Nucleophilic addition of 1,3-dicarbonyl compounds as a route to functionalized cyclopalladated complexes with chelated 1,1-bis(diphenylphosphino)ethene

Article abstract of DOI:10.1039/b203864a

Treatment of the chloride-bridged complex [Pd{2,4-(OMe)₂C₆H₂C(H)=N(Cy)-C6,N} (μm-Cl)]₂ (1) with 1,1-bis(diphenylphosphino)ethene (vdpp) and NH₄PF₆ or NaClO₄ in 1:2 molar ratio afforded the mononuclear cyclometallated palladium(II) complexes [Pd{2,4-(OMe₂)C₆H₂C(H)=N(Cy)-C6,N}{ (Ph₂P)₂C=CH₂-P,P′}](X) (2, X = PF₆; 3, X = ClO₄). The structure of 2 has been determined by X-ray diffraction analysis. Reaction of 2 with acetylacetone in the presence of anhydrous sodium carbonate yielded in high yield the addition product [Pd{2,4-(MeO)₂C₆H₂C(H)=N(Cy)-C6,N}{ (Ph₂P)₂CHCH₂CH(COMe)₂-P, P′}](PF₆) (4). The ³¹P-{¹H} NMR spectrum showed a greater ²J(PP) coupling constant than the one observed for the starting complex. Reaction of 2 with diethyl malonate afforded a 7:3 mixture of the addition product [Pd{2,4-(MeO)₂C₆H₂C(H)=N(Cy)-C6,N}{ (Ph₂P)₂CHCH₂CH(COOEt)₂-P, P′}](PF₆) (5) and the starting complex. The desired addition compound could be isolated in pure form by treatment of 3 with diethyl malonate yielding [Pd{2,4-(MeO)₂C₆H₂C(H)=N(Cy)-C6,N}{ (Ph₂P)₂CHCH₂CH(COOEt)₂-P, P′}](ClO₄) (16). The reaction of 2 with asymmetric nucleophiles such as methyl acetoacetate, ethyl propionylacetate, ethyl acetoacetate, methyl 4-chloroacetoacetate, 1,1,1-trifluoroacetylacetone and thenoyltrifluoroacetone afforded the corresponding addition derivatives, [Pd{2,4-(MeO)₂C₆H₂C(H)=N(Cy)-C6,N}{ (PH₂P)₂CHCH₂CH(COR₁)(COR ₂)-P,P′}]-(PF₆) (R₁ = Me, R₂ = OMe, 6; R₁ = Et, R₂ = OEt, 7; R₁ = Me, R₂ = OEt, 8; R₁ = CH₂Cl, R₂ = OMe, 9; R₁ = Me, R₂ = CF₃, 10; R₁ = CF₃, R₂ = 2-SC₄H₃, 11). The NMR spectra showed some resonances were duplicated, suggesting the existence of optical isomers, as a consequence of the existence of two chiral carbon atoms in the diphosphine moiety, (Ph₂P)₂C*HCH₂C*H(COR ₁)(COR₂). The molecular structure of compound 7 has been determined by X-ray crystallography confirming the spectroscopic data. The crystal structure of 7 comprises equimolar amounts of the (C16R, C18S) and (C16S, C18R) enantiomers. Reaction of 2 with 1-(2-furyl)-1,3-butanedione, ethyl 2-methylacetoacetate, 3-chloroacetylacetone and methyl 2-chloroacetoacetate gave compounds [Pd{2,4-(MeO)₂C₆H₂C(H)=N(Cy)-C6,N}{ (Ph₂P)₂CHCH₂C(R₁)(COMe) (COR₂)-P,P′}](PF₆) (R₁ = H, R₂ = 2-OC₄H₃, 12; R₁ = Me, R₂ = OEt, 13; R₁ = Cl, R₂ = Me, 14; R₁ = Cl, R₂ = OMe, 15). The ²J(PP) coupling constants for 14 and 15 were smaller than in the other addition compounds due to the presence of the neighbouring chlorine atom. Treatment of 2 with 3-ethylacetylacetone or 2,2,6,6-tetramethyl-3,5-heptanedione did not give any addition product. However, reaction of 3 with 3-ethylacetylacetone yielded a mixture of 3/[Pd{2,4-(MeO)₂C₆H₂C(H)=N(Cy)-C6,N}{ (Ph₂P)₂CHCH₂C(Et)(COMe)₂-P, P′}](ClO₄) (17) in 1:1 molar ratio.

Full text of DOI:10.1039/b203864a

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Nucleophilic addition of 1,3-dicarbonyl compounds as a route
to functionalized cyclopalladated complexes with chelated
1,1-bis(diphenylphosphino)ethene
a
Roberto Mosteiro, Alberto Fernandez, Margarita Lopez-Torres, Digna Vazquez-Garcıa,
a
a
a
´
Antonio Suarez, Jesus J. Fernandez* and Jose M. Vila*
´
´
´
a
a
b
´
´
´
´
a
´
Departamento de Quımica Fundamental, Universidad de A Corun˜a, 15071 A, Corun˜a, Spain.
E-mail: lujjfs@udc.es; Fax: +34/981-167065; Tel: +34/981-167000
b
´
´
Departamento de Quımica Inorganica, Universidad de Santiago de Compostela, 15782,
Santiago de Compostela, Spain. E-mail: qideport@usc.es; Fax: +34/981-595012;
Tel: +34/981-563100
Received (in London, UK) 22nd April 2002, Accepted 17th July 2002
First published as an Advance Article on the web 20th August 2002
=
Treatment of the chloride-bridged complex [Pd{2,4-(OMe)2C6H2C(H) N(Cy)-C6,N}(m-Cl)]2 (1) with 1,1-
bis(diphenylphosphino)ethene (vdpp) and NH4PF6 or NaClO4 in 1:2 molar ratio afforded the mononuclear
0
=
=
cyclometallated palladium(II) complexes [Pd{2,4-(OMe2)C6H2C(H) N(Cy)-C6,N}{(Ph2P)2C CH2-P,P }](X)
(2, X ¼ PF6 ; 3, X ¼ ClO4). The structure of 2 has been determined by X-ray diffraction analysis. Reaction of 2
with acetylacetone in the presence of anhydrous sodium carbonate yielded0in high yield the addition product
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2CH(COMe)2-P,P }](PF6) (4). The 31P-{1H} NMR
spectrum showed a greater 2J(PP) coupling constant than the one observed for the starting complex. Reaction
=
=
of 2 with diethyl malonate afforded a 7:3 mixture of the addition product [Pd{2,4-(MeO)2C6H2C(H) N(Cy)-
C6,N}{(Ph2P)2CHCH2CH(COOEt)2-P,P0}](PF6) (5) and the starting complex. The desired addition compound
could be isolated in pure form by treatment of 3 with diethyl malonate yielding [Pd{2,4-
0
=
(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2CH(COOEt)2-P,P }](ClO4) (16). The reaction of 2 with
asymmetric nucleophiles such as methyl acetoacetate, ethyl propionylacetate, ethyl acetoacetate, methyl 4-
chloroacetoacetate, 1,1,1-trifluoroacetylacetone and thenoyltrifluoroacetone afforded the corresponding
0
=
addition derivatives, [Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(PH2P)2CHCH2CH(COR1)(COR2)-P,P }]-
(PF6) (R1 ¼ Me, R2 ¼ OMe, 6; R1 ¼ Et, R2 ¼ OEt, 7; R1 ¼ Me, R2 ¼ OEt, 8; R1 ¼ CH2Cl, R2 ¼ OMe, 9;
R1 ¼ Me, R2 ¼ CF3 , 10; R1 ¼ CF3 , R2 ¼ 2-SC4H3 , 11). The NMR spectra showed some resonances were
duplicated, suggesting the existence of optical isomers, as a consequence of the existence of two chiral carbon
atoms in the diphosphine moiety, (Ph2P)2C*HCH2C*H(COR1)(COR2). The molecular structure of compound
7 has been determined by X-ray crystallography confirming the spectroscopic data. The crystal structure of 7
comprises equimolar amounts of the (C16R, C18S) and (C16S, C18R) enantiomers. Reaction of 2 with 1-(2-
furyl)-1,3-butanedione, ethyl 2-methylacetoacetate, 3-chloroacetylacetone and methyl 2-chloroacetoac0etate
=
gave compounds [Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2C(R1)(COMe)(COR2)-P,P }](PF6)
(R1 ¼ H, R2 ¼ 2-OC4H3 , 12; R1 ¼ Me, R2 ¼ OEt, 13; R1 ¼ Cl, R2 ¼ Me, 14; R1 ¼ Cl, R2 ¼ OMe, 15). The
2J(PP) coupling constants for 14 and 15 were smaller than in the other addition compounds due to the presence
of the neighbouring chlorine atom. Treatment of 2 with 3-ethylacetylacetone or 2,2,6,6-tetramethyl-3,5-
heptanedione did not give any addition product. However, reaction of 3 with 3-ethylacetylacetone yielded a
0
=
mixture of 3/[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2C(Et)(COMe)2-P,P }](ClO4) (17) in 1:1
molar ratio.
dently and then integrated into a metal coordination sphere
Introduction
or constructed via direct reaction on a phosphine ligand when
already coordinated to the metal center. Typical examples are
the C–H acidity of the methylene group in Ph2PCH2PPh2
(bis(diphenylphosphino)methane, dppm)2 or the activated
=
vinylidene group of (Ph2P)2C CH2 , 1,1-bis(diphenylphos-
phino)ethene (vdpp).
