Deter-
mination of Crystal Structures; University of Go¨ttingen, Go¨ttingen,
Germany, 1997.
SHELXS computer program46 and refined by full-matrix least-
(46) Sheldrick, G. M. SHELXS: A Computer Program for Determi-
nation of Crystal Structures; University of Go¨ttingen, Go¨ttingen,
Germany, 1997.
(48) International Tables of X-ray Crystallography; Kynoch Press:
Birmingham, U.K., 1974; Vol. IV, pp 99-100, 149.
(49) Flack, H. D. Acta Crystallogr. 1983, A39, 876.