Unusual formation and reactivity of a diplatinum μ-phenylethenylidene complex: Synthesis and structures of cis,cis-[(PPh3)(C6F5) 2Pt(μ-η1:η3-CHPhCCO)Pt(PPh 3)2] and cis,cis-[(PPh3)2Pt{μ-η2(C,S):η

Article abstract of DOI:10.1021/om950891x

The μ-phenylethenylidene-bridged diplatinum complex [(OC)(C₆F₅)₂Pt(μ-C=CHPh)Pt-(PPh ₃)₂], 1, synthesized from the reaction between the mononuclear alkynyl-hydride trans-[Pt(C≡CPh)H(PPh₃)₂] and cis-[Pt(C₆F₅)₂(CO)(THF)] (THF = tetrahydrofuran), displays a remarkable reactivity associated with the μ-vinylidene ligand under mild conditions. The reaction of 1 with PPh₃ (molar ratio 1:1) produces an unprecedented reductive coupling of the CO ligand and the vinylidene bridging group to give the compound cis,cis-[(PPh₃)(C₆F₅) ₂-Pt(μ-η¹:η³-CHPhCCO)Pt(PPh ₃)₂], 2, which contains an expanded, unsaturated benzylideneketene bridging ligand. On the other hand, treatment of 1 with PhSH generates the new diplatinum compound cis,cis-[(PPh₃)₂Pt{μ-η²(C,S):η ¹(C)-C(SPh)(CH₂Ph)}Pt(C₆F₅) ₂(CO)], 3, formed by a formal addition of the PhSH to the carbon-carbon double bond of the vinylidene group in 1. The structures of 2 and 3 have been fully elucidated by X-ray diffraction studies.

Full text of DOI:10.1021/om950891x

1014
Organometallics 1996, 15, 1014-1022
Un u su a l F or m a tion a n d Rea ctivity of a Dip la tin u m
µ-P h en yleth en ylid en e Com p lex: Syn th esis a n d
Str u ctu r es of
cis,cis-[(P P h 3)(C6F 5)2P t(µ-η1:η3-CHP h CCO)P t(P P h 3)2] a n d
cis,cis-[(P P h 3)2P t{µ-η2(C,S):η1(C)-C(SP h )(CH2P h )}P t(C6F 5)2(CO)]
Din u clea r Com p ou n d s
Irene Ara,† J esu´s R. Berenguer,‡ J uan Fornie´s,*,† Elena Lalinde,*,‡ and
Milagros Toma´s†
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza-CSIC, E-50009 Zaragoza, Spain, and Departamento de Qu´ımica,
Universidad de La Rioja, 26001 Logron˜o, Spain
Received November 17, 1995X
The µ-phenylethenylidene-bridged diplatinum complex [(OC)(C6F5)2Pt(µ-CdCHPh)Pt-
(PPh3)2], 1, synthesized from the reaction between the mononuclear alkynyl-hydride trans-
[Pt(CtCPh)H(PPh3)2] and cis-[Pt(C6F5)2(CO)(THF)] (THF ) tetrahydrofuran), displays a
remarkable reactivity associated with the µ-vinylidene ligand under mild conditions. The
reaction of 1 with PPh3 (molar ratio 1:1) produces an unprecedented reductive coupling of
the CO ligand and the vinylidene bridging group to give the compound cis,cis-[(PPh3)(C6F5)2-
Pt(µ-η1:η3-CHPhCCO)Pt(PPh3)2], 2, which contains an expanded, unsaturated benzylideneketene
bridging ligand. On the other hand, treatment of 1 with PhSH generates the new diplatinum
compound cis,cis-[(PPh3)2Pt{µ-η2(C,S):η1(C)-C(SPh)(CH2Ph)}Pt(C6F5)2(CO)], 3, formed by a
formal addition of the PhSH to the carbon-carbon double bond of the vinylidene group in
1. The structures of 2 and 3 have been fully elucidated by X-ray diffraction studies.
In tr od u ction
Methods for preparing this type of compound are
generally based on (a) addition of an electrophile to a
bridging acetylide,2de,5 (b) metal coordination of ad-
equate metal-ligand fragments to a terminal vinylidene
ligand,6 or (c) generation of a vinylidene fragment from
gem-dihalo olefins in the presence of a potential or
actual binuclear system.3bc,7 Another route to such
species involves the isomerization of terminal alkynes.2c,8
This last process (acetylene to vinylidene tautomerism),
thoroughly investigated on mononuclear metal
systems,2ab,9 has been much less studied on binuclear
species and is not well understood. Theoretical calcula-
Organometallic complexes in which two or more
metals are linked by a hydrocarbon bridge have been
extensively studied as models for species postulated to
be present in several important metal-catalyzed reac-
tions.1 Investigation on the ways in which metal-
carbon and carbon-carbon bonds are made and broken
in these soluble complexes can provide useful informa-
tion about similar processes that occur in homogeneous
catalytic reactions and on metal surfaces. Vinylidene-
bridged complexes are a type of C2-bridged compounds
which are attracting considerable interest.2 Recent
reports demonstrate interesting chemistry at µ-alk-
enylidene ligands,2bc,3 and furthermore, surface-bound
vinylidene ligands have been proposed to play a key role
in hydrocarbon chain growth in the heterogeneously
catalyzed Fischer-Tropsch process (“McCandlish
mechanism”).3f-h,4
(3) (a) Conole, G. C.; Froom, S. F. T.; Green, M.; McPartlin, M. J .
Chem. Soc., Chem. Commun. 1989, 92. (b) J acobsen, E. N.; Bergman,
R. G. Organometallics 1984, 3, 329. (c) J acobsen, E. N.; Bergman, R.
G. J . Am. Chem. Soc. 1985, 107, 2023. (d) Yamazaki, H.; Wakatsuki,
Y. J . Organomet. Chem. 1984, 272, 251. (e) Casey, C. P.; Marder, S.
R. Organometallics 1985, 4, 411. (f) Hoel, E. L.; Ansell, G. B.; Leta, S.
Organometallics 1984, 3, 1633. (g) Hoel, E. L.; Ansell, G. B.; Leta, S.
Organometallics 1986, 5, 585. (h) Hoel, E. L. Organometallics 1986,
5, 587. (i) Casey, C. P.; Austin, E. A. Organometallics 1986, 5, 584. (j)
Casey, C. P.; Austin, E. A. J . Am. Chem. Soc. 1988, 110, 7106. (k)
Lewandos, G. S.; Doherty, N. M.; Knox, S. A. R.; MacPherson, K. A.;
Orpen, A. G. Polyhedron 1988, 7, 83. (l) Casey, C. P.; Miles, W. H.;
Fagan, P. J .; Haller, K. J . Organometallics 1985, 4, 559. (m) Baralt,
E.; Lukehart, C. M.; McPhail, A. T.; McPhail, D. R. Organometallics
1991, 10, 516. (n) Etienne, M.; Guerchais, J . E. J . Chem. Soc., Dalton
Trans 1989, 2187. (o) Etienne, M.; Talarmin, J .; Toupet, L. Organo-
metallics 1992, 11, 2058.
† Universidad de Zaragoza.
‡ Universidad de La Rioja.
X Abstract published in Advance ACS Abstracts, J anuary 1, 1996.
