Synthesis, structure and reactivity of PtII complexes containing the [o-(di-o-tolylphosphino)benzyl] cyclometalated ligand towards α-stabilized phosphorus ylides

Article abstract of DOI:10.1016/S0022-328X(98)00550-6

The reaction of [Pt(C^∧P)(NCMe)₂]ClO₄ 2 [C^∧P=ortho-(di-ortho-tolylphosphino)benzyl], with the α-stabilized phosphorus ylides Ph₃P=C(H)R (R=COMe, COPh, COOMe, CN) in a 1:1 molar ratio results in the formation of [Pt(C^∧P){C(H)(R)PPh₃}(NCMe)]ClO₄ (R=COMe 3, COPh 4, COOMe 5, CN 6). Complexes 3-6 appear as single isomers in which the ylide is selectively C-coordinated trans to the P atom of the C^∧P ligand. The displacement of the remaining coordinated NCMe ligand by adding more ylide was only successfully accomplished with Ph₃P=C(H)CN, giving [Pt(C^∧P){C(H)(CN)PPh₃}{NC-C(H)PPh ₃}]ClO₄ 7, in which one ylide is C-coordinated trans to the P atom of the C^∧P ring and the other ylide is N-coordinated trans to the C atom, showing the ambidentate character of Ph₃P=C(H)CN as a ligand. The reaction of [Pt(C^∧P)(μ-Cl)]₂ 1 with PPh₃ (1:2 molar ratio, CH₂Cl₂, r.t.) results in the formation of the two expected isomers trans- and cis-[Pt(C^∧P)Cl(PPh₃)] (8 and 9, respectively). The trans isomer 8 is obtained as a single product by heating the mixture of isomers in toluene or, in one step, by carrying out the reaction of 1 with PPh₃ in refluxing toluene. Treatment of 8 with TlClO₄ in NCMe gives trans-[Pt(C^∧P)(PPh₃)(NCMe)]ClO₄ 10 which can also be obtained by the reaction of 2 with PPh₃. Complex 10 reacts with Ph₃P=C(H)R (R=COMe, COOMe, CN) in a 1:1 molar ratio resulting in the displacement of the NCMe ligand and the formation of [Pt(C^∧P){OC(R′)=C(H)PPh₃}PPh ₃]ClO₄ (R′=Me 11, OMe 12) or [Pt(C^∧P){NC-C(H)=PPh₃}PPh₃]ClO₄ 13 in which the ylide ligand is selectively O- (11, 12) or N-coordinated (13). The reaction of [Pt(C^∧P)(μ-Cl)]₂ 1 with Ph₃P=C(H)R (R=COMe, COOMe, CN) in a 1:2 molar ratio results in the cleavage of the chlorine-bridge system and the formation of [Pt(C^∧P)Cl{C(H)(R)PPh₃}] (R=COMe 14, COOMe 15, CN 16) as single isomers in which the ylide is C-coordinated trans to the P atom of the C^∧P ligand. Complex 14 reacts with TlClO₄ and Ph₃P=C(H)COMe (1:1:1 molar ratio) giving [Pt(C^∧P){OC(Me)=C(H)PPh₃}₂]ClO₄ 17. Complex 17 shows two interesting features: the isomerization of the C-linked ylide in 14 to an O-bonded one in 17 and the simultaneous presence of two O-coordinated ylides to the same metal center. The selectivity in the observed coordination modes and the preferred coordination of the ylides trans to the P atom of the C^∧P ligand are discussed in terms of electronic and steric factors.

Full text of DOI:10.1016/S0022-328X(98)00550-6

Journal of Organometallic Chemistry 561 (1998) 67–76
Synthesis, structure and reactivity of PtII complexes containing the
[o-(di-o-tolylphosphino)benzyl] cyclometalated ligand towards
h-stabilized phosphorus ylides
Susana Ferna´ndez, Mar´ıa M. Garc´ıa, Rafael Navarro *, Esteban P. Urriolabeitia
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Uni6ersidad de Zaragoza-Consejo Superior de In6estigaciones Cient´ıficas, 50009 Zaragoza, Spain
Received 10 November 1997
Abstract
‚
‚
The reaction of [Pt(C P)(NCMe)2]ClO4 2 [C P=ortho-(di-ortho-tolylphosphino)benzyl], with the h-stabilized phosphorus
1:1 molar ratio results in the formation of
ylides Ph3PꢀC(H)R (R=COMe, COPh, COOMe, CN) in
a
‚
[Pt(C P){C(H)(R)PPh3}(NCMe)]ClO4 (R=COMe 3, COPh 4, COOMe 5, CN 6). Complexes 3–6 appear as single isomers in
‚
which the ylide is selectively C-coordinated trans to the P atom of the C P ligand. The displacement of the remaining coordinated
NCMe ligand by adding more ylide was only successfully accomplished with Ph3PꢀC(H)CN, giving
‚
‚
[Pt(C P){C(H)(CN)PPh3}{NC–C(H)PPh3}]ClO4 7, in which one ylide is C-coordinated trans to the P atom of the C P ring and
the other ylide is N-coordinated trans to the C atom, showing the ambidentate character of Ph3PꢀC(H)CN as a ligand. The
‚
reaction of [Pt(C P)(v-Cl)]2 1 with PPh3 (1:2 molar ratio, CH2Cl2, r.t.) results in the formation of the two expected isomers trans-
and cis-[Pt(C P)Cl(PPh3)] (8 and 9, respectively). The trans isomer 8 is obtained as a single product by heating the mixture of
‚
isomers in toluene or, in one step, by carrying out the reaction of 1 with PPh3 in refluxing toluene. Treatment of 8 with TlClO4
‚
in NCMe gives trans-[Pt(C P)(PPh3)(NCMe)]ClO4 10 which can also be obtained by the reaction of 2 with PPh3. Complex 10
reacts with Ph3PꢀC(H)R (R=COMe, COOMe, CN) in a 1:1 molar ratio resulting in the displacement of the NCMe ligand and
‚
‚
the formation of [Pt(C P){OC(R%)=C(H)PPh3}PPh3]ClO4 (R%=Me 11, OMe 12) or [Pt(C P){NC–C(H)ꢀPPh3}PPh3]ClO4 13 in
‚
which the ylide ligand is selectively O- (11, 12) or N-coordinated (13). The reaction of [Pt(C P)(v-Cl)]2 1 with Ph3PꢀC(H)R
(R=COMe, COOMe, CN) in a 1:2 molar ratio results in the cleavage of the chlorine-bridge system and the formation of
[Pt(C P)Cl{C(H)(R)PPh3}] (R=COMe 14, COOMe 15, CN 16) as single isomers in which the ylide is C-coordinated trans to
‚
‚
the P atom of the C P ligand. Complex 14 reacts with TlClO4 and Ph3PꢀC(H)COMe (1:1:1 molar ratio) giving
‚
[Pt(C P){OC(Me)ꢀC(H)PPh3}2]ClO4 17. Complex 17 shows two interesting features: the isomerization of the C-linked ylide in 14
to an O-bonded one in 17 and the simultaneous presence of two O-coordinated ylides to the same metal center. The selectivity
‚
in the observed coordination modes and the preferred coordination of the ylides trans to the P atom of the C P ligand are
discussed in terms of electronic and steric factors. © 1998 Elsevier Science S.A. All rights reserved.