Ligands having two or more phosphorus atoms play a sub-
stantial and still growing role in coordination and in organo-
metallic chemistry, owing to their wide range of steric and
electronic specifications suitable for a great variety of applica-
tions such as their use in catalytic processes or their ability to
stabilize different oxidation states, as well as to form homo-
and heteropolymetallic complexes.1
Nevertheless, little work has been reported relative to the
design and availability of new types of phosphines: probably
due to the often multistage synthetic methods required, which
are not adaptable to the preparation of new functionalized
phosphines. These ligands may either be prepared indepen-
=
(Ph2P)2C CH2 is well known as a versatile ligand in coordi-
nation chemistry. It can act as mono- or bidentate towards one
metal atom and it may also give polynuclear complexes with or
without metal–metal bonds. The presence of a carbon–carbon
double bond has aroused interest in the study of its addition
reactions. On the one hand, it has been shown that vdpp is
scarcely susceptible to nucleophilic attack and reacts directly
DOI: 10.1039/b203864a
New J. Chem., 2002, 26, 1425–1432
1425
This journal is # The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2002

View Article Online
only in the presence of a strong base (i.e., KtBuO) with
3
molecules such as phosphines and arsines,
quaternization of both phosphorus atoms by reaction with
or when the
=
MeI or MeSO3F promotes additional activation in the C C
bond.4
On the other hand, coordination to different metallic centres
=
strongly activates the C C bond towards the nucleophilic
attack of species HNu, probably due to an additional induced
polarization of the double bond in the starting complex and a
relief of angle strain at the carbon adjacent to both phosphorus
atoms after addition. Many different metal fragments promote
these type of reactions when complexed to vdpp, which gener-
ally is acting as a chelating ligand, such as in the tetracarbonyl
derivatives of group six metals,5 Fe(0)6 and Ru(II)7 com-
pounds, Pd(II), Pt(II) and Pt(IV) salts,8 or Au(III) complexes;9
even Au(I) compounds with an A-frame structure in which
the phosphine is acting as a bridging ligand may undergo addi-
tion reactions.10 Coupling reactions of vdpp can be achieved
by treatment with lithium via coordination of the alkali metal
to the phosphine.11
Scheme 1
Cyclometallated complexes are well documented for a great
variety of metal centres and ligands. These compounds are suc-
cessfully used in organic synthesis,12 catalysis,13 photochemis-
try14 and optical resolution procesess,15 and are rather
promising as potential biologically active materials16 and
liquid crystals.17 We have been interested in cyclopalladation
reactions of differently substituted Schiff base ligands derived
from [C,N,X] (X ¼ O, S, N) terdentate ligands18 or [C,N]
Schiff bases,19 as well as imidazoles20 and ferrocenylimines.21
We have recently reported that a cyclometallated moiety is
isotopes.27 The conductivity data (125–150 Oꢀ1 cm2 molꢀ1 in
10ꢀ3 mol dmꢀ3 solutions in dry acetonitrile) showed them to
1
be 1:1 electrolytes.28 The HC N resonance in the H NMR
=
spectra at d 8.45 appeared as a doublet due to coupling with
the 31P nucleus trans to nitrogen [4J(PHi) ¼ 8.3 Hz], whilst
the H5 resonance appeared as a multiplet by coupling to H3
and to both 31P nuclei, as we have found in related systems.29
The H5 and 4-OMe proton signals were shifted to lower fre-
quency by ca. 0.6 ppm, with respect to their position in the
spectrum of the starting product, due to the shielding effect
=
capable of polarizing the C CH2 double bond of vdpp to
afford addition products with different primary and secondary
amines22 and we now present the synthesis of cyclometallated
compounds derived from functionalized diphosphine ligands
with pendant 1,3-dicarbonylic arms.
Results and discussion
For the convenience of the reader the compounds and reac-
tions are shown in Schemes 1 and 2. Treatment of [{Pd[2,4-
=
(OMe)2C6H2C(H) N(Cy)-C6,N]}(m-CH3CO2)]2 , a dinuclear
cyclometallated complex with acetate-bridging ligands,23 with
aqueous sodium chloride, in a metathesis reaction, afforded
=
the chloride-bridged complex [{Pd[2,4-(OMe)2C6H2C(H)
N(Cy)-C6,N]}(m-Cl)]2 , 1. Nitrogen coordination to metal cen-
ter was supported by the shift towards lower frequency in the
=
IR spectrum of the n(C N) stretching vibration with respect to
the corresponding one in the free imine (1579 and 1640 cmꢀ1
=
,
respectively)24 and by the upfield shift of the HC N proton
resonance in the 1H NMR spectrum ca. 0.7 ppm from its posi-
tion in the spectrum of the free ligand (d 8.00 and d 8.64,
1
respectively).25 In the H NMR spectrum, two doublets at d
6.06 and d 6.58 assigned to the H3 and H5 protons
[4J(H3H5) ¼ 2.0 Hz], respectively, evidenced C6–Pd metalla-
tion. The IR spectra showed two n(Pd–Cl) bands, at 295 and
289 cmꢀ1, consistent with an asymmetric Pd2Cl2 bridging
unit.26
The mononuclear cyclometallated palladium(II) complexes
=
=
[{Pd[2,4-(OMe2)C6H2C(H) N(Cy)-C6,N]}{(Ph2P)2C CH2-
P,P0}](X) (2, X ¼ PF6 ; 3, X ¼ ClO4) were prepared by treat-
ment of complex 1 with vdpp in 1:2 molar ratio, and ammo-
nium hexafluorophosphate or sodium perchlorate as
appropriate, in acetone at room temperature. The IR spectra
showed, as the main difference from the starting material,
bands at 850 br and 1080 s cmꢀ1, arising from the correspond-
ꢀ
ing counterions, PF6 and ClO4ꢀ, respectively. The FAB-MS
spectra showed the corresponding peaks at m/z 748 assigned
to [M]+ (M corresponding to the fragment due to the loss of
ꢀ
ꢀ
the PF6 or ClO4 ion), after consideration of the palladium
Scheme 2
1426
New J. Chem., 2002, 26, 1425–1432

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of the phosphine phenyl rings cis to the metallated carbon
atom. The 31P-{1H} NMR spectra showed two doublets
[2J(PAPB) ca. 16.5 Hz], indicating the two phosphorus atoms
to be non-equivalent in each case; the assignment of the doub-
lets was made in accordance with the assumption that a ligand
of greater trans influence shifts the resonance of the phos-
phorus atoms trans to it to lower frequency.30 The 13C-{1H}
NMR spectrum of compound 2 showed resonances at d
170.9 [t, 3J(PC) ¼ 3.5 Hz] and d 165.0 [dd, 2J(PC) ¼ 122.8,
Fig. 1
=
5.0 Hz] assignable to HC N and C6, respectively, downfield
CHCH2CH-(COMe)(COOMe)-P,P0}](PF6), 6, in high yield
=
shifted from the spectrum of the free ligand (ca. 15 and 35
ppm, also respectively),23 thereby confirming that cyclometal-
(90%). The IR spectrum showed two n(C O) bands: one at
1720 cmꢀ1, assigned to the C(O)Me group, and another one
at 1741 cmꢀ1, shifted towards higher wavenumbers, assigned
to the C(O)OMe group.32 The FAB-MS spectrum showed,
among others, a peak corresponding to [M]+ at m/z 864. In
the 1H NMR spectrum, four singlets were assigned to the
methyl groups of the b-ketoester moiety, instead of the
expected two, at d 3.67 and d 3.62 (CO2Me), and at d 1.97
and d 1.80 (COMe). This was also the case for the H5 and
4-MeO proton resonances of the cyclopalladated moiety.
Thus, two multiplets at d 5.69 and d 5.64 were ascribed to
the H5 resonance, and two singlets at d 3.20 and d 3.18 to
the 4-MeO group. Likewise, the 31P-{1H} NMR spectrum
showed two pairs of doublets. These results suggest the pre-
sence of optical isomers due to the existence of two chiral car-
bon atoms, after addition of the asymmetric nucleophile
(Ph2P)2CHCH2CH(COR1)(COR2): one situated in the a posi-
tion with respect to the phosphorus atoms, and the other one
situated in the a position to the carbonyl groups; whereas reac-
tion with symmetric derivatives only produced one chiral cen-
ter, i.e., the PCP carbon atom (see Fig. 1). The relative ratio of
the optical isomers was 1:1, as calculated from the integrals in
the NMR spectra.
lation was maintained.31 The C CH2 resonances appeared at
=
d
146.6 [dd, 1J(PC) ¼ 30.2, 20.6 Hz] and
d 138.1 [t,
2J(PC) ¼ 5.7 Hz], and were assigned to the a- and b-carbon
atoms, C13 and C14, respectively. These findings were con-
firmed by the X-ray crystal structure determination of com-
pound 2 (see below).