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0276-7333/96/2315-1014$12.00/0 © 1996 American Chemical Society

Diplatinum µ-Phenylethenylidene Complexes
Organometallics, Vol. 15, No. 3, 1996 1015
tions by Silvestre and Hoffman10 showed that a con-
certed 1,2-hydrogen shift, accepted in related reactions
mediated by a single metal center, was energetically
unlikely on a binuclear system, although this transfor-
mation via an acetylide-hydride intermediate appeared
to be plausible. Although strong support for such a
mechanism comes from Lukehart’s systematic synthesis
of bridging vinylidene complexes by the addition of a
Pt-H bond across the carbon-carbon triple bond of
several metal alkynyl compounds,11 experimental evi-
dence for such acetylide-hydride intermediates has
been sparse.8h
Sch em e 1
In this paper, we report the synthesis and character-
ization of a new vinylidene-bridged dinuclear platinum
complex [(OC)(C6F5)2Pt(µ-CdCHPh)Pt(PPh3)2], 1, which
has been obtained by direct reaction between the
alkynyl-hydride mononuclear complex trans-[Pt-
(CtCPh)H(PPh3)2] and cis-[Pt(C6F5)2(CO)(THF)] (THF
) tetrahydrofuran). Furthermore, some aspects of its
remarkable reactivity are also included. Particularly
interesting are the reactions of 1 with PPh3 and
thiophenol under mild conditions. The Lewis base
triphenylphosphine induces an unprecedented reductive
coupling of the CO ligand and the vinylidene bridging
group yielding the first µ-η1:η3 benzylideneketene di-
nuclear platinum complex [(PPh3)(C6F5)2Pt(µ-CHPhC-
CO)Pt(PPh3)2], 2. By contrast, PhSH adds to the
carbon-carbon double bond of the :CdCHPh group of
Resu lts a n d Discu ssion
In previous studies12 involving the monocarbonyl
complex cis-[Pt(C6F5)2(CO)(THF)] (THF ) tetrahydro-
furan), we have discovered its unusual reactivity toward
terminal alkynyl compounds LnMCtCR, which results
in the formation of mono µ-η2-acetylide-bridged di-
nuclear zwitterionic derivatives of the type [(CO)(C6F5)2-
Pt-(µ-η2-CtCR)M+Ln]12 through an unexpected alkyn-
ylation of the monocarbonyl fragment “cis-Pt(C6F5)2-
(CO)”, probably brought about by the enhanced acidity
of the platinum center, due to the electron-withdrawing
nature of the C6F5 groups and the good π-acceptor
properties of the CO ligand. As an extension on the
study of the reactivity of this monocarbonyl complex cis-
[Pt(C6F5)2(CO)(THF)], we have carried out its reaction
with trans-[PtH(CtCPh)(PPh3)2], which does not pro-
duce the expected µ-η2-acetylide hydride zwitterionic
complex (A, Scheme 1) but the phenylethenylidene-
bridged dinuclear [(OC)(C6F5)2Pt(µ-CdCHPh)Pt(PPh3)2],
1.
1
to give the dinuclear platinum complex
[(PPh3)2Pt(PhSCCH2Ph)Pt(C6F5)2(CO)], 3, which con-
tains a µ-η2(C,S):η1(C) (benzylthiophenoxy)methylene
bridging ligand. These reactions add to a growing body
of evidence suggesting that µ-alkenylidenes in dinuclear
and polynuclear complexes are versatile reactive ligands
for which a rich chemistry can be anticipated.2b
Thus, when the phenylacetylide-hydride complex,
trans-[Pt(CtCPh)H(PPh3)2], is treated with 1 equiv of
cis-[Pt(C6F5)2(CO)(THF)] in CH2Cl2, at room tempera-
ture for 15 h, the diplatinum complex [(OC)(C6F5)2Pt-
(µ-CdCHPh)Pt(PPh3)2], 1, is isolated in 55% yield as an
air-stable microcrystalline orange product. Analytical
and mass spectral data are in accord with this formula-
tion. Spectroscopic data (NMR and IR) are consistent
with a “T-frame” structure (C1 symmetry, shown in
Scheme 1), similar to those reported by Lukehart et al.
for several neutral and cationic diplatinum complexes
containing analogous phenylethenylidene bridging
ligands,11,13 with the main coordination planes of the
two platinum atoms having an orthogonal relative
orientation. The IR spectrum shows the ν(CO) band at
2083 cm-1, thus confirming the presence of a terminal
carbonyl ligand. Moreover, the presence of two absorp-
tions at 807 and 795 cm-1, due to the IR-active vibra-
tions of the X-sensitive mode of the C6F5 groups,12,14 and
the presence of four absorptions at 542, 522, 513, and
508 cm-1, due to the PPh3 ligands,15 suggests a mutually
(6) (a) Werner, H.; Wolf, J .; Mu¨ller, G.; Kru¨ger, C. Angew. Chem.,
Int. Ed. Engl. 1984, 23, 431. (b) Werner, H.; Wolf, J .; Mu¨ller, G.;
Kru¨ger, C. J . Organomet. Chem. 1988, 342, 381. (c) Kolobova, N. E.;
Ivanov, L. L.; Zhvanko, O. S.; Batsanov, A. S.; Struchkov, Yu. T. J .
Organomet. Chem. 1985, 279, 419. (d) Antonova, A. B.; Kovalenko, S.
V.; Korniyets, E. D.; Petrovsky, P. V.; Gulbis, G. R.; J ohansson, A. A.
Inorg. Chim. Acta 1985, 96, 1. (e) Werner, H.; Garc´ıa Alonso, F. J .;
Otto, H.; Peters, K.; von Schenering, H. G. J . Organomet. Chem. 1985,
289, C5. (f) Werner, H.; Garc´ıa Alonso, F. J .; Otto, H.; Peters, K.; von
Schenering, H. G. Chem. Ber. 1988, 121, 1565. (g) Weinand, R.; Werner,
H. J . Chem. Soc., Chem. Commun. 1985, 1145. (h) Schneider, D.;
Werner, H. Organometallics 1993, 12, 4420.
(7) (a) Fontaine, X. L. R.; Higgins, S. J .; Shaw, B. L.; Thornton-
Pett, M.; Yichang, W. J . Chem. Soc., Dalton Trans. 1987, 1501. (b)
Higgins, S. J .; Shaw, B. L. J . Chem. Soc., Chem. Commun. 1986, 1629.
(c) Fontaine, X. L. R.; Higgins, S. J .; Shaw, B. L. J . Chem. Soc., Dalton
Trans. 1988, 1179. (d) Davies, J . A.; Pinkerton, A. A.; Syed, R.; Wilmer,
M. J . Chem. Soc., Chem. Commun. 1988, 47.
(8) (a) Garc´ıa Alonso, F. J .; Garc´ıa Sanz, M.; Riera, V.; Ruiz, M. A.;
Tiripicchio, A.; Tiripicchio-Camellini, M. Angew. Chem., Int. Ed. Engl.
1988, 27, 116. (b) Antonova, A. B.; Kolobova, N. E.; Petrovsky, P. V.;
Lokshin, B. V.; Obezyuk, N. S. J . Organomet. Chem. 1977, 137, 55. (c)
Alt, A. G.; Engelhardt, H. E.; Steinlein, E.; Rogers, R. D. J . Organomet.