‚
Keywords: Platinum; C P-cyclometalated; Phosphorus ylides
1. Introduction
lized phosphorus ylides Ph3PꢀC(H)R (R=COMe,
COPh, COOMe, CN), due to the fact that these ylides
can behave as ambidentate ligands [1–4]. The main
body of our study comprises the reactivity of the afore-
mentioned ylides Ph3PꢀC(H)R towards C,N-cyclometa-
Over the last few years our research group has been
interested in the coordination chemistry of the h-stabi-
lated
complexes
of
PdII
of
stoichiometry
* Corresponding author. Tel.: +34 76 761296; fax: +34 76
761187.
‚
‚
[Pd(C N)(L)(L%)]ClO4 or [Pd(v-Cl)(C N)]2, where
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00550-6

68
S. Ferna´ndez et al. / Journal of Organometallic Chemistry 561 (1998) 67–76
Fig. 1. Schematic representations of the ligand [o-(di-o-tolylphosphino)benzyl].
‚
C N=(2-(dimethylamino)methyl)phenyl (or dmba) or
S-h-(2-(dimethylamino)ethyl)phenyl (or S-dmphea)
and L=phosphine, phosphite, pyridine, L%=NCMe or
L=L%=NCMe. In these studies [1–4] we have actually
shown the ambidentate character of the h-stabilized
ylides and how it is possible to predict both the coordi-
nation site of the ylide (when there are two possibilities)
and the donor atom linked to the metal (O- versus
C-coordination, N- versus C-coordination) taking into
account a simple effect such as the antisymbiotic be-
haviour of the PdII centre [5,6] and the different elec-
tronic and steric requirements of the ylides in their
different coordination modes.
in the formation of the mono-ylide complexes
[Pt(C P)(Ph3PCHR)(NCMe)]ClO4 (R=COMe 3,
COPh 4, COOMe 5, CN 6), according to their elemen-
tal analyses of C, H, N and mass spectra (see Section
3).
‚
When reactions between 2 and the keto-stabilized
ylides Ph3P=C(H)COR’ are performed in the same
experimental conditions but in a 1:2 molar ratio
(Pt:ylide), the formation of the corresponding bis-ylide
complexes have not been observed, and only the mix-
ture of the mono-ylide complex and the corresponding
free ylide (3 and Ph3P=C(H)COMe, etc) is detected.
The same result is observed if the reaction is performed
in more drastic conditons (CHCl3 reflux) and the pro-
longed treatment of 2 with an excess of ylide in a
solvent with a high boiling point (toluene, reflux) leads
to the decomposition of the mixture and deposition of
black platinum. However, the reaction between 2 and
two equivalents of Ph3PꢀC(H)CN (CH2Cl2, r.t.) results
in the formation of the bis-ylide complex
This previous work has prompted us to extend this
kind of chemistry to other metals and cyclometalated
systems, with the aim of obtaining new structural situa-
tions. We have thus explored the reactivity of the
fragment [Pt(C P)] [7,8] [C P=ortho-(di-ortho-
tolylphosphino)benzyl] (see Fig. 1) towards h-stabilized
ylides on the grounds that the donor atoms of the
‚
‚
‚
‚
cyclometalated C P ligand show different electronic
and steric properties than those of the ligands C N (we
[Pt(C P)(Ph3PCHCN)2]ClO4 7 according to elemental
‚
analyses and its mass spectrum (see Section 3). This
now have two soft donor atoms with a high trans
influence and, in addition, a highly steric-demanding
P(o-tolyl)2 group). Moreover, the platinum atom re-
veals symbiotic or antisymbiotic behaviour depending
on the ligands that are present in the molecule [5],
although its behaviuor is usually marked by ‘orbital-
controlled’ interactions, i.e. it behaves in an antisymbi-
otic manner [6]. In this paper we report the results
obtained with this kind of chemistry.
behaviour is similar to that we have previously ob-
served [2,3] in C N-cyclometalated derivatives of pal-
ladium (II), except for the synthesis of complex 6 which
has no equivalent in palladium chemistry [2].
‚
The elucidation of the coordination mode of the
ylide(s) and the stereochemistry of the resulting com-
plexes 3–7 can be inferred from the IR and NMR data.
The IR spectra of 3, 4 and 5 show the presence of
absorptions attributed to the coordinated NCMe ligand
(about 2300–2200 cm−1), characteristic absorptions of
‚
the C P group [7] and a strong absorption in the
2. Results and discussion
1700–1600 region attributed to the carbonyl group of
the coordinated ylide. This latter absorption appears to
be shifted to higher energies with respect to that in the
corresponding free ylide [Dw=wCO(complex)−wCO(free
ylide)=112 (3), 100 (4), 65 (5) cm−1] which is indica-
tive of C-coordination [1,3]. The IR spectra of com-
plexes 6 and 7 show a broad absorption in the
2230–2170 cm−1 region, attributed to the CN group of
the coordinated ylide (although for 6 it also contains
the contribution of the NCMe ligand) and also a shift
‚
2.1. Reactions of [Pt(C P)(NCMe)2]ClO4 with ylides
The
synthesis
of
the
starting
product
‚
‚
[Pt(C P)(NCMe)2]ClO4 2 from [Pt(v-Cl)(C P)]2 1 and
AgClO4 (1:2 molar ratio) in NCMe has been previously
described [7]. The reaction of 2 with the stoichiometric
amount of the ylides Ph3PꢀC(H)R (R=COMe, COPh,
COOMe, CN; 1:1 molar ratio) in CH2Cl2 at r.t. results

S. Ferna´ndez et al. / Journal of Organometallic Chemistry 561 (1998) 67–76
69
spectroscopic parameters of the ylidic CH resonance
points to C-coordination of the ylide [3]. Moreover, the
31P{1H}-NMR spectra show the same pattern of reso-
nances for 3–5: a doublet signal (about 27 ppm) with
195Pt satellites (1JPt–P about 3400 Hz) attributed to the
to higher energies with respect to that in the free ylide.
In this case, as has been discussed [2], this shift could
mean that the ylide is either C-bonded (in the usual
way) or N-bonded (end-on nitrile).
The NMR spectra of 3-5 show, at r.t., broad, poorly
resolved resonances. Measurements at low temperatures
(CD2Cl2, 188 K) provide more informative spectra.
‚
P atom of the C P ligand and another doublet, in the
same region, also with 195Pt satellites in 3 (2JPt–P about
78 Hz), attributed to the ylidic phosphorus. The chemi-
cal shift of the P-ylidic resonance and the observation
of a low but observable value for the coupling constant
JPt–P(ylide) are in line with C-coordination, whilst the
shape of the resonances, which are doublets due to the
P–P coupling, indicates a relative trans location of the
1
Thus, the H-NMR spectra of 3–5 show an AB spin
system for the diastereotopic CH2 protons and two
‚
singlet resonances for the methyl groups of the C P
ligand. The ylidic CH proton appears as a doublet for
3 and 4, shifted downfield with respect to that in the
corresponding free ylide, and with a value of the cou-
2
‚
pling constant JP–H of about 11 Hz, notably smaller
C (ylide) and P (C P ligand) atoms. The structure
than that found in the free ylide. The ylidic CH reso-
depicted in Scheme 1 would account for all these facts.