Reaction of 2 with acetylacetone, a symmetric 2,4-dicar-
bonylic derivative, in dry chloroform for 2 hours at 45 ꢁC
and inert atmosphere in the presence of anhydrous sodium car-
bonate yielded the addition product, [Pd{2,4-(MeO)2-
0
=
C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2CH(COMe)2-P,P }]
(PF6), 4, quantitatively (yield 95%). Attempts to synthesize 4 in
the absence of the carbonate salt failed. The FAB-MS spectra
showed a peak corresponding to [M]+ at m/z 848. Other
intense fragmentation peaks at m/z 537 and 291 were assigned
to [Pd(L)(PPh2)]+ and [Pd(PPh2)]+, respectively; they were also
present in the spectra of other complexes synthesized from 2
(vide infra). The IR absorptions of 4 at 1725 and 1705 cmꢀ1
=
were consistent with the presence of two C O groups. The
1H NMR spectrum exhibited substantial differences with
respect to the starting material. Thus, the resonance of the
vinylidene protons in 2 was absent and a multiplet at ca. d
4.80 assignable to the P2CH proton appeared; the resonance
due to the (Ph2P)2CHCH2 protons overlapped with those of
the methylene groups from the cyclohexyl ring. The 1,3-dicar-
bonyl moiety proton resonances were clearly distinguished: a
triplet at d 3.94 [3J(HH) ¼ 6.8 Hz] assignable to the a-proton
H15, and two singlets at d 1.94 and d 1.85 assigned to the non-
equivalent COMe methyl groups. The 31P-{1H} NMR spec-
trum showed two doublets assigned to the two inequivalent
Other asymmetric nucleophiles were tested, such as ethyl
propionylacetate, ethyl acetoacetate and methyl 4-chloroace-
toacetate, which yielded the corresponding addition products,
7–9, in good yield (ca. 85%). Their mass and NMR spectra
showed a similar pattern to that found for compound 6 (see
Experimental section). The proposed structure for compound
7 has been confirmed by X-ray diffraction analysis (see below).
Treatment of 2 with 1,1,1-trifluoroacetylacetone and thenoyl-
trifluoroacetone also afforded the corresponding addition pro-
ducts. The 31P-{1H} NMR spectra for compounds 10 and 11
only showed two doublets at ca. d 12 and d ꢀ8, [2J(PP) ca.
53 Hz, see Experimental section], in spite of their asymmetric
nature. However, in the corresponding 19F NMR spectra
two singlets were ascribed to the CF3 resonance at ca. d ꢀ71
and d ꢀ75 in each case.
phosphorus atoms with
a
greater coupling constant
[2J(PP) ¼ 55.1 Hz] than the one observed for the starting com-
plex, in spite of the fact that the P–C–P carbon atom in 2
shows sp2 hybridization, as opposed to the sp3 hybridization
of the same carbon atom in 4; a similar trend has been
observed by us in the addition reaction with amines.22 We rea-
soned then that the contribution of 2J(PP) across the metal
center (normally of negative sign) is greater in the addition
products than in 2, thus lowering the absolute value of the cou-
pling constant. The 13C-{1H} NMR spectrum confirmed addi-
tion showing the C13 and C14, resonances, d 50.7 and d 26.9,
respectively, shifted to high field and in the expected range for
Reaction of 2 with 1-(2-furyl)-1,3-butanedione, ethyl 2-
methylacetoacetate, 3-chloroacetylacetone and methyl 2-chlor-
oacetoacetate
=
gave
compounds
[Pd{2,4-(MeO)2C6H2
C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2C(R1)(COMe)-(COR2)-
P,P0}](PF6) (R1 ¼ H, R2 ¼ 2-OC4H3 , 12; R1 ¼ Me,
R2 ¼ OEt, 13; R1 ¼ Cl, R2 ¼ Me, 14; R1 ¼ Cl, R2 ¼ OMe,
15). In the 1H and 13C NMR spectra of compounds 12 and
14 some resonances appeared duplicated, especially those cor-
responding to the 1,3-dicarbonyl moiety (see Experimental sec-
tion). The PCHP proton resonance was shifted to lower
frequency and was overlapped by the cyclohexyl ring signals.
The 31P-{1H} NMR spectra of compound 14 showed two
doublets, whereas in the case of compounds 12, 13 and 15 four
doublets were observed, as expected. The presence of the
neighbouring chlorine atom shifted the phosphorus resonances
tolowerfieldwithrespecttootherderivatives(ca. 28and12ppm,
for PA and PB , respectively). An interesting feature of these
=
an aliphatic carbon atom consequent on the C CH2 to
CH2CH2 change upon addition. Four singlets, at d 203.3 and
d 203.1, and at d 29.7 and d 29.6, were assigned to the COMe
and COMe resonances, respectively. The C15 resonance
appeared at d 64.1 as a triplet [3J(PC) ¼ 4.3 Hz].
Under similar conditions reaction of 2 with the symmetric
1,3-diester diethyl malonate yielded a 7:3 mixture (as calcu-
lated from the integrals in the 1H NMR spectrum) of the
desired addition product 5 (in ca. 60% yield) and the starting
complex, presumably as a consequence of the less acidic char-
acter of this nucleophile as compared with acetylacetone. The
1H NMR spectrum of the mixture showed two signals at d 1.19
and d 1.15 assignable to the OCH2Me methyl group in the
addition product.
2
spectra was the J(PAPB) value, which was smaller in the case
of the chlorine derivatives that in the other addition compounds
(ca. 30 Hz vs. > 52 Hz). The FAB-MS spectrum of compounds
12 and 13 showed peaks at m/z 900 ([M]+), and 892 ([M]+) and
878 ([MH ꢀ Me]+), respectively. In the mass spectrum for
Treatment of 2 with the b-ketoester methyl acetoacetate
=
afforded [Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2-
New J. Chem., 2002, 26, 1425–1432
1427

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Fig. 2
complex 14 a very weak peak at m/z 882 was assigned to [M]+,
and a very intense one at m/z 846 was assigned to [M ꢀ HCl]+,
the spectrum of compound 15 only registered the peak at m/z
862, corresponding to [M ꢀ HCl]+. We performed the electro-
spray mass spectra for complexes 14 and 15, thereby confirming
the presence of the [M]+ peak. We suggest an additional interac-
tion between the PCHP hydrogen atom and the chlorine atom in
a five-membered ring, as depicted in Fig. 2, which made reason-
able these peculiar findings.
Fig. 4 Molecular structure of the cation for [Pd{2,4-(MeO)2
0
=
C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2CH(COEt)(COOEt)-P,P }]
(PF6) (7), with labelling scheme. Hydrogen atoms have been omitted
for clarity.
Treatment of 2 with 3-ethylacetylacetone did not give any
addition product, regardless of the reaction conditions used,
even when a large excess of the nucleophile was added. The
presence of the ethyl substituent in the a position to both car-
crete molecules, separated by normal van der Waals distances.
The crystal structure of 2 comprises two molecules per asym-
metric unit, both having very similar bond distances and
angles; discussion will be limited to only one. The crystal struc-
ture of 7 comprises equimolar amounts of the (C16R, C18S)
and (C16S, C18R) enantiomers. Crystallographic data and
selected interatomic distances and angles are listed in Tables
1 and 2.
=
bonyl groups did not allow addition to the C CH2 double
bond of the coordinated diphosphine, presumably due to steric
hindrance by the phenyl rings of the diphosphine ligand, as
opposed to the less sterically demanding methyl or chlorine
groups, which afforded compounds 13–15. Other bulky substi-
=
tuents, such as tert-butyl groups linked to the C( O) moieties
in 2,2,6,6-tetramethyl-3,5-heptanedione, also impeded addi-
tion, and no change in the starting complex was observed.
In analogous processes, compound 3 showed similar beha-
vior to compound 2 when treated with the dicarbonyl com-
pounds mentioned above. Furthermore, when 3 was treated
with diethylmalonate the desired addition compound 16 could
be isolated in pure form, in contrast to the analogous reaction
with 2, in which the corresponding product 5 was contami-
nated with the starting cyclometallated compound (see above).
Reaction of 3 with 3-ethylacetylacetone, which did not react
with complex 2, yielded a mixture of 3 and 17 in 1:1 molar
ratio. The effect of the counterion in these type of processes
is not clear, but this work is currently being developed by us.
The coordination sphere around each palladium atom con-
sists of a nitrogen atom of the imine group, an ortho carbon
atom of the phenyl ring, and two phosphorus atoms from a
chelating diphospine ligand in a slightly distorted square-
planar coordination environment. The sums of angles at palla-
dium are 359.97ꢁ (2) and 359.22ꢁ (7), with the distortions more
noticeable in the somewhat reduced ‘‘bite’’ angles C(6)–Pd(1)–
N(1) consequent upon chelation [81.0 (3)ꢁ (2) and 80.7(2)ꢁ (7),
and P(1)–Pd(1)–P(2) ¼ 73.27(7)ꢁ (2) and 72.24(6)ꢁ (7), respec-
tively]. The requirements of the five- and four-membered che-
late rings force the bond angles P(1)–Pd(1)–P(2) to 73.27(7)ꢁ
(2) and 72.25(6)ꢁ (7), P(1)–C(16)sp2–P(2) to 98.4(4)ꢁ (2) and
P(1)–C(16)sp3–P(2) to 95.1(3)ꢁ (7). The latter ones represent a
Molecular structures of complexes 2 and 7
Table 1 Crystal and structure refinement data for complexes 2 and 7
Suitable crystals were grown by diffusion of diethyl ether in
chloroform solutions of complexes 2 and 7. The labelling
schemes for the complexes are shown in Fig. 3 and 4 (see
Experimental section for data). Both structures consist of dis-
2
7
Formula
Mr
Temperature/K
C
894.07
41H42F6NO2P3Pd
C48H54F6NO5P3Pd
1038.23
293(2)
293(2)
0.71073
Triclinic
˚
Wavelength/A
0.71073
Monoclinic
P21/c
Crystal system
Space group
Cell dimensions:
¯
P1
˚
a/A
16.948(1)
17.549(1)
18.007(1)
61.780(1)
64.065(1)
66.171(1)
4110.7(1)
4
21.054(1)
9.7220(1)
23.338(1)
˚
b/A
˚
c/A
a/ꢁ
b/ꢁ
g/ꢁ
90.661(1)
3
˚
V/A
4776.7(2)
4
Z
Crystal size/mm3
m/mmꢀ1
0.25 ꢂ 0.20 ꢂ 0.15
0.631
1.3 to 25.0
0.40 ꢂ 0.40 ꢂ 0.20
0.558
0.9 to 25.0
y range/ꢁ
Reflections:
collected
22 085
24 121
independent
R1 , wR2 [I > 2s(I)]
R1 , wR2 (aꢀll3data)
14 094 (Rint ¼ 0.0307)
0.0688, 0.1671
0.1151, 0.2027
1.121
8401 (Rint ¼ 0.0670)
0.0550, 0.1417
0.1069, 0.1854
0.855
Fig. 3 Molecular structure of the cation for Pd{2,4-
0
=
(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2C CH2-P,P }](PF6)
=
(2),
with labelling scheme. Hydrogen atoms have been omitted for clarity.