Chem. 1988, 344, 321. (d) Berry, D. H.; Eisenberg, R. J . Am. Chem.
Soc. 1985, 107, 7181. (e) Berry, D. H.; Eisenberg, R. Organometallics
1987, 6, 1796. (f) Dickson, R. S.; Fallon, G. D.; McClure, F. I.; Nesbit,
R. J . Organometallics 1987, 6, 215. (g) Doherty, N. M.; Elschenbroich,
C.; Kneuper, H. J .; Knox, S. A. R. J . Chem. Soc., Chem. Commun. 1985,
170. (h) Xiao, J .; Cowie, M. Organometallics 1994, 12, 463.
(9) (a) Bianchini, C.; Peruzzini, M.; Vacca, A.; Zanobini, F. Orga-
nometallics 1991, 10, 3697 and references therein. (b) Bly, R. S.; Zhong,
Z.; Kane, C.; Bly, R. K. Organometallics 1994, 13, 899 and references
therein.
(12) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.; Mart´ınez, F.; Urrio-
labeitia, E.; Welch, A. J . J . Chem. Soc., Dalton Trans. 1994, 1291.
(13) Baralf, E.; Boudreaux, E. A.; Demas, J . N.; Lenhert, P. G.;
Lukehart, C. M.; McPhail, A. T.; McPhail, D. R.; Myers, J . B., J r.;
Sacksteder, L.; True, W. R. Organometallics 1989, 8, 2417.
(14) (a) Maslowsky, E., J r. Vibrational Spectra of Organometallic
Compounds; Wiley: New York, 1977; p 437. (b) Uso´n, R.; Fornie´s, J .;
Espinet, P.; Fortun˜o, C.; Toma´s, M.; Welch, A. J . J . Chem. Soc., Dalton
Trans. 1988, 3005.
(10) Silvestre, J .; Hoffmann, R. Helv. Chim. Acta 1985, 68, 1461.
(11) (a) Afzal, D.; Lenhert, P. G.; Lukehart, C. M. J . Am. Chem. Soc.
1984, 106, 305. (b) Afzal, D.; Lukehart, C. M. Organometallics 1987,
6, 546.

1016 Organometallics, Vol. 15, No. 3, 1996
Ara et al.
F igu r e 1. 19F NMR spectra of complex [(OC)(C6F5)2Pt(µ-CdCHPh)Pt(PPh3)2], 1, in CDCl3 at different temperatures: (a)
-50 °C; (b) 20 °C; (c) 50 °C.
1
cis disposition for these ligands. The H and 31P NMR
spectra of complex 1 can be readily interpreted on the
basis of previous analysis of the NMR spectra for the
analogous cationic [Pt2(µ-CdCHPh)(CtCPh)(PEt3)4]-
[BF4] and neutral [Pt2(µ-CdCHPh)(CtCPh)(PEt3)3X]
and [Pt2(µ-CdCHPh)(PEt3)3X2] diplatinum complexes
reported by Lukehart.11,13,16 For complex 1, the alk-
enylidene proton resonance appears as a doublet of
doublets centered at 5.75 ppm due to 4J (P-H) coupling
to the two PPh3 ligands coordinated to Pt(2) (see Scheme
1). On the basis of previous observations, the value of
The 19F NMR spectral data are also informative. For
the proposed structure, the two C6F5 groups are in-
equivalent and, in addition, the low symmetry makes
the o-fluorine atoms (and the m-fluorine atoms as well),
within each C6F5 ligand, inequivalent. Thus, for a static
structure, the 19F NMR spectrum should show a com-
plex pattern with four o-, two p-, and four m-fluorine
resonances, i.e. five different signals for each C6F5 group.
The 19F NMR spectra registered in CDCl3 at different
temperatures (-50, 20, and 50 °C) are shown in Figure
1. As can be observed, the inequivalence of the two C6F5
ligands can be easily inferred from the presence of two
different triplets due to p-fluorine resonances. At low
temperature (-50 °C) the spectrum shows the expected
two o- and two m-fluorine signals for a rigid conforma-
tion of one of the two C6F5 groups. The only two (one
o-F and one m-F) sharp resonances observed for the
other C6F5 ligand clearly suggest the existence of a
dynamic process. When the temperature is increased,
the four resonances (two o-F and two m-F) of the former
C6F5 group broaden and, finally, collapse (the o-signals
practically disappear into the baseline) to only two at
50 °C. The observed spectrum at 50 °C can tentatively
be explained by assuming the rotation of C6F5 rings
around the Pt-Cipso(C6F5) bonds. Moreover, the differ-
ent aspects of the signals for each one of the C6F5 rings
(sharp and broad) in the o-F and m-F regions suggest
that the energy barrier for this process is different in
each ring. As a consequence, at low temperature (-50
°C) this process seems to be stopped for only one of the
C6F5 rings. A similar behavior has been previously
found in other complexes containing the “cis-Pt(C6F5)2-
(CO)” fragment.12a Unfortunately, the 13C NMR spec-
trum is not informative since only a complex pattern of
carbon resonances in the aromatic region is observed.
4
the two J (P-H) coupling constants (26.3 and 8.3 Hz,
respectively) suggest11b,13 that complex 1 is isolated as
the isomer shown in Scheme 1. The 31P NMR spectrum
shows two doublets with a 2J (PA-PX) of 14 Hz, which
is consistent with the presence of two inequivalent PPh3
ligands. The resonance at 31.17 ppm with a normal17
1J (Pt(2)-PX) of 2593 Hz (2J (Pt(1)-PX) not resolved) is
assigned to the PPh3 ligand in a nearly cis disposition
to Pt(1). The signal at 35.95 ppm, assigned to the PPh3
ligand nearly trans to Pt(1), shows two well-resolved Pt
satellites: 1J (Pt(2)-PA) ) 5534 Hz and J (Pt(1)-PA) )
2
344 Hz, respectively. These unusually large coupling
constants compare well with those reported for the
neutral [Pt2(µ-CdCHPh)(CtCPh)(PEt3)3X], [Pt2(µ-
CdCHPh)(PEt3)3X2],13,16 and [X(PPh3)Pt(µ-CO)Pt-
(PPh3)2X] (X ) Cl,18a Br18b) diplatinum complexes, all
of which have been described as containing a platinum-
platinum bond with some degree of mixed-valence
character. A Pt(1)fPt(2) formal Lewis acid-base in-
teraction has also been proposed to rationalize the
presence of a Pt-Pt bond in these types of com-
pounds.11,13,16 In addition, simulation of the 31P NMR
experimental spectrum using these assignements gives
good agreement with the experimental spectrum.
The formation of 1 from cis-[Pt(C6F5)2(CO)(THF)] and
trans-[Pt(CtCPh)H(PPh3)2] could involve an initial
alkynylation of the “cis-Pt(C6F5)2(CO)” fragment and
simultaneous stabilization of the resulting unit by
formation of a µ-acetylide hydride intermediate species
of the type cis,trans-[(OC)(C6F5)2Pt(µ-η1:η2-CtCPh)PtH-
(PPh3)2] (A, Scheme 1) (as observed in the reaction
(15) Mastin, S. H. Inorg. Chem. 1974, 13, 1003.