Similar conclusions can be obtained from the NMR
spectra of 6. The CH ylidic proton appears in the
1H-NMR spectrum as a doublet of doublets at 3.93
ppm and shows 195Pt satellites, providing proof of the
nance in 5 appears as a doublet of doublets, probably
‚
by additional coupling with the P atom of the C P
ligand. The disappearance of the molecular plane as a
‚
symmetry plane (reflected in the C P ligand) and the

70
S. Ferna´ndez et al. / Journal of Organometallic Chemistry 561 (1998) 67–76
‚
2.3. Synthesis of trans-[Pt(C P)(PPh3)(NCMe)](ClO4)
(10) and reactions with ylides
C-coordination of the ylide trans to the P atom of the
‚
C P ligand. The 31P{1H}-NMR spectrum of 6 shows
two doublet resonances, each one with 195Pt satellites of
different magnitude. The structure depicted in Scheme 1
for 6 represents the experimental data obtained. The
1H-NMR spectrum of 7 reveals a very similar pattern
of resonances to that of 6, except for the presence of an
The synthesis of 10 was carried out by two alterna-
tive synthetic methods: (a) treatment of trans-[Pt-
Cl(C P)(PPh3)] 8 with TlClO4 (1:1 molar ratio) in
‚
refluxing
NCMe
[Pt(C P)(NCMe)2]ClO4 2 with PPh3 (1:1 molar ratio)
in CH2Cl2 at r.t.. In both cases solid with
and
(b)
treatment
of
‚
2
additional doublet at high field (1.27 ppm, JP–H=4.8
a
Hz) which is assigned to the CH ylidic proton of the
ylide Ph3PꢀC(H)CN N-coordinated [2]. Obviously, this
N-coordination must be produced trans to the C atom
‚
[Pt(C P)(PPh3)(NCMe)](ClO4) (10) stoichiometry was
obtained, according to their analytical data and mass
spectra (see Section 3). The spectral parameters (IR,
NMR) were identical, irrespective of the synthetic
method.
‚
of the C P ligand. Moreover, the 31P{1H}-NMR spec-
trum of 7 shows two doublet resonances about 26 ppm
with 195Pt satellites of different magnitudes, attributed
The IR spectrum confirms the presence of coordi-
‚
to the P atoms of the C P ligand and the C-coordi-
nated NCMe (absorptions at 2317 and 2287 cm−1) and
nated ylide, mutually trans, and a singlet signal at 22.7
ppm attributed to the P atom of the N-bonded ylide [2].
Thus, the structure of 7 shown in Scheme 1 accounts
for these observations and, once again, clearly shows
the ambidentate character (C- versus N-coordination)
of the cyano ylide Ph3PꢀC(H)CN.
1
phosphine ligands. The H-NMR spectrum shows the
presence of all the expected resonances and the
31P{1H}-NMR spectrum shows the presence of an AB
spin system with chemical shifts that are very similar to
those of the starting compound 8, as well as coupling
constant values in keeping with a trans arrangement of
The selectivity in the C-coordination trans to the P
2
the P atoms (1JPt–P=2966.3, 2934.1 Hz; JP–P=383.7
‚
atom of the C P ligand could be related to steric
Hz) [10] (see Scheme 1).
interactions, given that the voluminous C-bonded ylide
would be more stable when coordinated in the less
hindered of the two possible positions in the starting
compound 2, that is, trans to the P atom.
It is noteworthy to point out the selectivity shown in
the displacement of the NCMe ligand trans to the P
atom of the P(o-Tol)2 group. Even if it would seem that
the more labilized position would be that which is trans
to the C atom [7], the steric congestion produced by the
bulky ortho-tolyl substituents appears to be the reason
for the selective coordination trans to the P atom, in
order to minimize steric repulsions. This fact could also
be responsible for the selective C(ylide)-trans-P(tol)2
coordination observed in compounds 3–7 and for the
higher thermodynamic stability of complex 8 with re-
spect to 9.
‚
2.2. Synthesis of trans- and cis-[Pt(C P)Cl(PPh3)] (8,
9)
‚
The reaction of the starting dimer [Pt(v-Cl)(C P)]2 1
with the stoichiometric amount of PPh3 (1:2 molar
ratio) in CH2Cl2 at r.t. produces the gradual dissolution
of the dinuclear complex, giving a colorless solution
‚
from which a white solid of [PtCl(C P)(PPh3)] stoi-
The NCMe ligand present in 10 can easily be re-
placed by other groups and we have tested the reactiv-
ity of 10 towards h-stabilized ylides. The reaction of 10
with the ylides Ph3PꢀC(H)COR (R=Me, Ph, OMe)
and Ph3PꢀC(H)CN (1:1 molar ratio, CH2Cl2, r.t.) re-
sults in the formation of the corresponding cationic
chiometry can be obtained. Two absorptions are ob-
served in the w(Pt–Cl) stretching region [9], suggesting
the presence of two isomers. This fact is confirmed by
the presence in the 31P{1H}-NMR of two AB spin
systems. The major one (4:1 molar ratio) reveals similar
1
‚
values of the coupling constant JPt–P (3126.5, 3047.7
derivatives with [Pt(C P)(PPh3)(Ph3PCHCOR)](ClO4)
2
‚
Hz) and a value of JP–P of 446.6 Hz, both facts
(R=Me 11, OMe 12) and [Pt(C P)(PPh3)(Ph3PCH-
indicating the P-trans-to-P arrangement [10] (complex
CN)](ClO4) 13 stoichiometry, according to their ele-
mental analyses and mass spectra (see Section 3). The
less basic ylide Ph3PꢀC(O)Ph did not yield an apparent
reaction and the mixture of the starting compounds
remained unchanged.
1
8). The minor one reveals very different values of JPt–P
2
(4370.4, 1834.5 Hz) and a value of JPP of 10.3 Hz,
clearly showing a cis arrangement [10,11] of the P
atoms (complex 9), as depicted in Scheme 1.
The selective synthesis of the trans derivative 8 was
carried out either by refluxing the mixture of com-
pounds 8 and 9 in toluene or, alternatively, in one step,
breaking the chlorine bridge with PPh3 in refluxing
toluene (see Section 3). Similar cis–trans isomerization
processes have already been described [12].
The IR spectra of 11 and 12 show the w(CO) absorp-
tion of the ylide ligand shifted to lower energies with
respect to that in the free ylide, suggesting an O-coordi-
nation [1,3] of this ligand. The IR spectrum of 13 shows
the w(CN) absorption shifted to higher energies, which
is in keeping with both C- and N-coordination [2].

S. Ferna´ndez et al. / Journal of Organometallic Chemistry 561 (1998) 67–76
71
ylides Ph3PꢀC(H)COR (R=Me, Ph, OMe) and
Ph3PꢀC(H)CN (1:2 molar ratio) in refluxing CH2Cl2
results in the gradual dissolution of the initial suspen-
sion. From the resulting colorless solution, white solids
The NMR spectra of 11 and 12 are in line with the
O-coordination inferred from their IR spectra. Thus,
1
the H-NMR spectrum of 11 shows two sets of reso-
nances with the same pattern but with a different
intensity (1.44:1 molar ratio), suggesting the presence of
two structural isomers. In both cases the ylidic proton
appears as a doublet, with a value of the coupling
constant 2JP–H of around 20 Hz which is very similar to
that observed in the free ylide [13,14], and points to
O-coordination [1,3]. The two isomers present are due
to the different conformation of the ylide in each
complex, cisoid and transoid (see Scheme 1), the tran-
soid isomer being the more abundant one. Similar
conclusions can be derived from the 1H-NMR spectrum
of 12 although in this case the transoid/cisoid molar
ratio is 3:1. The 31P{1H}-NMR spectrum of 11 shows
the presence of two AB spin systems, each with similar
chemical shifts and coupling constants to those of the
starting product 10, which suggests that the P-trans-P
arrangement is preserved. In addition, two resonances
at 14.01 and 13.38 ppm are attributed to the ylidic P
atom, showing high field shifts compared to the corre-
sponding value in the free ylide, this is also in keeping
with O-coordination [1,3]. The structures depicted in
Scheme 1 are proposed on the basis of these data.