˚
max r/e A
1428
New J. Chem., 2002, 26, 1425–1432

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ꢁ
˚
Table 2 Selected bond distances (A) and angles ( ) for complexes 2
and 7
(7). The chelate phosphine ring is not planar, with a mean
˚
˚
deviation from the ideal plane of 0.1329 A (2) and 0.1678 A
(7). The vinylidene carbon atoms, C(16) and C(17), show a dis-
placement from the plane formed by the metal center and the
phosphorus atoms (Pd(1), P(1), P(2), plane 3) of 0.4405 and
2
7
C(6)–Pd(1)
Pd(1)–N(1)
2.029(7)
2.094(6)
1.277(10)
1.439(10)
1.408(9)
2.257(2)
2.370(2)
1.816(8)
1.834(8)
1.301(10)
2.035(6)
2.102(5)
1.261(8)
1.449(8)
1.388(8)
2.2566(16)
2.3799(16)
1.853(6)
1.854(6)
1.517(9)
1.538(9)
1.499(13)
1.215(10)
1.493(11)
1.194(10)
80.7(2)
˚
˚
ꢀ1.0606 A (2), respectively; and ꢀ0.5583 and ꢀ0.3305 A (2),
also respectively. The angles between plane 3 and the previous
planes are as follows: plane 1/plane 3:6.0ꢁ and plane 2/plane
3:1.8ꢁ, for complex 2; and plane 1/plane 3:12.1ꢁ, plane 2/plane
3:9.9ꢁ, for complex 7.
N(1)–C(9)
C(9)–C(1)
C(1)–C(6)
Pd(1)–P(1)
˚
Pd(1)–P(2)
P(1)–C(16)
For complex 2, the C(16)–C(17) bond length is 1.301(10) A,
which is within the range expected for a carbon–carbon double
˚
bond and is shorter than the value of 1.34 A in free vdpp. Its
P(2)–C(16)
C(16)–C(17)
˚
corresponding value in compound 7 is 1.517(9) A, respectively,
consequent upon addition and is within the expected value for
C(17)–C(18)
C(18)–C(19)
˚
a single carbon–carbon bond (ca. 1.50 A). For complex 7 the
C(19)–O(3)
C(18)–C(48)
C(48)–O(4)
˚
carbon–oxygen bond lengths are C(19)–O(3) ¼ 1.215(10) A
˚
and C(48)–O(4) ¼ 1.194(10) A, and are within the expected
˚
value for a double bond C O (ca. 1.21 A), whereas the
=
C(6)–Pd(1)–N(1)
C(6)–Pd(1)–P(1)
N(1)–Pd(1)–P(2)
P(1)–Pd(1)–P(2)
P(1)–C(16)–P(2)
Pd(1)–P(1)–C(16)
Pd(1)–P(2)–C(16)
P(1)–C(16)–C(17)
P(2)–C(16)–C(17)
C(16)–C(17)–C(18)
C(17)–C(18)–C(19)
C(19)–C(18)–C(48)
C(17)–C(18)–C(48)
C(18)–C(19)–O(3)
C(18)–C(48)–O(4)
81.0(3)
99.4(2)
C(18)–C(19) and C(18)–C(48) bond distances, 1.499(13) and
˚
1.492(11) A, respectively, are in the corresponding range for
a single bond C–C, thereby confirming the presence of the
1,3-dicarbonyl moiety in its keto form.
98.05(17)
106.30(19)
73.27(7)
98.4(4)
108.54(14)
72.24(6)
95.1(3)
94.1(2)
90.0(2)
95.0(2)
91.04(19)
122.2(5)
124.8(5)
113.3(6)
114.5(7)
109.2(7)
110.8(7)
122.3(9)
123.6(9)
131.0(7)
129.9(7)
Experimental section
General remarks
Safety note. Perchlorate salts of metal complexes with
organic ligands are potentially explosive. Only small amounts
of these materials should be prepared and handled with great
caution.
All manipulations to synthesize the addition compounds
were performed under prepurified Ar using standard Schlenk
techniques. All solvents were distilled prior to use from appro-
priate drying agents.38 Ph2PC( CH2)PPh2 (vdpp) was pre-
=
smaller value than the corresponding one in free vdpp,
118.4ꢁ,33 although some four-membered chelate rings invol-
ving coordinated phosphines with a even smaller P–C–P angle
have been reported.34
pared according to procedures described elsewhere.39 All
other chemicals were used as supplied from commercial
sources. NMR spectra were obtained as CDCl3 solutions and
referenced to SiMe4 (1H, 13C-{1H}), 85% H3PO4 (31P-{1H})
or CFCl3 (19F); and were recorded on a Bruker AC-200F spec-
trometer (200.0 MHz for 1H, 50.3 MHz for 13C-{1H}, 81.0
MHz for 31P-{1H}, 188.3 MHz for 19F). IR spectra were
recorded as KBr pellets or Nujol mulls on a Perkin-Elmer
1330 spectrophotometer. Conductivity measurements were
made on a Crison GLP 32 conductivimeter using 10ꢀ3 M solu-
tions in dry acetonitrile at room temperature (298 K). Mass
spectra were obtained in a QUATRO mass spectrometer with
Cs ion-gun and 3-NBA matrix. Electrospray mass spectra
were recorded on a Finnigan Navigator spectrometer with
acetonitrile as the solvent. The synthesis of [{Pd-[2,4-
The palladium–nitrogen bond lengths, 2.094(6) (2) and
˚
2.103(5) A (7), are longer than the single bond predicted value
˚
of 2.011 A, based on the sum of covalent radii for nitrogen
2
35
(sp ) and palladium, 0.701 and 1.31 A, respectively, and
˚
reflects the trans influence of the phosphorus atom.29 The pal-
˚
ladium–carbon bond length, 2.029(7) (2) and 2.035(6) A (7),
˚
are within the expected value of 2.081 A (based on the sum
of covalent radii for carbon (sp2) and palladium, 0.771 and
˚
1.31 A, respectively), but longer than those found in related
complexes where partial multiple-bond character of the Pd–
C bond was proposed.20,36 This suggests some degree of multi-
ple-bond character in the Pd–C(aryl) linkage, and also reflects
the trans influence of the phosphorus atom for the observed
lengthening. The palladium–phosphorus bond distances are
shorter than the sum of the single bond radii for palladium
=
(OMe)2C6H2C(H) N(Cy)-C6,N]}(m-MeCO2)]2 was reported
in a recent paper from this laboratory.23
˚
and phosphorus, 2.41 A, suggesting some partial double bond
between both atoms and it is similar to others reported ear-
lier.37 The differing trans influence of the phenyl carbon and
imine nitrogen atoms is clearly illustrated by the palladium–
phosphorus distance trans to carbon, Pd(1)–P(1), and trans
Syntheses of the addition compounds
=
[{Pd[2,4-(OMe)2C6H2C(H) N(Cy)-C6,N]}{l-Cl)]2 , 1. An
aqueous solution of 10ꢀ2 M NaCl (ca. 25 mL) was added
˚
=
to nitrogen, Pd(1)–P(2), [i.e., Pd(1)–P(1) ¼ 2.257(2) A vs.
dropwise to [{Pd-[2,4-(OMe)2C6H2C(H) N(Cy)-C6,N]}(m-
˚
˚
Pd(1)–P(2) ¼ 2.370(2) A, 2; Pd(1)–P(1) ¼ 2.2567(16) A vs.
MeCO2)]2 (300 mg, 0.364 mmol) in acetone (ca. 25 mL). The
mixture was stirred for 12 hours after which a pale yellow solid
precipitated which was filtered off, washed with water (2 ꢂ 3
mL) and dried in vacuo over anhidrous CaCl2 . Yield: 98%.
=
˚
Pd(1)–P(2) ¼ 2.3799(16) A, 7].