(16) Baralt, E.; Lukehart, C. M. Inorg. Chem. 1990, 29, 2870.
(17) Pregosin, P. S.; Kunz, R. W. In 31P and 13C NMR of Transition
Metal Phosphine Complexes; Diehl, P., Fluck, E., Kosfield, R., Eds.;
Springer-Verlag: New York, 1979; Vol. 16.
(18) (a) Bender, R.; Braunstein, P.; Tiripicchio, A.; Tiripicchio-
Camellini, M. J . Chem. Soc., Chem. Commun. 1984, 42. (b) Goodfellow,
R. J .; Herbert, I. R.; Orpen, A. G. J . Chem. Soc., Chem. Commun. 1983,
1386.

Diplatinum µ-Phenylethenylidene Complexes
Organometallics, Vol. 15, No. 3, 1996 1017
Sch em e 2
between cis-[Pt(C6F5)2(CO)(THF)] and platinum bis-
(alkynyl) complexes12) followed by isomerization to the
cis,cis isomer and cis 1,2 addition of the Pt-H bond
across the C-C triple bond, the last steps being similar
to those proposed for the formation of the first example
of this type of complex, [(PhCtC)(PEt3)2Pt(µ-CdCHPh)-
Pt(PEt3)2][BF4].11a
Since one of the main interests in this type of
dinuclear compound containing µ-hydrocarbyl ligands
is justified principally by their posible chemical behavior
at the bridging ligand, we decided to examine the
chemical reactivity of 1, in an attempt to induce (a)
simple carbonyl-phosphine exchange, (b) carbon-
carbon coupling at the µ-vinylidene ligand, and (c)
addition to the carbon-carbon double bond. Complex
1 was treated separately with triphenylphosphine,
phenylacetylene, and thiophenol. While no reaction was
detected between 1 and phenylacetylene (room temper-
ature, excess), compound 1 did react with PPh3 or PhSH
to give the new products 2 and 3 (Scheme 2), respec-
tively.
F igu r e 2. (a) Top: View of the structure of complex cis,cis-
[(PPh3)(C6F5)2Pt(µ-η1:η3-CHPhCCO)Pt(PPh3)2], 2, with the
atom-numbering scheme. (b) Bottom: Schematic view of
the central core of complex 2 with bond lengths in Å.
practically coplanar with the C(9)-C(1)-C(2) fragment
[deviation 0.136(1) Å], is only σ bonded to the central
carbon atom C(1). The Pt(1)-C(1) distance [2.07(2) Å]
is identical, within the experimental error, to the other
two Pt(1)-C(C6F5) [Pt(1)-C(10) 2.08(2) Å and Pt(1)-
C(16) 2.05(2) Å] bond distances. Pt(2) is unsymmetri-
cally η3-bonded to the three carbon atoms of the
hydrocarbon fragment, the Pt(2)-C(2) bond length
[2.13(2) Å] being shorter than the Pt(2)-C(1) [2.26(2)
Å] and Pt(2)-C(9) [2.34(2) Å] distances. The C-C
distances and the angle at C(1) [C(2)-C(1)-C(9) 115(2)°]
are similar to those formed in η3-allyl-Pt systems.19 In
addition, the C(9)-O(1) bond length [1.15(2) Å] and the
C(1)-C(9)-O(1) angle [162(2)°] are similar to those
reported for µ2,η1-ketenyl complexes.20 All these data
suggest that the ligand is bonded to Pt(2) in a η3-allylic
form (see Scheme 2). The oxygen atom is practically
coplanar with the central fragment C(9)-C(1)-C(2)
[deviation 0.28(1) Å], and the Cipso carbon atom of the
phenyl group C(3) deviates 0.88(2) Å. The two Pt(2)-
P(PPh3) distances are different [Pt(2)-P(2) 2.325(5) Å
and Pt(2)-P(3) 2.291(5) Å], thus reflecting the asym-
Rea ction w ith P P h 3. When an orange solution of
1 in CH2Cl2 was treated with PPh3 (molar ratio 1:1),
the color of the solution gradually turned yellow.
Partial evaporation and addition of ethanol afforded
yellow crystals of a compound, 2 (41% yield), which
according to the elemental analysis corresponds appar-
ently to an 1:1 adduct of the starting complex, 1, and
PPh3. The IR spectrum revealed the presence of a new
strong and broad absorption at 1885 cm-1. The pos-
sibility that this was due to a carbonyl which had linked
to the vinylidene ligand led us to carry out an X-ray
diffraction study, which established that this was actu-
ally the case. The structure of 2 is presented in Figure
2a, with the atom-numbering scheme. Figure 2b pro-
vides a schematic view showing the central expanded
unsaturated hydrocarbon fragment. Crystallographic
data are collected in Table 1, and selected bond dis-
tances and angles are listed in Table 2.
The most interesting feature of this molecule is the
presence of the new benzylideneketene bridging ligand
µ-CHPhCCO, formed by a formal reductive coupling
between the bridging vinylidene and the CO ligand. This
new bridging ligand is connecting two separated plati-
num moieties “Pt(1)(C6F5)2(PPh3)” and “Pt(2)(PPh3)2” via
the three carbon atoms C(9), C(1), and C(2). Pt(1),
(19) Hartley, F. R. Comprehensive Organometallic Chemistry;
Pergamon: Oxford, U.K., 1982; Vol. 6, p 721 and references therein.
(20) Geoffroy, G. L.; Bassner, S. L. Adv. Organomet. Chem. 1988,
28, 1.

1018 Organometallics, Vol. 15, No. 3, 1996
Ara et al.
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t P a r a m eter s for Com p lexes 2‚1/2(n -h exa n e) a n d 3
2
3
empirical formula
fw
C78H58F10OP3Pt2
1684.33
C63H43F10OP2Pt2S
1490.15
temp
293(2) K
293(2) K
wavelength
crys system
space group
unit cell dimens
1.541 84 Å
triclinic
P1h
0.710 73 Å
monoclinic
Cc
a ) 12.668(3) Å
b ) 14.201(3) Å
c ) 20.704(4) Å
R ) 110.13(2)°
â ) 90.00(2)°
γ ) 94.59(2)°
3484.4(13) Å3
2
a ) 15.946(5) Å
b ) 24.719(6) Å
c ) 16.039(3) Å
R ) 90°
â ) 93.01(2)°
γ ) 90°
V
Z
6313(3) Å3
4
D (calcd)
abs coeff
F(000)
1.605 Mg/m3
8.654 mm-1
1650
1.568 Mg/m3
4.578 mm-1
2884
cryst size
θ range for data collcn
hkl ranges
0.14 × 0.35 × 0.36 mm
2.27-52.62°
-13 to 13, -14 to 13, 0 to 21
8262
0.28 × 0.28 × 0.45 mm
1.52-25.43°
-19 to 19, 0 to 29, 0 to 19
6183
reflcns collcd
indepdt reflcns
7981
6036
reflcns with Fo > 4σ(Fo)
refinement method
data/restraints/params
goodness-of-fit on F2
R indices [Fo > 4σ(Fo)]a
R indices (all data)a
weighting params g1, g2
mean and max |shift/esd|, final cycle
largest diff peak and hole
absolute struct param
5276
5120
full-matrix l.s. on F2
7981/9/804
full-matrix l.s. on F2
6030/18/706
1.027
0.994
R1 ) 0.0780, wR2 ) 0.1940
R1 ) 0.1137, wR2 ) 0.2134
0.1415, 0.00
0.003, 0.056
2.089 and -2.563 e/Å3
R1 ) 0.0409, wR2 ) 0.0878
R1 ) 0.0540, wR2 ) 0.1029
0.0486, 0.00
0.000, 0.001
0.882 and -1.036 e/Å3
0.006(10)
a
2
R1 ) ∑(|Fo| - |Fc|)/∑|Fo|; wR2 ) [∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2
.