The 1H-NMR spectrum of complex 13 shows a single
set of resonances in which the doublet of triplets cen-
tered at 1.06 ppm (2JP–H=5.2 Hz, 5JP–H=0.9 Hz)
should be noted. This resonance is attributed to the
ylidic CH proton and both the chemical shift and the
‚
of [PtCl(C P)(Ph3PCHCR%)] stoichiometry (R%=
COMe 14, COOMe 15, CN 16) were obtained after the
usual work-up. No reaction was observed for the less
basic ylide Ph3PꢀC(H)COPh, even after prolonged
treatment at the reflux temperature.
The IR spectra of 14 and 15 show that the carbonyl
absorption is shifted to higher energies, thus indicating
the C-coordination of the ylide, as discussed in Section
2.1. The IR spectrum of 16 shows that the w(CN)
stretching mode is shifted to higher energies, in keeping
with both C- and N-coordination modes. Only one
absorption is observed for the w(Pt–Cl) stretching, sug-
gesting that only one isomer is obtained. This w(Pt–Cl)
absorption appears at higher wavenumbers than in the
starting compound 1, in line with the change from the
bridging mode to the terminal mode for the chlorine
ligand.
The NMR spectra confirm C-coordination which, in
all cases, is trans to the P atom of the P(o-tol)2 group.
Thus, the 1H-NMR spectrum of 14 shows a single set of
signals, in keeping with the presence of only one iso-
mer, in which the ylidic CH resonance appears as a
doublet of doublets (2JP–H=8.5 Hz, 3JP–H=3.2 Hz)
flanked by 195Pt satellites (2JPt–H=60 Hz). While the
2
value of JP–H confirms C-coordination, the observa-
3
tion of the coupling constant JP–H means that C-coor-
2
dination has taken place trans to a second P atom (that
of the P(o-tol)2 group). The 31P{1H}-NMR spectrum of
14, however, shows two resonances; a broad singlet at
about 27 ppm with 195Pt satellites (3790 Hz) attributed
coupling constant JP–H are indicative of a N-coordina-
tion of the ylide (end-on nitrile form) [2], as depicted in
Scheme 1. The observation of an AB spin system in the
31P{1H}-NMR spectrum of 13, attributed to the PPh3
‚
‚
to the P atom of the C P ring and a doublet at higher
and the mutually trans C P ligands and a singlet
field (about 25 ppm, 3JP–P=10 Hz) also with 195Pt
satellites (53 Hz) attributed to the P atom of the ylide
ligand. All these facts confirm the proposed structure
which is depicted in Scheme 1. Similar conclusions can
be inferred from the analysis of the NMR spectra of 15
and 16.
resonance at 21.95 ppm shifted only slightly upfield
with respect to the free ylide [15], provide further
arguments in favor of N-coordination.
In these cases, the selectivity in the coordination
modes of the ylides (always using the heteroatom as the
donor atom), seems to be related to steric congestions.
In fact, the vacant position in the starting compound 10
is located between two very bulky groups, the PPh3
ligand and the P(o-tol)2 fragment. Both the O- and the
N-coordination modes are less sterically demanding
than the C-form and, probably due to this fact, the
former two are the preferred coordination modes. This
behaviour is closely related to that observed in C,N-cy-
clometalated ligands [1–3].
As has been discussed, the selective C-trans-to-P-co-
ordination observed seems to be related to steric repul-
sions. However, this behavior is quite different to that
observed with the C,N-cyclometalated complexes [1–3].
In fact, the h-ketostabilized ylides Ph3PꢀC(H)COR
were not nucleophilic enough to produce the breakage
of the bridging chlorine system while in this system 1
reacts slowly giving the corresponding products of the
bridge cleavage. Moreover, the cyano-stabilized ylide
Ph3PꢀC(H)CN produces a mixture of C- and N-coordi-
‚
2.4. Reactions of [Pt(v-Cl)(C P)]2 with ylides
‚
nated ylides after reaction with [Pd(v-Cl)(C N)]2
‚
The reaction of the chlorine bridge dimer [Pt(v-
(C N=dmba, R-dmphea) while, in this case, the C-
‚
Cl)(C P)]2 1 with the stoichiometric amount of the
coordination mode is observed selectively.

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S. Ferna´ndez et al. / Journal of Organometallic Chemistry 561 (1998) 67–76
‚
2.5. Synthesis of [Pt(C P){OC(Me)ꢀC(H)PPh3}2]-
(ClO4) (17)
3. Experimental section
3.1. General comments
Futher reactivity of complexes 14-16 have been
explored.
Treatment
of
complex
14
[Pt-
Solvents were dried and distilled prior to use by
standard methods. Elemental analyses of C, H, N were
carried out on a Perkin-Elmer 2400 microanalyser.
Infrared spectra (4000–200 cm−1) were recorded on a
Perkin-Elmer 883 infrared spectrophotometer in nujol
mulls between polyethylene sheets. 1H (300.13 MHz)
and 31P{1H} (121.49 MHz)-NMR spectra were
recorded from CDCl3, CD2Cl2 or (CD3)2CO solutions
at r.t. (unless otherwise stated) on a Bruker ARX-300
‚
Cl(C P){C(H)PPh3(COMe)}] with the stoichiometric
amounts of TlClO4 and, following this, the filtration
of TlCl, Ph3PꢀC(H)COMe (1:1:1 molar ratio, THF,
r.t.) results in the formation of
a
solid of
‚
[Pt(C P)(PPh3CHCOMe)2](ClO4) stoichiometry (17),
according to elemental anlyses and mass spectrum.
The coordination mode(s) of the ylide is elucidated
the analysis of the IR and NMR spectra. The IR
spectrum of 17 shows a strong absorption, attributed to
the carbonyl groups, at 1505 cm−1, thus clearly point-
ing to a shift to lower energies than those in the free
ylide and indicating the O-coordination of the ylide.
1
spectrometer; H-NMR spectra were referenced using
the solvent signal as an internal standard and 31P{1H}-
NMR spectra were externally referenced to H3PO4
(85%). Mass spectra (positive ion FAB) were recorded
on a V.G. Autospec. spectrometer from CH2Cl2 solu-
1
The H-NMR spectrum shows, in addition to the ex-
‚
‚
pected resonances for the C P ligand, two resonances
tions. The starting materials [Pt(v-Cl)(C P)]2 1,
‚
of relative intensity 1:1 at 4.33 and 3.87 ppm, attributed
to the ylidic CH protons. The signal centered at 4.33
shows a doublet of doublets structure (2JP–H=24 Hz,
[Pt(C P)(NCMe)2]ClO4 2 [7], Ph3PꢀC(H)COR (R=
Me, Ph, OMe) [13,14] and Ph3PꢀC(H)CN [15] were
prepared according to published methods.