Except for the methoxy and the cyclohexyl groups, the
cyclopalladated moiety is nearly planar. The mean deviations
from the least squares planes determined for the metallated
phenyl ring (C1, C2, C3, C4, C5, C6; plane 1) and the metalla-
IR: n(C N): 1579 s; n(Pd–Cltrans-N) 295m, n(Pd–Cltrans-C
)
280m. FAB-MS: 663 [MH ꢀ Cl ꢀ (MeO)2 ꢀ Me]+, 647
[MH ꢀ Cl ꢀ (MeO)3]+. 1H NMR: 8.00 (s, Hi); 6.58 (d, H5 ,
4J(H3H5) ¼ 2.0 Hz); 6.06 (d, H3); 3.82, 3.76 (s, 2-OMe,
4-OMe).
˚
cycle (Pd1, C1, C6, C9, N1; plane 2) are 0.0069 and 0.0074 A
˚
˚
(2), respectively; and 0.0029 A and 0.0208 A (7), also respec-
tively. The angles between these planes are 4.2ꢁ (4) and 1.2ꢁ
New J. Chem., 2002, 26, 1425–1432
1429

View Article Online
1
=
=
Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2C CH2-
P,P0}](PF6), 2. To a solution of 1 (200 mg, 0.258 mmol) in acet-
one (ca. 25 mL), vdpp (204 mg, 0.516 mmol) was added. The
mixture was stirred for 30 minutes at room temperature, after
which ammonium hexafluorophosphate (85 mg, 0.521 mmol)
was added, the resultant solution stirred for a further 30 min-
utes, water (ca. 25 mL) added dropwise and the resulting mix-
ture stirred for 12 hours. A pale yellow precipitate which
formed was filtered off, washed with water (2 ꢂ 3 mL) and
dried in vacuo over anhydrous CaCl2 . The desired complex
was recrystallized from a chloroform solution by gaseous diffu-
the integrals in the H NMR spectra) of the desired addition
product 5 and the starting complex 2. It was not possible to
obtain 5 in pure form by either recrystallization or column
chromatography. Overall yield: 86%, ca. 60% relative to 5.
1H NMR: 8.43 (d, Hi, 4J(PHi) ¼ 8.3 Hz); 6.07 (d, H3 ,
4J(H3H5) ¼ 2.0 Hz); 5.66 (m, H5); 4.80 (m, PCHP); 4.12 (m,
CO2CH2); 3.79 (s, 2-OMe); 3.23 (s, 4-OMe); 3.01 (t, H15
,
3J(H15H14) ¼ 7.3 Hz); 1.19 (dd, CO2CH2Me, 3J(CH2Me) ¼
7.3, 3.9); 1.15 (dd, CO2CH2Me, 3J(CH2Me) ¼ 6.8, 3.9). 31P-
{1H} NMR: 11.20 (d, PA , 2J(PAPB) ¼ 53.4 Hz); ꢀ9.26 (d, PB).
Compounds 6–8 were prepared as white solids in a similar
manner to 4, but using methyl acetoacetate (6), ethyl propiony-
lacetate (7) and ethyl acetoacetate (8) as appropriate.
=
sion of diethyl ether. Yield: > 95%. IR: n(C N): 1579 s. FAB-
MS: 748 [M]+. H NMR: 8.45 (d, Hi, J(PHi) ¼ 8.3 Hz); 6.36
1
4
4
=
(m, C CH2); 6.11 (d, H3 , J(H3H5) ¼ 2.0 Hz); 5.94 (m, H5);
3.81 (s, 2-OMe); 3.25 (s, 4-OMe). 31P-{1H} NMR: 12.75 (d,
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2
CH(COMe)(COOMe)-P,P0}](PF6), 6. Yield: 90%. IR:
PA , J(PAPB) ¼ 16.9 Hz); ꢀ4.05 (d, PB). 13C NMR: 170.9 (t,
2
C N, 3J(PC ¼ 3.5 Hz); 165.0 (dd, C6 , 2J(PtransC6) ¼ 122.8
=
=
=
n(C O): 1720 s, 1741 s; n(C N): 1579 s. FAB-MS: 864
[M]+, 537 [Pd(L)(PPh2)]+, 291 [Pd(PPh2)]+. 1H NMR: 8.43
(d, Hi, 4J(PHi) ¼ 7.8 Hz); 6.06 (d, H3 , 4J(H3H5) ¼ 1.0 Hz);
5.69, 5.64 (m, H5); 4.69 (m, PCHP); 3.79 (s, 2-OMe); 3.67,
3.62 (s, CO2Me); 3.20, 3.18 (s, 4-OMe); 1.97, 1.80 (s, COMe).
31P-{1H} NMR: 12.36, 11.70 (d, PA , 2J(PAPB) ¼ 54.2, 54.2
Hz); ꢀ7.99, ꢀ9.29 (d, PB).
Hz, 2J(PcisC6) ¼ 5.0 Hz); 163.7 (dd, C4 , 4J(PtransC4) ¼ 13.5
Hz, 4J(PcisC4) 8.5 Hz); 160.3 (d, C2 , 4J(PC2) ¼ 10.6 Hz);
146.6 (dd, C13
Hz); 138.1 (t, C14
,
1J(PtransC13) ¼ 30.2 Hz, 1J(PcisC13) ¼ 20.6
,
2J(PC14) ¼ 5.7 Hz); 128.6 (d, C1 ,
3J(PC1) ¼ 2.1 Hz); 115.7 (dd, C5 , 3J(PtransC5) ¼ 14.2 Hz,
3J(PcisC5) ¼ 2.8 Hz); 95.7 (s, C3); 70.0 (d, C7 , J(PC7) ¼ 4.3
3
Hz); 55.6, 55.2 (s, OMe); 33.8 (s, C8 , C12); 24.9, 24.5 (s, C9–
C11).
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2
CH(COEt)(COOEt)-P,P }](PF6), 7. Yield: 83%. IR: n(C O):
Compound 3 was prepared similarly to compound 2 and iso-
lated as a pale yellow solid, but using sodium perchlorate as
appropiate.
0
=
+
=
1720 s, 1740 s; n(C N): 1579 s. FAB-MS: 892 [M] , 537
[Pd(L)(PPh2)]+, 291 [Pd(PPh2)]+. 1H NMR: 8.43 (d, Hi,
4J(PHi) ¼ 8.8 Hz); 6.06 (d, H3 , 4J(H3H5) ¼ 1.0 Hz); 5.67,
5.63 (m, H5); 4.70 (m, PCHP); 4.12 (m, CO2CH2); 3.79 (s, 2-
OMe); 3.21, 3.18 (s, 4-OMe); 1.20 (dd, CO2CH2Me,
=
=
0 Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2C CH2-P,
=
P }](ClO4), 3. Yield: > 95%. IR: n(C N): 1575 s. FAB-MS:
748 [M]+. H NMR: 8.45 (d, Hi, J(PHi) ¼ 8.3 Hz); 6.35 (m,
1
4
3J(CH2Me) ¼ 7.3, 4.4); 1.16 (dd, CO2CH2Me, J(CH2Me) ¼
3
C CH2); 6.10 (d, H3 , 4J(H3H5) ¼ 2.0 Hz); 5.94 (m, H5);
=
6.8, 4.4); 0.87 (m, COCH2Me). 31P-{1H} NMR: 11.95, 11.68
3.81 (s, 2-OMe); 3.25 (s, 4-OMe). 31P-{1H} NMR: 12.58 (d,
2
(d, PA , J(PAPB) ¼ 54.3, 55.1 Hz); ꢀ8.11, ꢀ9.51 (d, PB).
2
PA , J(PAPB) ¼ 16.1 Hz); ꢀ4.27 (d, PB).
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
0
=
CH(COMe)(COOEt)-P,P }](PF6), 8. Yield: 87%. IR: n(C O):
CH(COMe)2-P,P0}](PF6),
4.
N(Cy)-C6,N}{(Ph2P)2 CH2-P,P }](PF6),
Pd{2,4-(MeO)2C6H2C(H)
2 (50 mg, 0.056
=
+
=
1720 s, 1740 s; n(C N): 1579 s. FAB-MS: 878 [M] , 632
0
=
[M ꢀ L]+, 537 [Pd(L)(PPh2)]+, 291 [Pd(PPh2)]+. 1H NMR:
8.43 (d, Hi, 4J(PHi) ¼ 8.8 Hz); 6.06 (d, H3 , 4J(H3H5) ¼ 1.5
Hz); 5.68, 5.64 (m, H5); 4.70 (m, PCHP); 4.13 (m, CO2CH2);
3.79 (s, 2-OMe); 3.21, 3.18 (s, 4-OMe); 1.95, 1.81 (s, COMe);
1.21 (dd, CO2CH2Me, 3J(CH2Me) ¼ 7.3, 3.9); 1.17 (dd,
CO2CH2Me, 3J(CH2Me) ¼ 6.8, 3.9). 31P-{1H} NMR: 11.85,
11.80 (d, PA , 2J(PAPB) ¼ 53.4, 54.2 Hz); ꢀ7.89, ꢀ9.01 (d, PB).
mmol) and acetylacetone (11 mL, 0.112 mmol) were heated at
45 ꢁC in dry chloroform (ca. 5 mL) for 2 hours under Ar in
the presence of anhydrous sodium carbonate (catalytic
amount). The solution was cooled to room temperature, fil-
tered through Celite, and the solvent removed under reduced
pressure to give an oily product. The residue was triturated
with diethyl ether, filtered off, washed with cold diethyl ether
and dried in vacuo to yield the desired product as a yellow
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
=
=
solid. Yield: 95%. IR: n(C O): 1705 s, 1725 s; n(C N): 1578
s. FAB-MS: 848 [M]+, 537 [Pd(L)(PPh2)]+, 291 [Pd(PPh2)]+.