Goodness-of-fit ) [∑w(|Fo| - |Fc|)2/(Nobs - Nparam)]1/2
.
w ) [σ2(|Fo|) +
(g1P)2 + g2P]-1; P ) [max(Fo2;0) + 2Fc2]/3.
Ta ble 2. Selected Bon d Dista n ces (Å) a n d An gles
been formulated as containing a mangana-trimethyl-
ene-methane ligand bonded to an “Fe(CO)3” group.21
(d eg) for 2‚1/2(n -h exa n e)
Pt(2)-C(1)
Pt(2)-C(9)
Pt(2)-P(2)
Pt(1)-C(10)
Pt(1)-P(1)
C(1)-C(9)
C(9)-O(1)
2.26(2)
2.34(2)
2.325(5)
2.08(2)
2.296(5)
1.47(3)
1.15(2)
Pt(2)-C(2)
Pt(2)-P(3)
Pt(1)-C(1)
Pt(1)-C(16)
C(1)-C(2)
C(2)-C(3)
2.13(2)
2.291(5)
2.07(2)
2.05(2)
1.42(3)
1.40(3)
The overall reaction between 1 and PPh3 involves
addition of PPh3 ligand and insertion of CO into the
µ-vinylidene ligand to produce a benzylideneketene
ligand. The conversion of vinylidene to ketene is
noteworthy in two additional respects. There are many
examples of carbonylation (or insertion) of terminal
carbene and carbyne ligands affording ketene and
ketenyl complexes, in many cases promoted by strongly
nucleophilic phosphines.20,22 This well-known process
has utility in organic synthesis23 and has also been
pointed out to be a key step of C-C bond formation in
the hydrogenation of carbon monoxide to oxygenated
compounds.23b,24 However, the insertion of CO into a
carbene bridging ligand is a rare process and the cases
reported involve carbonylation or insertion of CO into
a µ-methylene (µ-CH2) group.20,25 As far as we know,
there is only one report in the literature of insertion of
C(1)-Pt(2)-C(2)
C(2)-Pt(2)-C(9)
C(2)-Pt(2)-P(3)
C(1)-Pt(2)-P(2)
C(9)-Pt(2)-P(2)
C(1)-Pt(1)-C(10)
C(10)-Pt(1)-C(16)
C(10)-Pt(1)-P(1)
Pt(2)-C(1)-Pt(1)
Pt(1)-C(1)-C(2)
Pt(1)-C(1)-C(9)
Pt(2)-C(2)-C(3)
Pt(2)-C(9)-C(1)
C(1)-C(9)-O(1)
37.7(7)
65.7(6)
97.8(5)
125.1(5)
94.3(4)
91.1(8)
83.5(8)
169.2(6)
124.8(9)
130(2)
C(1)-Pt(2)-C(9)
C(1)-Pt(2)-P(3)
C(9)-Pt(2)-P(3)
C(2)-Pt(2)-P(2)
P(3)-Pt(2)-P(2)
37.2(7)
133.1(5)
158.5(4)
160.0(5)
101.3(2)
C(1)-Pt(1)-C(16) 174.3(8)
C(1)-Pt(1)-P(1)
C(16)-Pt(1)-P(1)
Pt(2)-C(1)-C(2)
Pt(2)-C(1)-C(9)
93.3(6)
91.7(6)
66.1(11)
74.7(10)
115(2)
115.8(13) C(2)-C(1)-C(9)
115.5(14) C(1)-C(2)-C(3)
68.1(10) Pt(2)-C(9)-O(1)
162(2)
128(2)
130.0(13)
(21) Andrianov, V. G.; Struchkov, Yu. T.; Kolobova, N. E.; Antonova,
A. B.; Obezyuk, N. S. J . Organomet. Chem 1976, 122, C33.
(22) (a) Mayr, A.; Bastos, C. M. Prog. Inorg. Chem. 1992, 40, 1. (b)
Mayr, A.; Lee, T. Y.; Kjelsberg, M. A.; Lee, K. S. Organometallics 1994,
13, 2512. (c) Mayr, A. Comments Inorg. Chem. 1990, 10, 227.
(23) (a) Anderson, B. A.; Wulff, W. D. J . Am. Chem. Soc. 1990, 112,
8615. (b) Mitsudo, T.; Ishihara, A.; Kodokura, M.; Watanabe, Y.
Organometallics 1986, 5, 238.
(24) (a) Stevens, A. E.; Beauchamp, J . L. J . Am. Chem. Soc. 1978,
100, 2584. (b) Muetterties, E. L.; Stein, J . Chem. Rev. 1979, 79, 479.
(c) Henrici-Olive´, G.; Olive´, S. Angew. Chem., Int. Ed. Engl. 1976, 15,
136.
(25) (a) Chen, M. C.; Tsai, Y. J .; Chen, C. T.; Lin, Y. C.; Tseng, T.
W.; Lee, G. H.; Wang, Y. Organometallics 1991, 10, 378 and references
therein. (b) Ozawa, F.; Park, J . W.; Mackenzie, P. B.; Schaefer, W. P.;
Henling, L. M.; Grubbs, R. H. J . Am. Chem. Soc. 1989, 111, 1319. (c)
Nuccianore, D.; Taylor, N. J .; Carty, A. J .; Tiripicchio, A.; Tiripicchio-
Camellini, M.; Sappa, E. Organometallics 1988, 7, 118 and references
given therein.
metry of the central hydrocarbon skeleton. The relative
disposition of the C(9)-C(1)-C(2) fragment is such that
the dihedral angles with the Pt(2)P(2)P(3) moiety and
the coordination plane of Pt(1) [Pt(1)-P(1)-C(16)-
C(10)-C(1)] are 121(1) and 139(1)°, respectively. The
dihedral angle formed by the Pt(2)P(2)P(3) unit and the
coordination plane of Pt(1) is 77.6(3)°. The long Pt(1)-
Pt(2) distance (3.836 Å) indicates the absence of metal-
metal bond.
The resulting unsaturated bridging ligand in 2 is very
unusual. To our knowledge, the most closely related
compound is the heterodinuclear complex [(CO)2CpMn-
{µ-C(CO)CHPh}Fe(CO)3], formed by the treatment of
[MnCp(CO)2(CdCHPh)] with [Fe2(CO)9], which has

Diplatinum µ-Phenylethenylidene Complexes
Organometallics, Vol. 15, No. 3, 1996 1019
CO into a µ-vinylidene bridging ligand.26 However, in
this case, both the µ-CCH2 derivative and the methyl-
eneketene µ-CH2CCO complex exist in solution as a
mixture of two isomers in equilibrium.26 On the other
hand, ketene20,27 and vinylidene4 ligands have been
suggested as potential intermediates in CO reduction
processes; therefore, their interconversion is relevant.