5JP–H=2.3 Hz). The value of JP–H clearly shows the
2
5
‚
O-coordination and the value of JP–H its coordination
trans to the P atom of the C P ring. The signal
3.2. Synthesis of [Pt(C P){C(H)(COMe)(PPh3)}-
‚
(NCMe)]ClO4 3
centered at 3.87 ppm is a doublet with a coupling
‚
constant value of 2JP–H=23 Hz, also indicating the
To a solution of [Pt(C P)(NCMe)2]ClO4 2 (0.200 g,
‚
O-coordination trans to the C atom of the C P ligand.
0.294 mmol) in 20 ml of CH2Cl2 the ylide
Ph3PꢀC(H)COMe (0.093 g, 0.294 mmol) was added and
the resulting solution was stirred at r.t. for 10 min. The
solvent was then evaporated to dryness and the residue
was washed with Et2O (25 ml) giving 3 as a white solid
which was collected and air dried. Obtained: 0.242 g
(86% yield). Complex 3 was recrystallized from CH2Cl2/
n-hexane, giving poor, colorless, crystals of
3.0.5CH2Cl2, which were used for analytical and NMR
measurements (the amount of CH2Cl2 was quoted from
Both O-coordinated ylide ligands have a cisoid confor-
mation, as can be inferred from the shape of the COMe
resonance, doublet due to the coupling with the trans
ylidic P atom (4JP–H around 1–2 Hz). The 31P{1H}-
NMR spectrum of 17 shows two resonances in the
typical region of O-coordination (14.28 and 13.49 ppm)
‚
and the resonance attributed to the C P ring at 10.91
ppm (1JPt–P=4933.6 Hz). All these data are in keeping
with the structure depicted in Scheme 1.
1
In our experience, this behaviour does not have any
precedent. We have shown the ambidentate character
of the ylide Ph3PꢀCHCN in compound 7 allowing the
simultaneous coordination of two ylides in different
coordination modes. We have also shown that the
keto-stabilized ylides can also behave as ambidentates
(complexes 3–5 or 14, 15 and complexes 11, 12), but we
have not been successful in synthesizing a similar com-
plex to 7. In addition, all efforts to synthesize this kind
of product starting from 3–5 have led to the obtention
of the starting products or to decomposition. Complex
17 contains two ylides, but both are O-coordinated.
The question of why a simultaneous C- and O-coordi-
nation over the same metal is not possible still remains
unanswered, taking into account, in addition, that the
synthesis of 17 starting from 14 must occur with an
isomerization of one of the ylides, from C- to O-coordi-
nated. Further studies are in progress in order to shed
light on this maverick behaviour.
the H-NMR of the crystals).
Analysis: Calculated (C44H42ClNO5P2Pt.0.5CH2Cl2,
999.76 g mol−1): C, 53.46; H, 4.33; N, 1.40. Found: C,
53.79; H, 3.98; N, 1.28. IR (w, cm−1): 2326, 2291
(wNCMe), 1651 (wCO), 797, 586, 563, 476, 466 (w P).
‚
Mass spectrum (FAB+) [m/z, (%)]: 816 (85%) C[(M-
NCMe)+]. H-NMR (CD2Cl2, 188 K): l (ppm), 7.66–
1
6.74 (m, 27H, Ph+o-MeC6H4), 4.39 (d, 1H, CH ylide,
2JP–H=8.0 Hz), 3.26, 3.11 (AB spin system, 2H, CH2,
2JH–H=16.2 Hz), 2.66, 2.44, 2.39, 2.08 (4s, 12H, 2o-
MeC6H4+COMe+ NCMe). 31P{1H}-NMR (CD2Cl2,
188 K): l (ppm), 27.64 (d, C P, 1JPt–P=3391 Hz,
‚
3JP–P=8 Hz), 26.24 (d, -P+Ph3, JPt–P=78 Hz).
2
‚
3.3. Synthesis of [Pt(C P){C(H)(COPh)(PPh3)}-
(NCMe)]ClO4 4
Complex 4 was synthesized in the same way as 3:
[Pt(C P)(NCMe)2]ClO4 2 (0.200 g, 0.294 mmol) was
‚

S. Ferna´ndez et al. / Journal of Organometallic Chemistry 561 (1998) 67–76
73
reacted with Ph3PꢀC(H)COPh (0.112 g, 0.294 mmol) in
CH2Cl2 at r.t. to give 4 as a white solid. Obtained:
0.236 g (79% yield).
=3662 Hz, 3JP–P=11 Hz), 25.84 (d, −P+Ph3, 2JPt–P
92 Hz).
=
‚
Analysis: Calculated (C49H44ClNO5P2Pt, 1019.37 g
mol−1): C, 57.73; H, 4.35; N, 1.37. Found: C, 57.76; H,
4.00; N, 1.29. IR (w, cm−1): 2285, 2319 (wNCMe), 1629
3.6. Synthesis of [Pt(C P){C(H)(CN)(PPh3)}-
{NꢁC–C(H)ꢀPPh3}]ClO4 7
(wCO), 585, 563, 478, 466 (w P). Mass spectrum (FAB+)
Complex 7 was synthesized in the same way as 3:
‚
[m/z, (%)]: 879 (94%) C [(M-NCMe)+]. 1H-NMR
(CD2Cl2, 188 K): l (ppm), 8.15–6.55 (m, 32H, Ph+o-
MeC6H4), 5.47 (d, 1H, CH ylide, 2JP–H=11.5 Hz),
‚
[Pt(C P)(NCMe)2]ClO4 2 (0.117 g, 0.172 mmol) was
reacted with Ph3PꢀC(H)CN (0.103 g, 0.344 mmol) in
CH2Cl2 at r.t. to give 7 as a white solid. Obtained:
0.141 g (68% yield).
2
3.46, 3.15 (AB spin system, 2H, CH2, JH–H=16.7 Hz),
2.30 (s, 3H, o-MeC6H4), 1.97, 1.95 (2s, 6H, o-
MeC6H4+NCMe). 31P{1H}-NMR ((CD3)2CO, 188
K): l (ppm), 27.73 (d, −P+Ph3, 3JP–P=10.5 Hz),
Analysis: Calculated (C61H52ClN2O4P3Pt, 1200.55 g
mol−1): C, 61.02; H, 4.36; N, 2.33. Found: C, 60.15; H,
4.63; N, 2.19. IR (w, cm−1): 2175 (wCN-ylide), 530, 476
‚
1
(wCP ). Mass spectrum (FAB+) [m/z, (%)]: 1101 (31%)
‚
26.97 (d, C P, JPt–P=3471 Hz).
1
[M+]. H-NMR (CDCl3): l (ppm), 7.67–6.67 (m, 42H,
‚
2
3.4. Synthesis of [Pt(C P){C(H)(CO2Me)(PPh3)}-
Ph+o-MeC6H4), 3.13 (dd, 1H, CH C-ylide, JP–H
=
14.3 Hz, 3JP–H=8.6 Hz, 2JPt–H=83.3 Hz), 2.32 (m,
broad, 5H, CH2+o-MeC6H4), 1.99 (s, 3H, o-
(NCMe)]ClO4 5
Complex 5 was synthesized in the same way as 3:
2
MeC6H4), 1.27 (d, 1H, CH N-ylide, JP–H=4.8 Hz).