1H NMR: 8.43 (d, Hi, 4J(PHi) ¼ 7.8 Hz); 6.04 (d, H3 ,
4J(H3H5) ¼ 2.0 Hz); 5.67 (m, H5); 4.69 (m, PCHP); 3.94 (t,
CH(COCH2Cl)(COOMe)-P,P0}](PF6), 9. This was prepared
by treating a mixture of 2 and methyl 4-chloroacetoacetate
similarly to 4, except that a reaction time of 4 hours was used.
H15
,
3J(H15H14) ¼ 6.8 Hz); 3.78 (s, 2-OMe); 3.14 (s, 4-
=
=
Yield: 54%. IR: n(C O): 1729 s; n(C N): 1577 s. FAB-MS:
898 [M]+, 862 [M ꢀ HCl]+, 431 [M ꢀ HCl]2+. H NMR: 8.43
1
OMe); 1.94 s, 1.85 (s, COMe). 31P-{1H} NMR: 12.36 (d, PA ,
(d, Hi, 4J(PHi) ¼ 8.3 Hz); 6.04 (d, H3 , 4J(H3H5) ¼ 1.5 Hz);
5.64 (m, H5); 4.65 (m, PCHP); 3.78 (s, 2-OMe); 3.18, 3.14 (s,
4-OMe); 3.69, 3.63 (s, CO2Me), 2.30 (b, CH2Cl). 31P-{1H}
NMR: 12.86, 12.39 (d, PA , 2J(PAPB) ¼ 54.3, 55.9 Hz);
ꢀ7.31, ꢀ8.87 (d, PB).
2J(PAPB) ¼ 55.1 Hz); ꢀ8.66 (d, PB). 13C NMR: 203.3, 203.1
3
=
(s, COMe); 171.0 (t, C N, J(PC) ¼ 3.5 Hz); 166.1 (dd, C6 ,
2J(PtransC6) ¼ 125.6 Hz, 2J(PcisC6) ¼ 8.5 Hz); 163.7 (dd, C4 ,
4J(PtransC4) ¼ 13.5 Hz, 4J(PcisC4) ¼ 8.5 Hz); 160.1 (d, C2 ,
4J(PC2) ¼ 10.6 Hz); 128.6 (d, C1 , 3J(PC1) ¼ 2.0 Hz); 114.3
3
3
Compounds 10 and 11 were prepared analogously to 4 by
treatment of 2 with 1,1,1-trifluoroacetylacetone (10) and the-
noyltrifluoroacetone (11), and isolated as white and yellow
solids, respectively.
(dd, C5 , J(PtransC5) ¼ 13.5 Hz, J(PcisC5) ¼ 3.5 Hz); 95.9 (s,
C3); 69.1 (d, C7 , 3J(PC7) ¼ 4.3 Hz); 64.1 (t, C15
,
,
3J(PC15) ¼ 4.3 Hz); 55.5, 55.1 (s, OMe); 50.7 (dd, C13
1J(PtransC13) ¼ 22.7 Hz, J(PcisC13) ¼ 16.3 Hz); 33.8, 33.3 (s,
1
C8 , C12); 29.7, 29.6 (s, COMe); 26.9 (t, C14
Hz); 25.0, 24.9, 24.6 (s, C9–C11).
,
2J(PC14) ¼ 4.9
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
0
=
CH(COMe)(COCF3)-P,P }](PF6), 10. Yield: 88%. IR: n(C O):
+
=
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
CH(COOEt)2-P,P0}](PF6), 5. A mixture of 2 (0.025 g, .028
mmol) and diethylmalonate (9 mL, 0.056 mmol) was treated
in a similar fashion to the above complex. The final residue
was shown to consist of a 7:3 mixture (as calculated from
1720 s; n(C N): 1579 s. FAB-MS: 806 [MH ꢀ CF3CO] , 537
[Pd(L)(PPh2)]+, 291, [Pd(PPh2)]+. 1H NMR: 8.43 (d, Hi,
4J(PHi) ¼ 8.3 Hz); 6.05 (d, H3 , 4J(H3H5) ¼ 2.0 Hz); 5.70
(m, H5); 4.96 (m, PCHP); 3.78 (s, 2-OMe); 3.17 (s, 4-OMe);
2.45 (t, H15
,
3J(H15H14) ¼ 6.3 Hz); 1.74 (b, COMe).
1430
New J. Chem., 2002, 26, 1425–1432

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31P-{1H} NMR: 11.40 (d, PA , 2J(PAPB) ¼ 53.4 Hz); ꢀ8.90 (d,
PB). 19F NMR: ꢀ71.47 (s, CF3), ꢀ75.23 (s, CF3).
4J(PHi) ¼ 8.3 Hz); 6.02 (d, H3 , 4J(H3H5) ¼ 2.0 Hz); 5.58
(m, H5); 3.75 (s, 2-OMe); 3.20 (s, 4-OMe); 3.44, 3.40 (s,
CO2Me); 2.12, 2.05 (s, COMe). 31P-{1H} NMR: 28.39, 27.54
2
(d, PA , J(PAPB) ¼ 30.5, 30.5 Hz); 12.56, 10.98 (d, PB). 13C
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
CH(COCF3)(CO{2-SC4H3})-P,P0}](PF6), 11. Yield: 80%. IR:
=
NMR: 199.0, 198.8 (s, COMe); 171.5 (m, C N); 169.0 (m,
+
=
=
n(C O): 1740 s; n(C N): 1579 s. FAB-MS: 970 [M] , 874
[MH ꢀ CF3CO]+, 748 [Pd(L)(vdpp)]+, 537 [Pd(L)(PPh2)]+,
291 [Pd(PPh2)]+. 1H NMR: 8.43 (d, Hi, 4J(PHi) ¼ 7.8 Hz);
6.04 (d, H3 , 4J(H3H5) ¼ 2.0 Hz); 5.71 (m, H5); 5.17 (m,
C6); 166.2 (s, COOMe); 163.8 (m, C4); 160.0 (d, C2 ,
4J(PC2) ¼ 9.9 Hz); 114.2 (dd, C5 , 3J(PtransC5) ¼ 11.2 Hz,
3J(PcisC5) ¼ 4.2 Hz); 95.7 (s, C3); 67.7 (b, C7); 50.9 (s, C15);
44.2 (m, C13); 34.0, 33.9, 33.7, 33.4 (s, C8 , C12); 30.5, 29.9 (s,
COMe); 29.2 (b, C14); 25.4, 25.3, 24.8 (b, C9–C11); 55.4, 55.1,
55.0, 53.6 (s, OMe, COOMe)
PCHP); 3.78 (s, 2-OMe); 3.14 (s, 4-OMe); 2.96 (t, H15
,
3J(H15H14) ¼ 6.4 Hz). 31P-{1H} NMR: 12.18 (d, PA ,
2J(PAPB) ¼ 52.6 Hz); –7.69 (d, PB). 19F NMR: ꢀ71.29 (s,
CF3), ꢀ75.07 (s, CF3).
Compounds 12–15 were synthesized similarly, using 1-(2-
furyl)-1,3-butanedione (12), ethyl 2-methylacetoacetate (13),
3-chloroacetylacetone (14) and methyl 2-chloroacetoacetate
(15) as appropriate, and isolated as white solids.
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
CH(COOEt)2-P,P0}](ClO4), 16. Treatment of 0 Pd{2,4-
=
=
(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2 CH2-P,P }](ClO4),
3, with diethylmalonate analogously to 4, but using a reaction
time of 15 hours afforded the desired addition product in pure
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
=
form as a white solid. Yield: 77%. IR: n(C O): 1743 s, 1730 s;
CH(COMe)(CO{2-OC4H3})-P,P0}](PF6), 12. Yield: 77%. IR:
+
+ 1
=
n(C N): 1577 s. FAB-MS: 908 [M] , 748 [Pd(L)(vdpp)] . H
NMR: 8.43 (d, Hi, 4J(PHi) ¼ 8.3 Hz); 6.08 (d, H3 ,
4J(H3H5) ¼ 2.0 Hz); 5.66 (m, H5); 4.82 (m, PCHP); 4.11 (m,
+
=
=
n(C O): 1720 s; n(C N): 1576 s. FAB-MS: 900 [M] , 537
[Pd(L)(PPh2)]+, 291 [Pd(PPh2)]+. 1H NMR: 8.41 (d, Hi,
4J(PHi) ¼ 7.8 Hz); 7.16 (d, Hb , 3J(HbHc) ¼ 3.4 Hz); 6.54
(dd, Hc , 3J(HcHd) ¼ 1.5 Hz); 6.03 (d, H3 , 4J(H3H5) ¼ 2.0
Hz); 5.63 (m, H5); 4.80 (m, PCHP); 4.30 (m, H15); 3.77 (s, 2-
OMe); 3.15 (s, 4-OMe); 2.01, 1.90 (s, COMe). 31P-{1H}
NMR: 13.38, 12,83 (d, PA , 2J(PAPB) ¼ 53.4, 55.1 Hz);
ꢀ6.74, ꢀ7.60 (d, PB). 13C NMR: 201.6 (s, COMe); 182.3 (s,
CO2CH2); 3.79 (s, 2-OMe); 3.24 (s, 4-OMe); 3.02 (t, H15
,
3J(H14H15) ¼ 7.3 Hz); 1.19 (dd, CO2CH2Me, 3J(CH2Me) ¼
7.3, 3.9); 1.15 (dd, CO2CH2Me, 3J(CH2Me) ¼ 6.8, 3.9). 31P-
{1H} NMR: 11.10 (d, PA , 2J(PAPB) ¼ 53.4 Hz); ꢀ9.25 (d, PB).