Although there are several reports28 showing the con-
version of a free ketene to a µ-vinylidene, observation
of the reverse process has not been reported.29
The NMR spectra of complex 2 in CDCl3 are consis-
tent with the structure found in the solid state. Thus,
the 19F NMR spectrum displays four o-, two p-, and four
m- fluorine resonances as expected for the five inequiva-
lent fluorine atoms in each one of the two nonequivalent
C6F5 rings. The 31P NMR spectrum exhibits only two
resonances, but the intensity and pattern of the 195Pt
satellites of one of them indicates that two nonequiva-
lent phosphorous nuclei have coincidental chemical
shifts (δ 27.2 ppm, s, 1J (Pt-P) ) 3958 Hz, 1P; 15.1 ppm,
1
s, broad, J (Pt-P) ) 2546 and 3960 Hz, 2P).
The 1H NMR spectrum of 2 shows, in addition to
several complex resonances in the 7.5-6.6 ppm range
(see Experimental Section), two doublets at high field
(δ 5.12 ppm, J ) 7.3 Hz, 1J (Pt-H) ) 43.6 Hz; 5.58 ppm,
J ) 7.3 Hz) which can be assigned to the benzylenic
proton and to one o-phenyl proton of the CHPh frag-
ment. The resonance of this o-phenyl proton appears
at much higher field than that expected for a typical
phenyl proton. This anomalous shielding could be
attributed to the position of the o-proton just above the
aromatic ring [C(70)-C(75)] of one of the phenyl groups
of the PPh3 ligands [distance H(4)-centroid of the ring
) 2.842 Å].
Rea ction w ith P h SH. A particularly interesting
reaction of complex 1, which is unprecedented for
µ-vinylidene complexes, is the addition reaction ob-
served with thiophenol. Complex 1 (0.1 mmol) is
dissolved in neat PhSH (2 mL) to give immediatelly a
pale yellow solution. Addition of n-hexane produces the
precipitation of a yellow solid 3 (Scheme 2). Recrystal-
lization from diethyl ether gives pale-yellow crystals of
3, which were identified by elemental analysis as the
1:1 adduct. Similar results were obtained by treating
1 with 1 equiv of PhSH. A single-crystal diffraction
analysis showed the presence of a (benzylthiophenoxy)-
methylene bridging ligand formed by the addition of
PhSH to the carbon-carbon double bond of the µ-vi-
nylidene ligand in 1. Figure 3a shows a drawing of the
molecular structure of 2, and Figure 3b provides a
schematic view of the central bridging ligand. Crystal-
lographic data are collected in Table 1, and selected
bond distances and angles are listed in Table 3. Within
the (benzylthiophenoxy)methylene ligand, the bond
F igu r e 3. (a) Top: View of the structure of complex cis,cis-
[(P P h 3)2P t {µ-η2(C,S ):η1(C)-C(SP h )(CH2P h )}P t (C6F 5)2-
(CO)], 3, with the atom-numbering scheme. (b) Bottom:
Schematic view of the central core of complex 3 with bond
lengths in Å.
Ta ble 3. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for 3
Pt(1)-C(1)
Pt(1)-C(13)
Pt(2)-S(1)
Pt(2)-P(2)
S(1)-C(14)
P(1)-C(28)
P(1)-C(40)
P(2)-C(52)
O(1)-C(13)
C(15)-C(16)
2.10(2)
1.88(2)
Pt(1)-C(7)
Pt(1)-C(14)
Pt(2)-P(1)
Pt(2)-C(14)
S(1)-C(22)
P(1)-C(34)
P(2)-C(46)
P(2)-C(58)
C(14)-C(15)
2.07(2)
2.139(14)
2.280(4)
2.137(12)
1.79(2)
1.799(13)
1.86(2)
2.310(3)
2.333(4)
1.805(14)
1.822(14)
1.83(2)
1.84(2)
1.12(2)
1.54(2)
1.841(13)
1.52(2)
C(1)-Pt(1)-C(7)
C(7)-Pt(1)-C(13)
C(7)-Pt(1)-C(14)
S(1)-Pt(2)-P(1)
P(1)-Pt(2)-P(2)
P(1)-Pt(2)-C(14)
Pt(2)-S(1)-C(14)
87.5(6)
171.3(7)
95.8(6)
C(1)-Pt(1)-C(13)
84.8(7)
C(1)-Pt(1)-C(14) 173.0(6)
C(13)-Pt(1)-C(14) 92.3(7)
151.14(13) S(1)-Pt(2)-P(2)
101.78(13)
47.7(4)
106.45(13) S(1)-Pt(2)-C(14)
104.7(4)
61.1(4)
P(2)-Pt(2)-C(14) 148.8(4)
Pt(2)-S(1)-C(22) 104.9(6)
Pt(1)-C(13)-O(1) 174(2)
Pt(1)-C(14)-S(1) 110.9(7)
Pt(1)-C(14)-C(15) 113.8(9)
S(1)-C(14)-C(15) 120.9(11)
C(14)-S(1)-C(22) 109.6(8)
(26) Birk, R.; Berke, H.; Huttner, G.; Zsolnai, L. Chem. Ber. 1988,
121, 471.
Pt(1)-C(14)-Pt(2) 110.3(6)
Pt(2)-C(14)-S(1)
Pt(2)-C(14)-C(15) 123.0(9)
C(14)-C(15)-C(16) 115.8(13)
71.2(5)
(27) Loggenberg, P. M.; Carlton, L.; Copperthwaite, R. G.; Hutch-
ings, G. J . J . Chem. Soc., Chem. Commun. 1987, 541.
(28) (a) Mills, O. S.; Redhouse, A. D. J . Chem. Soc. A 1968, 1282.
(b) Young, D. A. Inorg. Chem. 1985, 24, 1492. See also: (c) Kreissl, F.
R.; Eberl, K.; Uedelhoven, W. Angew. Chem., Int. Ed. Engl. 1978, 17,
860. (d) Eberl, K.; Uedelhoven, W.; Wolfgruber, W.; Kreissl, F. R. Chem.
Ber. 1982, 115, 504. (e) Herrman, W. A.; Weber, C.; Ziegler, M. L.;
Serhadli, O. J . Organomet. Chem. 1985, 297, 245.
(29) There is a recent report showing the interconversion between
a bound ketene ligand and a terminal vinylidene group at a niobium
center: Fermin, M. C.; Bruno, J . W. J . Am. Chem. Soc. 1993, 115,
7511.
lengths S-C [S(1)-C(14) 1.805(14) Å and S(1)-C(22)
1.79(2) Å] and the C(22)-S(1)-C(14) angle [109.6(8)°]
are typical of sulfonium organic salts30 and, moreover,
(30) Perozzi, E. F.; Paul, I. C. In Chemistry of the Sulfonium Group;
Stirling, C. J . M., Patai, S., Eds.; Wiley: New York, 1981; p 15.