‚
[Pt(C P)(NCMe)2]ClO4 2 (0.200 g, 0.294 mmol) was
31P{1H}-NMR (CDCl3, 223 K): l (ppm), 26.67 (d,
reacted with Ph3PꢀC(H)CO2Me (0.098 g, 0.294 mmol)
in CH2Cl2 at r.t. to give 5 as a white solid. Obtained:
0.235 g (82% yield).
C P, 1JPt–P=3483 Hz, 3JP–P=10 Hz), 25.94 (d, −P+
‚
Ph3, C-ylide, 2JPt–P=99 Hz), 22.77 (s, CꢀPPh3, N-
ylide).
Analysis: Calculated (C44H42ClNO6P2Pt, 973.30 g
mol−1): C, 54.29; H, 4.35; N, 1.44. Found: C, 54.83; H,
4.53; N, 1.51. IR (w, cm−1): 2285, 2316 (wNCMe), 1686
(wCO), 752, 587, 563, 478, 466 (wC‚P). Mass spectrum
(FAB+) [m/z, (%)]: 832 (100%) [(M-NCMe)+]. 1H-
NMR (CDCl3, 223K): l (ppm), 7.74-7.16 (m, 27H,
Ph+o-MeC6H4), 3.82 (dd, 1H, CH ylide, 2JP–H=9
Hz, 3JP–H=4.1 Hz), 3.62 (s, 3H, CO2Me), 2.40 (s,
broad, 6H,o-MeC6H4), 2.44, 2.25 (AB spin system, 2H,
‚
3.7. Synthesis of trans-[Pt(C P)Cl(PPh3)] 8
‚
To a suspension of [Pt(C P)(v-Cl)]2 1 (1.000 g, 0.936
mmol) in CH2Cl2 (40 ml) PPh3 (0.491 g, 1.872 mmol)
was added and the resulting mixture was stirred at r.t..
The initial suspension gradually dissolved (ca. 30 min)
giving a colorless solution which was evaporated to
dryness. Treatment of the white residue with Et2O (30
ml) allows the isolation of a white solid, identified
spectroscopically as a mixture of the trans (8) and cis
(9) isomers (5:1 molar ratio). This solid was dissolved in
toluene and the resulting solution refluxed for 12 h,
then cooled and evaporated to dryness. Treatment of
the residue with Et2O (30 ml) allows the isolation of the
pure trans isomer 8. Obtained: 1.280 g (86% yield).
Complex 8 can also be obtained in a single step by
2
CH2, JH–H=9.1 Hz), 1.67 (s, 3H, NCMe). 31P{1H}-
‚
1
NMR (CDCl3, 223 K): l (ppm), 27.56 (d, C P, JPt–P
3
=3378 Hz, JP–P=9 Hz), 26.46 (d, −P+Ph3).
‚
3.5. Synthesis of [Pt(C P){C(H)(CN)(PPh3)}-
(NCMe)]ClO4 6
Complex 6 was synthesized in the same way as 3:
‚
[Pt(C P)(NCMe)2]ClO4 2 (0.200 g, 0.294 mmol) was
‚
reacting [Pt(C P)(v-Cl)]2 (0.500 g, 0.468 mmol) with
reacted with Ph3PꢀC(H)CN (0.088 g, 0.294 mmol) in
CH2Cl2 at r.t. to give 6 as a white solid. Obtained:
0.221 g (80% yield).
PPh3 (0.246 g, 0.936 mmol) in refluxing toluene (20 ml)
for 12 h. The resulting solution was evaporated to
dryness and the white residue treated with Et2O (25 ml),
giving pure 8 as a white solid. Obtained: 0.551 g (74%
yield).
Analysis: Calculated (C43H39ClN2O4P2Pt, 940.28 g
mol−1): C, 54.93; H, 4.18; N, 2.98. Found: C, 54.65; H,
4.00; N, 2.69. IR (w, cm−1): 2227 (broad, wNCMe+wNC-
ylide), 772, 590, 564, 512, 475, 464 (wC‚P). Mass spec-
trum (FAB+) [m/z, (%)]: 799 (100%) [(M-NCMe)+].
1H-NMR (CD2Cl2): l (ppm), 7.86–6.61 (m, 27H, Ph+
Analysis: Calculated (C39H35ClP2Pt, 796.194 g mol−
1): C, 58.83; H, 4.43. Found: C, 58.47; H, 3.93. IR (w,
cm−1): 1589, 1567, 806, 749, 584, 561, 534, 480, 469
1
2
(wC
), 279 (wPt–Cl). H-NMR (CDCl3, 223 K): l
(ppm), 7.66–6.78 (m, 27H, Ph+o-MeC6H4), 2.86 (s,
o-MeC6H4), 3.93 (dd, 1H, CH ylide, JP–H=13.8 Hz,
‚
P+PPh
3
2
3JP–H=8.7 Hz, JPt–H=93 Hz), 3.28, 1.79 (AX spin
2
2
5H, CH2+o-MeC6H4), 2.71 (s, 3H, o-MeC6H4).
system, 2H, CH2, JH–H=13.8 Hz, JPt–H=150 Hz),
2.39, 1.86 (2s, 6H,o-MeC6H4), 1.64 (s, 3H, NCMe).
31P{1H}-NMR (CD2Cl2): l (ppm), 35.87 (d, JPt–P
=
1
‚
2
1
31P{1H}-NMR (CD2Cl2): l (ppm), 27.35 (d, C P, 1JPt–P
3115 Hz, JP–P=446 Hz), 28.71 (d, JPt–P=3027 Hz).

74
S. Ferna´ndez et al. / Journal of Organometallic Chemistry 561 (1998) 67–76
‚
‚
2
3.8. Synthesis of trans-[Pt(C P)(PPh3)(NCMe)]ClO4 10
(C P+PPh3 11b, JP–P=382 Hz), 14.01 (s, CꢀPPh3
11b), 13.38 (s, CꢀPPh3 11a).
(a) To a solution of 8 (0.200 g, 0.251 mmol) in 25 ml
of NCMe (25 ml) TlClO4 (0.076 g, 0.251 mmol) was
added and the resulting suspension was refluxed for 1 h.
After cooling, the suspension was filtered and the re-
sulting solution evaporated to dryness, giving an oily
residue which was triturated with Et2O (25 ml). The
resulting white solid (10) was filtered and air dried.
Obtained: 0.192 g (85% yield). (b) To a solution of
‚
3.10. Synthesis of [Pt(C P){OC(OMe)ꢀC(H)(PPh3)}
(PPh3)]ClO4 12
Complex 12 was synthesized in the same way as 11:
[Pt(C P)(PPh3)(NCMe)]ClO4 10 (0.138 g, 0.153 mmol)
‚
was reacted with Ph3PꢀC(H)CO2Me (0.051 g, 0.153
mmol) in CH2Cl2 at r.t. to give 12 as a mixture of the
transoid 12a and cisoid 12b isomers in molar ratio of
12a:12b=3:1 Obtained: 0.125 g (66% yield). Complex
12 was recrystallized from CH2Cl2/n-hexane, giving col-
orless crystals of 12.0.5CH2Cl2, which were used for
analytical and NMR measurements (the amount of
‚
[Pt(C P)(NCMe)2]ClO4 2 (0.360 g, 0.529 mmol) in 40
ml of CH2Cl2 PPh3 (0.138 g, 0.529 mmol) was added
and the resulting solution was stirred for 30 min at r.t..