COfuryl); 170.8 (d, C N, 3J(PC) ¼ 5.7 Hz); 164.0 (m, C4);
=
4
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
160.0 (d, C2 , J(PC2) ¼ 10.6 Hz); 150.9, 150.8 (s, Ca); 148.5,
C(Et)(COMe)2-P,P0}](ClO4), 17. Treatment of 3 and 3-ethyla-
cetylacetone in a similar fashion to 16, but using a reaction
time of 20 hours yielded a 1:1 mixture of the desired addition
product 17 and the starting complex 3. It was not possible to
obtain 17 in pure form by either by recrystallization or column
chromatography. Overall yield: 74%, ca. 37% relative to 17.
FAB-MS: 875 [M]+. 1H NMR: 8.44 (d, Hi, 4J(PHi) ¼ 8.3
148.3 (s, Cd); 128.5 (s, C1); 120.7 (b, Cb); 114.2 (b, C5);
113.5, 113.4 (s, Cc); 96.0 (s, C3); 69.2 (s, C7); 59.3 (s, C15);
55.5, 55.2 (s, OMe); 49.0 (m, C13); 33.8, 33.2 (s, C8 , C12);
29.4 (s, COMe); 27.3 (b, C14); 25.0, 24.8, 24.5 (s, C9–C11).
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
C(Me)(COMe)(COOEt)-P,P0}](PF6), 13. Yield: 65%. IR:
4
+
Hz); 6.03 (d, H3 , J(H3H5) ¼ 2.0 Hz); 5.63 (m, H5); 4.46 (m,
=
=
n(C O): 1730 b,m; n(C N): 1579 s. FAB-MS: 892 [M] , 878
[MH ꢀ Me]+, 748 [Pd(L)(vdpp)]+, 537 [Pd(L)(PPh2)]+, 505
[Pd(L)(PPh2) ꢀ MeO]+, 291 [Pd(PPh2)]+. 1H NMR: 8.41 (d,
Hi, 4J(PHi) ¼ 7.8 Hz); 6.04 (d, H3 , 4J(H3H5) ¼ 1.9 Hz);
5.69, 5.65 (m, H5); 4.56 (m, PCHP); 3.78 (s, 2-OMe); 3.72
(m, CO2CH2); 3.20, 3.19 (s, 4-OMe); 1.76, 1.78 (s, COMe);
1.08 (t, CO2CH2Me, 3J(CH2Me) ¼ 7.1 Hz); 1.07 (s, COC-
MeCO). 31P-{1H} NMR: 16.08, 15.54 (d, PA , 2J(PAPB) ¼
61.04, 61.89 Hz); ꢀ4.29, ꢀ4.63 (d, PB).
PCHP); 3.78 (s, 2-OMe); 3.09 (s, 4-OMe); 1.61, 1.58 (s,
2
COMe). 31P-{1H} NMR: 12.36 (d, PA , J(PAPB) ¼ 64.4 Hz);
ꢀ10.04 (d, PB).
X-Ray crystallographic study
Three-dimensional, room temperature X-ray data were col-
lected on a Siemens Smart CCD diffractometer by the o scan
method using graphite-monochromated Mo-Ka radiation. All
the measured reflections were corrected for Lorentz and polar-
isation effects and for absorption by semi-empirical methods
based on symmetry-equivalent and repeated reflections. The
structures were solved by direct methods and refined by full
matrix least squares on F2. The F1, F2, F4 and F5 fluorine
atoms of the hexafluorophosphate counterion in compound 7
were found to be disordered over two positions (48 and 52%
occupancy). The refinement was carried out taking into
account the minor components of the disorder. The C21 and
C23 carbon atoms of compound 7 showed high displacement
parameters, probably indicating partial disorder, however we
could not find a reasonable model for it. Hydrogen atoms were
included in calculated positions and refined in riding mode.
Refinement converged at a final R ¼ 0.0688 and 0.0550 (for
complexes 2 and 7, respectively, observed data, F) and
wR2 ¼ 0.2027 and 0.1854 (for complexes 2 and 7, respectively,
unique data, F2), with allowance for thermal anisotropy of all
non-hydrogen atoms. The structure solution and refinement
were carried out using the program package SHELX-97.40
CCDC reference numbers 190097 and 190098. See http://
www.rsc.org/suppdata/nj/b2/b203864a/ for crystallographic
data in CIF or other electronic format.
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
0
=
C(Cl)(COMe)2-P,P }](PF6), 14. Yield: 85%. IR: n(C O): 1705
+
+
=
s; n(C N): 1579 s. FAB-MS: 882 [M] , 846 [M ꢀ HCl] , 537
[Pd(L)(PPh2)]+, 291 [Pd(PPh2)]+. 1H NMR: 8.39 (d, Hi,
4J(PHi) ¼ 8.8 Hz); 6.03 (d, H3 , 4J(H3H5) ¼ 2.0 Hz); 5.65
(m, H5); 3.77 (s, 2-OMe); 3.14 (s, 4-OMe); 2.30 (m, CH2CCl);
1.97, 1.80 (s, COMe). 31P-{1H} NMR: 31.3 (d, PA ,
2J(PAPB) ¼ 28.8 Hz); 15.8 (d, PB). 13C NMR: 200.6, (d,
COMe, 4J(PC) ¼ 3.5 Hz); 200.3 (d, COMe, 4J(PC) ¼ 2.8
Hz); 171.4 (t, C N, 3J(PC) ¼ 5.0 Hz); 168.5 (dd, C6 ,
=
2J(PtransC6) ¼ 124.2 Hz, J(PcisC6) ¼ 8.5 Hz); 163.6 (dd, C4 ,
2
4J(PtransC4) ¼ 13.5 Hz, 4J(PcisC4) ¼ 8.5 Hz); 160.0 (d, C2 ,
4J(PC2) ¼ 10.0 Hz); 129.0 (s, C1); 114.4 (dd, C5 ,
3J(PtransC5) ¼ 10.6 Hz, 3J(PcisC5) ¼ 3.5 Hz); 95.8 (s, C3);
67.7 (d, C7 , 3J(PC7) ¼ 5.7 Hz); 57.6 (t, C15
,
3J(PC15) ¼ 2.8
Hz); 55.4, 54.9 (s, OMe); 43.5 (dd, C13
,
1J(PtransC13) ¼ 17.8
Hz, 1J(PcisC13) ¼ 3.5 Hz); 33.9, 33.6 (s, C8 , C12); 30.2, 29.8
(s, COMe); 26.5 (b, C14); 25.4, 25.2, 24.9 (s, C9–C11).
=
[Pd{2,4-(MeO)2C6H2C(H) N(Cy)-C6,N}{(Ph2P)2CHCH2-
C(Cl)(COCH3)(COOMe)-P,P0}](PF6), 15. Yield: 58%. IR:
=
=
n(C O): 1730 s,1704 s; n(C N): 1577 s. FAB-MS: 862
[M ꢀ HCl]+, 748 [Pd(L)(vdpp)]+. 1H NMR: 8.38 (d, Hi,
New J. Chem., 2002, 26, 1425–1432
1431

View Article Online
16 C. Navarro-Ranninger, I. Lopez-Solera, V. M. Gonzalez, J. M.
Perez, A. Alvarez-Valdes, A. Martin, P. Raithby, J. R. Masaguer
and C. Alonso, Inorg. Chem., 1996, 35, 5181.
17 M. Marcos, in Metallomesogens. Synthesis, Properties and Appli-
cations, ed. J. L. Serrano, VCH, Weinheim, 1996.
Acknowledgements
We thank the DGES (Proyecto PB98-0638-C02-01/02) for
financial support. RM acknowledges a fellowship from the
´
Ministerio de Ciencia y Tecnologıa (Spain).
´
18 (a) A. Fernandez, D. Vazquez-Garcıa, J. J. Fernandez, M. Lopez-
Torres, A. Suarez, S. Castro-Juiz and J. M. Vila, New. J. Chem.,
´
´
´
´
´
in press; (b) J. M. Vila, M. T. Pereira, J. M. Ortigueira, M. Gran˜a,
´
´
´
´
D. Lata, A. Suarez, J. J. Fernandez, A. Fernandez, M. Lopez-
Torres and H. Adams, J. Chem. Soc., Dalton Trans., 1999,
4193; (c) A. Ferna´ndez, P. Ur´ıa, J. J. Ferna´ndez, M. Lo´pez-
´
Torres, A. Suarez, D. Vazquez-Garcıa, M. T. Pereira and J. M.
Vila, J. Organomet. Chem., 2001, 620, 8.
´
´
References
´
19 (a) J. M. Vila, M. T. Pereira, J. M. Ortigueira, J. J. Fernandez,
1
(a) C. A. Tolman, Chem. Rev., 1977, 77, 313; (b) C. A. McAuliffe
and W. Levason, Phosphine, Arsine and Stibine Complexes of the
Transition Elements, Elsevier, Amsterdam, 1979; (c) D. W. Meek,
in Homogeneus Catalysis with Metal Phosphine Complexes, ed.