1020 Organometallics, Vol. 15, No. 3, 1996
Ara et al.
the C(14)-C(15) bond length of 1.52(2) Å is as expected
for a C-C single bond. This ligand connects the two
original organometallic fragments “cis-Pt(1)(C6F5)2(CO)”
and “Pt(2)(PPh3)2” present in 1 (Pt(1)‚‚‚Pt(2) ) 4.11 Å),
adopting a µ-σ(C):η2(C,S) bonding mode. Thus, the
alkylidene carbon, C(14), is bonded to both platinum
atoms with identical bond lengths, within experimental
error [Pt(1)-C(14) 2.139(14) Å; Pt(2)-C(14) 2.137(12)
Å], and similar to those observed in binuclear hetero-
platinum complexes containing µ-alkylidene ligands.31
The C(15) and the S(1) atoms of the respective benzyl
and thiophenoxy groups complete a distorted tetrahe-
dral coordination on the alkylidene C(14) atom within
which the angles vary from 71.2(5)° [Pt(2)-C(14)-S(1)]
to 123.0(9)° [Pt(2)-C(14)-C(15)]. In addition, the sulfur
atom is also bonded to Pt(2) yielding a platinathiirane
cycle with a Pt(2)-S(1) bond distance [2.310(3) Å]
similar to those found in other compounds with Pt-S
bonds.32
appears as a well-resolved doublet at 3.54 ppm (J (H-
H) ) 17 Hz) and clearly displays a large value of the
3J (Pt-H) of approximately 70 Hz, and the other appears
as a doublet of doublets centered at 2.82 ppm (J (H-H)
4
) 17 Hz and J (P-H) ) 5.4 Hz) due, probably, to a large
distance coupling with P(2). The 31P NMR spectrum
exhibits the expected two signals. The peak at 19.7 ppm
1
with the larger J (Pt-P(1)) coupling constant (5055 Hz)
can be assigned to the PPh3 ligand trans to the sulfur
atom [P(1)], and the peak at 19.9 ppm with the smaller
1J (Pt-P(2)) coupling constant, to the PPh3 ligand trans
to the µ-alkylidene carbon atom C(14).
The 19F NMR spectrum of 3, at room temperature,
shows a similar pattern to that observed for the starting
complex 1 at low temperature (-50 °C). It shows the
expected five signals (2 o-F, p-F, and 2 m-F; see
Experimental Section) for a rigid conformation of one
of the two C6F5 ligands. In this complex, examination
of Figure 3 suggests that the C6F5 group cis to the
bridging ligand is the most crowded and, probably, the
rotation of this ring around the Pt-C bond is hindered.
The remaining three signals (2:1:2) can be assigned to
the less crowded C6F5 group cis to the CO ligand, and
the observed pattern could be explained by assuming
the rotation of this ring around the Pt-C bond. By a
lowering of the temperature to -50 °C, the o-F and m-F
resonances of this C6F5 ring only broaden, but they do
not split in the expected two o-F and two m-F signals.
This reaction merits further consideration. MO cal-
culations predict that electrophilic addition on a diplati-
num symmetrical µ-vinylidene complex is frontier-
orbital-controlled, which should therefore undergo
electrophilic Câ attack.10 In this respect, the formation
of 3 from 1 and PhSH could be rationalized as a simple
electrophilic addition to the Câ carbon atom of the
vinylidene group in 1 and concomitant elimination of
the formal Pt(1)fPt(2) Lewis-base interaction by the
coordination of the sulfur atom to Pt(2).
It should be noted that both the alkylidene carbon
atom C(14) and the sulfur atom S(1) are chiral centers
and are of opposite configuration with both the SR and
RS enantiomers present in the unit cell. The enanti-
omer drawn in Figure 4 has the S configuration about
C(14) and R about S(1).
The Pt(2) atom completes its coordination sphere with
two PPh3 ligands. The shorter Pt(2)-P(1) distance
[2.280(4) Å] is trans to the sulfur atom, and the longer
Pt(2)-P(2) distance [2.333(4) Å] is trans to the alkyli-
dene carbon atom C(14). These differences are compa-
rable to those reported in complexes [Pt(PEt3)2(DHT-
H)][PF6],32a {Pd(PPh3)Cl[S(Me)CH2]},33a and {(PPh3)2-
Pd[S(Me)CH2]}[PF6],33b in which the M-P bond -trans
to the carbon atom is longer than the M-P bond trans
to the sulfur atom, and have been interpreted in terms
of a stronger trans influence for carbon than for sulfur
atoms.34 The angle S(1)-Pt(2)-C(14) [47.7(4)°], similar
to those of other three-membered (M-S-C) metallacy-
clic complexes,33,35 is considerably smaller than the
P(1)-Pt(2)-P(2) angle of 106.45(13)°, indicating a dis-
torted square planar coordination for Pt(2). The dihe-
dral angle between the S(1)-Pt(2)-C(14) and the Pt(2)-
P(1)-P(2) planes is 10.8(3)°. However, the coordination
around the platinum atom Pt(1) is less distorted and
the dihedral angle between Pt(1)-C(1)-C(7) and Pt(1)-
C(13)-C(14) planes is only 7.3(7)°. Finally, the dihedral
angle formed by the best least-square planes around
each platinum environment is 104.2(3)°.
Con clu sion s
The present study extends knowledge on the chem-
istry of µ-vinylidene complexes. We have demostrated
that the synthesis of a new neutral vinylidene-bridged
dinuclear platinum complex [(OC)(C6F5)2Pt(µ-CdCHPh)-
Pt(PPh3)2], 1, is posible through a simple reaction
between [cis-Pt(C6F5)2(CO)(THF)] and the alkynyl-
hydride mononuclear complex trans-[PtH(CtCPh)-
(PPh3)2], supplementing those previously reported for
Lukehart et al.11 This complex provides the chance to
study the influence of the nature of the ligands at the
platinum centers on the reactivity of such complexes.
It has been reported that the cationic [Pt2(µ-CdCHPh)-
(CtCPh)(PEt3)4](BF4), 4, reacts thermally or photo-
chemically with halide or pseudohalide salts to form
similar neutral compounds [Pt2(µ-CdCHPh)(CtCPh)-
(PEt3)2X], which further react with a protic acid and a
second 1 equiv of nucleophile to give the neutral [Pt2-
(µ-CdCHPh)(PEt3)3X2] compounds by loss of phenyl-
acetylene.13 Very interesting is the unusual C-C
reaction coupling of 4 with PhCtCPh, under photolysis,
to form a cationic diplatinum µ-η1:η3-butadienediyl
complex.3m We have demonstrated that the simple
µ-phenylethenylidene complex 1 shows some novel
properties. Thus, reaction with PPh3, under mild condi-
tions, induces an unprecedent C-C coupling of the CO
In accord with the X-ray structure of complex 3, the
1H NMR spectrum shows, in addition to aromatic
protons due to phenyl rings, an AB splitting pattern for
the methylene protons of the benzyl group, which are
nonequivalent (diastereotopic) due to the chirality of the
quaternary carbon, C(14). One of the methylene signals
(31) Ozawa, F.; Park, J . W.; Mackenzie, P. B.; Schaefer, W. P.;
Henling, L. M.; Grubbs, R. M. J . Am. Chem. Soc. 1989, 1319.
(32) (a) Glavee, G. N.; Daniels, L. M.; Angelici, R. J . Organometallics
1989, 8, 1856. (b) Cartner, A. M.; Fawcett, J .; Henderson, W.; Kemmit,
R. D. W.; McKenna, P.; Russell, D. R. J . Chem. Soc., Dalton Trans.
1993, 3755. (c) Uso´n, R.; Fornie´s, J .; Uso´n, M. A.; Toma´s, M.; Iba´n˜ez,
M. A. J . Chem. Soc., Dalton Trans. 1994, 401. (d) Mitchell, K. A.;
Streveler, K. C.; J ensen, C. M. Inorg. Chem. 1993, 32, 2608.