The solvent was then evaporated to dryness and the
residue treated with Et2O (35 ml) giving a white solid
(10), which was collected and air dried. Obtained: 0.432
g (90% yield).
1
CH2Cl2 was quoted from the H-NMR of the crystals).
Analysis: Calculated (C60H54ClO6P3Pt.0.5CH2Cl2,
1237.0 g mol−1): C, 58.74; H, 4.48. Found: C, 58.75; H,
Analysis: Calculated (C41H38ClNO4P2Pt, 901.24 g
mol−1): C, 54.64; H, 4.25; N, 1.55. Found: C, 54.41;
H, 4.10; N, 1.42. IR (w, cm−1): 2317, 2287 (wNCMe),
1591, 776, 766, 755, 588, 562, 536, 518, 493, 473, 464
4.84. IR (w, cm−1): 1542 (wCO), 586, 471 (wCP ). Mass
‚
spectrum (FAB+) [m/z, (%)]: 1094 (6%) [M+], 832
(3%) [(M-PPh3)+], 760 (100%) [(M-ylide)+]. H-NMR
1
(wC P+PPh ). Mass spectrum (FAB+) [m/z, (%)]: 801
(CDCl3): l (ppm), 7.75–6.82 (m, Ph+o-MeC6H4), 3.12
(d, CH ylide 12a, 2JP–H=18.4 Hz), 2.75 (s, CO2Me
12a), 2.61 (s, CO2Me 12b), 2.42 (s, o-MeC6H4 12a),
2.39 (s, o-MeC6H4 12b), 1.82 (s, o-MeC6H4 12b), 1.61
(s, o-MeC6H4 12a). 31P{1H}-NMR (CDCl3): l (ppm),
‚
(5%) [M+], 760 (100%) [(M-NCMe)+]. 1H-NMR
3
(CD2Cl2):
l (ppm), 7.62–7.12 (m, 27H, Ph+o-
MeC6H4), 2.64 (s, broad, 8H, CH2 +o-MeC6H4), 1.57
(s, 3H, NCMe). 31P{1H}-NMR (CD2Cl2): l (ppm),
2
1
1
1
33.19 (d, JP–P=384 Hz, JPt–P=2966 Hz), 27.81 (d,
1JPt–P=2934 Hz).
36.41 (d, JPt–P=3173 Hz), 29.88 (d, JPt–P=3293 Hz)
‚
2
1
(C P+PPh3, 12a, JP–P=411 Hz), 32.96 (d, JPt–P
=
2964 Hz), 27.71 (d, 1JPt–P=2931 Hz) (C P+PPh3,
‚
2
‚
12b, JP–P=386 Hz), 15.76 (s, broad, C=PPh3 12a+
3.9. Synthesis of [Pt(C P){OC(Me)ꢀC(H)(PPh3)}
12b).
(PPh3)]ClO4 11
‚
‚
3.11. Synthesis of [Pt(C P){NꢁC–C(H)ꢀPPh3}
To a solution of [Pt(C P)(PPh3)(NCMe)]ClO4 10
(PPh3)]ClO4 13
(0.200 g, 0.222 mmol) in 30 ml of CH2Cl2
Ph3PꢀC(H)COMe (0.070 g, 0.222 mmol) was added and
the resulting solution was stirred for 30 min at r.t. and
then evaporated to dryness. The white residue was
treated with Et2O (25 ml), giving a white solid which
was filtered, washed with additional Et2O (25 ml) and
air dried. This solid was identified spectroscopically as a
mixture of the transoid 11a and cisoid 11b isomers in
molar ratio 11a:11b=1.44:1. Obtained: 0.166 g (64%
yield).
Complex 13 was synthesized in the same way as 11:
[Pt(C P)(PPh3)(NCMe)]ClO4 10 (0.146 g, 0.162 mmol)
was reacted with Ph3PꢀC(H)CN (0.049 g, 0.162 mmol)
in CH2Cl2 at r.t. to give 13 as a white solid. Obtained:
0.083 g (44% yield).
‚
Analysis: Calculated (C59H51ClNO4P3Pt, 1161.52 g
mol−1): C, 61.10; H, 4.42; N, 1.20. Found: C, 61.10; H,
4.01; N, 1.03. IR (w, cm−1): 2176 (wCN), 560, 536, 472
(wC P). Mass spectrum (FAB+) [m/z, (%)]: 1061 (57%)
Analysis: Calculated (C60H54ClO5P3Pt, 1178.5
g
‚
[M+], 799 (12%) [(M-PPh3)+], 760 (100%) [(M-ylide)+].
1H-NMR (CDCl3): l (ppm), 7.46–6.86 (m, 42H, Ph+
o-MeC6H4), 3.07 (s, broad, 2H, CH2), 2.42 (s, 6H,
o-MeC6H4), 1.06 (dt, 1H, CH ylide, 2JP–H=5.2 Hz,
5JP–H=0.9 Hz). 31P{1H}–NMR (CDCl3): l (ppm),
mol−1): C, 61.15; H, 4.62. Found C, 60.80; H, 4.72. IR
‚
(w, cm−1): 1504 (wCO), 780, 587, 536, 471 (w P). Mass
C
spectrum (FAB+) [m/z, (%)]: 1078 (10%) [M+], 816
(6%) [(M-PPh3)+], 760 (100%) [(M-ylide)+]. H-NMR
1
(CDCl3): l (ppm), 7.53–6.94 (m, Ph+o-MeC6H4), 4.41
(d, CH ylide 11a, JP–H=18.4 Hz), 3.59 (d, CH ylide
11b, JP–H=21.2 Hz), 2.91, 2.07 (2 broad s, CH2 11a),
1
1
2
32.38 (d, JPt–P=3022 Hz), 26.98 (d, JPt–P=2964 Hz)
(C P+PPh3, JP–P=406 Hz), 21.95 (s, C=PPh3).