L. H. Pignolet, Plenum Press, New York, 1983; (d ) B. Chaudret,
B. Delavaux and R. Poilblanc, Coord. Chem. Rev., 1988, 86, 191;
(e) O. Stelzer, K. P. Langhans, in The Chemistry of Organopho-
sphorus Compounds, ed. F. R. Hartley, John Wiley, New York,
1990; ( f ) F. A. Cotton and B. Hong, Prog. Inorg. Chem., 1992,
40, 179.
´
A. Fernandez, M. Lopez-Torres and H. Adams, Organometallics,
1999, 18, 5487; (b) M. Lopez-Torres, A. Fernandez, J. J. Fernan-
´
´
´
´
´
dez, A. Suarez, M. T. Pereira, S. Castro-Juiz and J. M. Vila, Orga-
nometallics, 2001, 20, 1350.
´
´
´
20 M. Lousame, A. Fernandez, M. Lopez-Torres, D. Vazquez-Gar-
cıa, J. M. Vila, A. Suarez, J. M. Ortigueira and J. J. Fernandez,
´
´
´
Eur. J. Inorg. Chem., 2000, 2055.
21 J. M. Vila, E. Gayoso, M. T. Pereira, M. Marin˜o, J. Martınez,
´
J. J. Fernandez, A. Fernandez and M. Lopez-Torres, J. Organo-
´
met. Chem., 2001, 637–639, 577.
´
´
2
3
(a) S. Al-Jibori and B. L. Shaw, Inorg. Chim. Acta, 1982, 65, L123;
(b) S. Al-Jibori, M. Hall, A. T. Hutton and B. L. Shaw, J. Chem.
Soc., Dalton Trans., 1984, 863; (c) J. Ruiz, V. Riera, M. Vivanco,
M. Lanfranchi and A. Tiripicchio, Organometallics, 1998, 17,
´
´
22 B. Teijido, R. Mosteiro, A. Fernandez, M. Lopez-Torres, A.
Suarez, J. M. Vila and J. J. Fernandez, Organometallics, 2002,
´
´
21, 1304.
´ ´
23 R. Mosteiro, E. Perille, A. Fernandez, M. Lopez-Torres, J. M.
´
3835; (d ) J. Ruiz, V. Riera, M. Vivanco, S. Garcıa-Granda and
´
´
Vila, A. Suarez, J. M. Ortigueira, M. T. Pereira and J. J. Fernan-
dez, Appl. Organomet. Chem., 2000, 14, 634.
´
M. R. Dıaz, Organometallics, 1998, 17, 4562.
(a) J. L. Bookham, W. McFarlane and I. J. Colquhoun, J. Chem.
Soc., Chem. Commun., 1986, 1041; (b) J. L. Bookham and W.
McFarlane, Polyhedron, 1988, 7, 129; (c) J. L. Bookham, W.
McFarlane and M. Thornton-Pett, J. Chem. Soc., Dalton Trans.,
1992, 2353; (d ) H. Brunner and S. Limmer, J. Organomet. Chem.,
1991, 413, 55.
24 H. Onoue and I. Moritani, J. Organomet. Chem., 1972, 43, 431.
25 Y. Ustynyuk, V. A. Chertov and J. V. Barinov, J. Organomet.
Chem., 1971, 29, C53.
26 M. T. Pereira, J. M. Vila, E. Gayoso, M. Gayoso, W. Hiller and
J. Stra¨hle, J. Coord. Chem., 1988, 18, 245.
4
5
(a) H. Schmidbaur, R. Herr and J. Riede, Angew. Chem., Int. Ed.
Engl., 1984, 23, 247; (b) H. Schmidbaur, R. Herr, G. Muller and
27 L. Tusek-Bozic, M. Curic and P. Traldi, Inorg. Chim. Acta, 1997,
254, 49.
28 W. J. Geary, Coord. Chem. Rev., 1971, 7, 81.
¨
J. Riede, Organometallics, 1985, 4, 1208; (c) H. Schmidbaur, R.
´ ´
29 J. M. Vila, M. Gayoso, M. Lopez Torres, J. J. Fernandez, A.
Herr, T. Pollock, A. Schier, G. Muller and J. Riede, Chem.
Ber., 1985, 118, 3105.
¨
´
Fernandez, J. M. Ortigueira, N. A. Bailey and H. Adams, J. Orga-
(a) A. M. Herring, S. H. Koskimies and B. L. Shaw, J. Organo-
met. Chem., 1988, 338, 13; (b) F. S. M. Hassan, B. L. Shaw and
M. Thornton-Pett, J. Chem. Soc., Dalton Trans., 1988, 89.
P. A. Dolby, M. M. Harding, N. Newar and A. K. Smith, J.
Chem. Soc., Dalton Trans., 1992, 2939.
(a) N. Nawar and A. K. Smith, J. Organomet. Chem., 1995, 493,
239; (b) J. V. Barkley, S. J. Higgins, M. K. McCart and T. J.
Pounds, Inorg. Chem., 1997, 36, 6188.
nomet. Chem., 1996, 511, 129.
30 P. S. Pregosin and R. W. Kuntz, 31P and 13C NMR of Transition
Metal Phosphine Complexes, vol. 16 in NMR Basic Principles and
Progress, eds. P. Diehl, E. Fluck and R. Kosfeld, Springer, Berlin,
1979.
6
7
´
31 (a) J. Granell, D. Sainz, J. Sales, X. Solans and and M. Font-
Altaba, J. Chem. Soc., Dalton Trans., 1986, 1785; (b) J. M. Vila,
´
´
´
M. Gayoso, M. T. Pereira, M. Lopez, G. Alonso and J. J. Fernan-
8
9
(a) F. S. M. Hassan, S. J. Higgins, G. B. Jacobsen, B. L. Shaw and
M. Thornton-Pett, J. Chem. Soc., Dalton Trans., 1988, 3011; (b)
S. J. Higgins and B. L. Shaw, J. Chem. Soc., Dalton Trans.,
1989, 1527; (c) G. King, S. J. Higgins and A. Hopton, J. Chem.
Soc., Dalton Trans., 1992, 3403.
dez, J. Organomet. Chem., 1993, 445, 287.
32 R. T. Morrison and R. K. Boyd, Organic Chemistry, 6th edn.,
Benjamin Cummings, San Francisco, 1992.
33 H. Schmidbaur, R. Herr and J. Riede, Chem. Ber., 1984, 117,
2322.
34 (a) W. L. Steffen and G. J. Palenik, Inorg. Chem., 1976, 15, 2432;
(b) C. L. Lee, Y. P. Yang, S. Rettig, B. R. James, D. A. Nelson
and M. A. Lilga, Organometallics, 1986, 5, 2220.
35 L. Pauling, The Nature of Chemical Bond, 3rd edn., Cornell Uni-
versity Press, New York, 1960.
´
E. J. Fernandez, M. C. Gimeno, P. G. Jones, A. Laguna and
E. Olmos, Organometallics, 1997, 16, 1130.
10 H. Schmidbaur, R. Herr, G. Muller and J. Riede, Organometal-
lics, 1985, 4, 1208.
11 W. Clegg, K. Izod, W. McFarlane and P. O’Shaughnessy, Orga-
nometallics, 1998, 17, 5321.
12 (a) M. Pfeffer, Recl. Trav. Chim. Pays Bas, 1990, 109, 567; (b) J.
Spencer and M. Pfeffer, Adv. Met. Org. Chem., 1994, 3, 103; (c)
I. Omae, Applications of Organometallic Compounds, Wiley &
Sons, Chichester, 1998.
¨
´
36 J. M. Vila, M. T. Pereira, J. M. Ortigueira, M. Lopez-Torres,
A. Castin˜eiras, D. Lata, J. J. Fernandez and A. Fernandez, J.
´
´
Organomet. Chem., 1998, 556, 31.
37 (a) A. Suarez, J. M. Vila, E. Gayoso, M. Gayoso, W. Hiller,
A. Castin˜eiras and J. Stra¨hle, Z. Inorg. Allg. Chem., 1986, 535,
´
213; (b) R. Bosque, C. Lopez, X. Solans and M. Font-Bardia,
Organometallics, 1999, 18, 1267.
´
13 J. Dupont, M. Pfeffer and J. Spencer, Eur. J. Inorg. Chem., 2001,
1917.
14 A. von Zelewski, P. Belser, P. Hayos, R. Dux, X. Hua, A. Suck-
ling and H. Stoeckli-Evans, Coord. Chem. Rev., 1994, 132, 75.
15 (a) S. B. Wild, Coord. Chem. Rev., 1997, 166, 291; (b) W. A. Herr-
mann, C. Brossmer, K. Oefele, C. P. Reisinger, T. Priermeier, M.
Beller and H. Fischer, Angew. Chem., Int. Ed. Engl., 1995, 34,
1844
38 W. L. F. Armarego and D. D. Perrin, Purification of Laboratory
Chemicals, 4th edn., Butterworth-Heinemann, Oxford, 1997.
39 I. J. Colquhoun and W. McFarlane, J. Chem. Soc., Dalton Trans.,
1982, 1915.
40 G. M. Sheldrick, SHELX-97, University of Go¨ttingen, Germany,
1997.
1432
New J. Chem., 2002, 26, 1425–1432