‚
2
2
2.72 (s, o-MeC6H4 11b), 2.61 (s, o-MeC6H4 11a), 2.38
(s, o-MeC6H4 11a), 2.16 (s, o-MeC6H4 11b), 1.83 (s,
COMe 11b), 1.67 (s, COMe 11a). 31P{1H}-NMR
‚
3.12. Synthesis of [Pt(C P)Cl{C(H)(COMe)(PPh3)}]
14
1
(CDCl3): l (ppm), 36.25 (d, JPt–P=3198 Hz), 28.25 (d,
‚
2
‚
1JPt–P=3098 Hz) (C P+PPh3 11a, JP–P=414 Hz),
To a suspension of [Pt(C P)(v-Cl)]2 1 (0.100 g, 0.093
mmol) in CH2Cl2 (20 ml) Ph3PꢀC(H)COMe (0.059 g,
1
1
32.97 (d, JPt–P=2964 Hz), 27.71 (d, JPt–P=2932 Hz)

S. Ferna´ndez et al. / Journal of Organometallic Chemistry 561 (1998) 67–76
75
0.187 mmol) was added and the resulting mixture was
refluxed for 4 h, resulting in the gradual dissolution of
the suspension. After the reaction time, the resulting
solution was evaporated to dryness and the residue
treated with n-hexane (25 ml), giving a white solid
which was collected, washed with additional n-hexane
(20 ml), air dried and identified as 14. Obtained: 0.126
g (79% yield). This complex was recrystallized from
Analysis: Calculated (C41H36ClNP2Pt.0.5CH2Cl2,
877.69 g mol−1): C, 56.79; H, 4.25; N, 1.59. Found: C,
56.59; H, 4.03; N, 1.56. IR (w, cm−1): 2187 (wCN), 747,
588, 560, 529, 476 (wC ), 266 (wPt–Cl). Mass spectrum
‚
P
1
(FAB+) [m/z, (%)]: 799 (100%) [(M-Cl)+]. H-NMR
(CD2Cl2):
l (ppm), 7.90–6.78 (m, 27H, Ph+o-
2
3
MeC6H4), 4.22 (dd, 1H, CH ylide, JP–H=15 Hz, JP–
H=8.4 Hz, 2JPt–H=79 Hz), 2.80, 2.19 (AB spin
2
CH2Cl2/n-hexane
giving
colorless
crystals
of
system, 2H, CH2, JH–H=16 Hz), 2.70, 2.58 (2s, 6H,
14.0.5CH2Cl2 which were used for analytical and NMR
o-MeC6H4). 31P{1H}-NMR (CD2Cl2): l (ppm), 28.59
(s, broad, C P, JPt–P=3666 Hz), 26.08 (d, −P+Ph3,
‚
1
measurements (the amount of CH2Cl2 was quoted from
1
2JPt–P=73 Hz, JP–P=10 Hz).
3
the H-NMR of the crystals).
Analysis: Calculated (C42H39ClOP2Pt.0.5CH2Cl2,
894.72 g mol−1): C, 57.05; H, 4.50. Found: C, 57.36; H,
4.41. IR (w, cm−1): 1648 (wCO), 752, 589, 564, 484, 476,
‚
3.15. Synthesis of [Pt(C P){OC(Me)ꢀC(H)(PPh3)}2]
ClO4 17
464 (wC ), 266 (wPt–Cl). Mass spectrum (FAB+) [m/z,
‚
P
1
(%)]: 851 (7%) [M+], 816 (100%) [(M-Cl)+]. H-NMR
To
a
THF solution (20 ml) of complex
‚
(CDCl3):
l (ppm), 7.87–6.70 (m, 27H, Ph+o-
[Pt(C P)Cl{C(H)(COMe)(PPh3)}] 14 (0.142 g, 0.166
mmol) TlClO4 (0.050 g, 0.166 mmol) was added and the
resulting suspension was stirred at r.t. for 1 h, then
filtered. To the freshly prepared solution of
MeC6H4), 5.53 (dd, 1H, CH ylide, 2JP–H=8.5 Hz,
3JP–H=3.2 Hz, 2JPt–H=60 Hz), 2.68 (s, broad, 8H,
o-MeC6H4+CH2), 2.46 (d, 3H, COMe, 4JP–H=2.3
Hz). 31P{1H}-NMR (CDCl3): l (ppm), 27.32 (s, broad,
‚
[Pt(C P)(THF){C(H)(COMe)(PPh3)}]ClO4,
‚
1
3
C P, JPt–P=3790 Hz), 24.90 (d, −P+Ph3, JP–P=10
Ph3PꢀC(H)COMe (0.053 g, 0.166 mmol) was added and
stirring was continued for 30 min. Subsequent evapora-
tion of the resulting solution and treatment of the white
residue with n-hexane permitted the isolation of a white
solid which was identified as 17. Obtained: 0.184 g (90%
yield).
2
Hz, JPt–P=53 Hz).
‚
3.13. Synthesis of [Pt(C P)Cl{C(H)(COOMe)(PPh3)}]
15
Complex 15 was synthesized in the same way as 14:
Analysis: Calculated (C63H58ClO6P3Pt, 1234.61 g
‚
mol−1) C, 61.29; H, 4.73. Found: C, 60.74; H, 4.69. IR
[Pt(C P)(v-Cl)]2 1 (0.150 g, 0.140 mmol) was reacted
(w, cm−1): 1505 (wCO), 750, 593 (wCP ). Mass spectrum
‚
with the ylide Ph3PꢀC(H)CO2Me (0.094 g, 0.281 mmol)
in refluxing CH2Cl2 to give 15 as a white solid. Ob-
tained: 0.209 g (86% yield).
1
(FAB+) [m/z, (%)]: 816 (48%) [(M-ylide)+]. H-NMR
(CD2Cl2):
l (ppm), 7.68–6.84 (m, 42H, Ph+o-
MeC6H4), 4.33 (dd, 1H, CH ylide trans to P, 2JP–H=24
Analysis: Calculated (C42H39ClO2P2Pt, 868.26
g
mol−1): C, 58.10; H, 4.52. Found C, 58.26; H, 4.70. IR
‚
5
Hz, JP–H=2.3 Hz), 3.87 (d, 1H, CH ylide trans to C,
(w, cm−1): 1688 (wCO), 586, 565, 521, 474, 466 (w P),
2JP–H=23 Hz), 3.05, 2.95 (AB spin system, 2H, CH2,
2JH–H=15 Hz), 2.18 (d, 3H, COMe ylide trans to P,
4JP–H=2 Hz), 2.01 (d, 3H, COMe ylide trans to C,
4JP–H=1.3 Hz), 1.99, 1.81 (2s, 6H, o-MeC6H4).
31P{1H}-NMR (CD2Cl2): l (ppm), 14.28 (s, C=PPh3
ylide trans to P), 13.49 (s, C=PPh3 ylide trans to C),
C
266 (wPt–Cl). Mass spectrum (FAB+) [m/z, (%)]: 832
1
(8%) [(M-Cl)+]. H-NMR (CDCl3): l (ppm), 7.88–6.72
(m, 27H, Ph+o-MeC6H4), 4.96 (d, 1H, CH ylide,
2
2JP–H=9 Hz, JPt–H=62 Hz), 3.57 (s, 3H, CO2Me),
2
3.42, 2.42 (AB spin system, 2H, CH2, JH–H=15 Hz),
2.68, 2.64 (2s, 6H, o–MeC6H4). 31P{1H}NMR (CDCl3):
‚
1
10.91 (s, C P, JPt–P=4934 Hz).
‚
1
l (ppm), 27.60 (s, broad, C P, JPt–P=3726 Hz), 25.2
2
3
(d, −P+Ph3, JPt–P=67 Hz, JP–P=11 Hz).
Acknowledgements
‚
3.14. Synthesis of [Pt(C P)Cl{C(H)(CN)(PPh3)}] 16
We would like to thank the Direccio´n General de
Ensen˜anza Superior (Spain) for its financial support
(Project PB95-0003-C02-01) and Professor J. Fornie´s
for his invaluable logistical support.
Complex 16 was synthesized in the same way as 14,
except that the reaction was performed at r.t.:
‚
[Pt(C P)(v-Cl)]2 1 (0.100 g, 0.093 mmol) was reacted
with Ph3PꢀC(H)CN (0.056 g, 0.187 mmol) in CH2Cl2 at
r.t. to give 16 as a white solid. Obtained: 0.129 g (82%
yield). Recrystallization of 16 in CH2Cl2/n-hexane gave
crystals of 16.0.5CH2Cl2, which were used for analytical
and NMR purposes (the amount of CH2Cl2 was quoted
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