(33) (a) Miki, K.; Kay, Y.; Yasuoka, N.; Nassai, N. J . Organomet.
Chem. 1977, 135, 53. (b) Miki, K.; Kay, Y.; Yasuoka, N.; Kassai, N.
Bull. Chem. Soc. J pn. 1981, 54, 3639.
(34) (a) Appleton, T. G.; Clark, H. C.; Manzer, L. E. Coord. Chem.
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(35) Miller, D. C.; Angelici, R. J . Organometallics 1991, 10, 89.

Diplatinum µ-Phenylethenylidene Complexes
Organometallics, Vol. 15, No. 3, 1996 1021
1J (Pt-P) ) 3960 and 2546 Hz). 19F NMR (CD2Cl2, 16 °C): δ
ligand and the vinylidene moiety allowing the synthesis
of the first µ-η1:η3 benzylidenketene dinuclear platinum
complex 2. On the other hand, thiophenol have been
successfully incorporated into complex 1 via simple
addition to the carbon-carbon double bond of the
µ-CdCHPh. This addition increases the complexity of
the ligand that bridges the metal centers, giving a
dinuclear platinum complex which contains a µ-η2(C,S):
η1(C) (benzylthiophenoxy)methylene bridging ligand.
3
3
-113.17 (1 F, J (Pt-o-F) ) 353 Hz), -115.05 (1F, J (Pt-o-F)
) 347 Hz), -116.48 (1 F, 3J Pt-o-F ) 373 Hz), -116.95 (1 F,
3J Pt-o-F ) 361 Hz), (m, o-F), -162.47 (1F), -164.93 (1F), (t,
p-F), -162.07 (1F); -163.22 (1F), -164.18 (1F), -165.19 (1F),
(m, m-F). 13C NMR (CDCl3): δ 147-137 (C6F5), 125.3-134.1
(aromatic).
P r ep a r a t ion of cis,cis-[(P P h 3)2P t {µ-η2(C,S):η1(C)-C-
(SP h )(CH2P h )}P t(C6F 5)2(CO)] (3). Meth od a . A mixture
of 1 (0.14 g, 0.1 mmol) and 2 mL of PhSH was stirred at room
temperature for 4 h. Then, n-hexane (10 mL) was added to
the resulting yellow solution, causing the precipitation of a
yellow solid, which was recrystallized from diethyl ether
(yellow crystals, 36% yield). Anal. Calcd for C63F10H42OP2-
Pt2S: C, 50.81; H, 2.84; S, 2.15. Found: C, 51.22; H, 3.26; S,
Exp er im en ta l Section
Gen er a l Meth od s. Solvents were dried and purified by
known procedures and distilled prior to use. Elemental
analyses were performed with a Perkin-Elmer 240 microana-
lyzer. 1H, 13C, 31P{1H}, and 19F NMR spectra were recorded
on a Brucker ARX 300 spectrometer. Chemical shifts are given
in ppm relative to external standars [SiMe4, H3PO4 (85%), and
CFCl3]. Infrared spectra were run on a Perkin-Elmer 883
spectrometer using Nujol mulls between polyethylene sheets.
Mass spectra were recorded on a VG Autospec spectrometer.
The starting materials cis-[Pt(C6F5)2(CO)(THF)]14b and trans-
[Pt(CtCPh)H(PPh3)2]36 were prepared by published methods.
14a
1.99. IR (Nujol, cm-1): ν(CO) 2064 (vs); ν(C6F5)x-sens 791 (m),
778 (m). EI-MS: molecular peak not observed, m/z 1321 [M
- C6F5] (3%), 719 [Pt(PPh3)2]+ (100%). 1H NMR (CDCl3, 16
°C): δ 7.61, 7.32, 7.08 (m, 40H, PPh3 SPh, CH2Ph); 3.54 (d,
2
3
1H, CH2, J (H-H) ) 17 Hz, J (Pt-H) ) 70 Hz); 2.82 (dd, 1H,
CH2, 2J (H-H) ) 17 Hz, 4J (P-H) ) 5.4 Hz). 31P NMR (CDCl3,
16 °C): δ 19.87 (s, 1P, 1J (Pt-P) ) 2863 Hz); 19.69 (s, 1P,
1J (Pt-P) ) 5055 Hz). 19F NMR (CDCl3, 16 °C): δ -111.82
(1F, 3J (Pt-o-F) ) 427 Hz), -116.96 (1F, 3J (Pt-o-F) ) 358 Hz),
-117.46 (2F, 3J (Pt-o-F) ) 279 Hz), (m, o-F), -162.33 (1F),
-162.69 (1F), (t, p-F), -163.60 (1F), -164.54 (2F), -165.22
(1F), (m, m-F). 13C NMR (CDCl3): δ 153-135 (C6F5), 125.1-
134.2 (aromatic), 49.9 (this signal could be tentatively assigned
to the benzylic carbon CH2).
P r ep a r a tion of [(OC)(C6F 5)2P t(µ-CdCHP h )P t(P P h 3)2]
(1). To a CH2Cl2 solution of trans-[Pt(CtCPh)H(PPh3)2] (0.20
g, 0.24 mmol) was added, under N2, 0.15 g (0.24 mmol) of cis-
[Pt(C6F5)2(CO)(THF)], resulting in an immediate color change
of the solution from very pale yellow to deep orange. The
mixture was stirred for ca. 15 h, and the solution was
concentrated to small volume (∼4 mL). Addition of ethanol
(2 mL) yielded 1 (55%) as an orange solid. Anal. Calcd for
Meth od b. To an orange solution of 1 (0.13 g, 0.09 mmol)
in CH2Cl2 (10 mL) was added 10 µL (0.09 mmol) of PhSH to
give, immediately, a pale yellow solution, which was stirred
for 1 h. Evaporation of the solution to dryness and treatment
with n-hexane (∼5 mL) afforded 3 in 64% yield.
C
57F10H36OP2Pt2: C, 49.69; H, 2.63. Found: C, 49.78; H, 2.60.
14a
IR (Nujol, cm-1): ν(CO) 2083 (vs), ν(C6F5)x-sens 807 (m), 795
Cr ysta l Str u ctu r e Deter m in a tion of cis,cis-[(P P h 3)-
(C6F 5)2P t(µ-CHP h CCO)P t(P P h 3)2] (2) a n d cis,cis-[(P P h 3)2-
P t{µ-η2(C,S):η1(C)-C(SP h )(CH2P h )}P t(C6F5)2(CO)] (3). Suit-
able crystals of 2 and 3 for X-ray studies were obtained by
slow diffusion at room temperature of n-hexane into an acetone
solution of 2 and 3, respectively. Data were purchased from
Crystalytics Co.
(s). EI-MS: m/z 1378 [M]+ (4%), 719 [Pt(PPh3)2]+ (100%). H
1
NMR (CDCl3, 16 °C): δ 7.38-7.15 (m, 35H, PPh3, Ph), 5.75
4
(dd, CdCH, J P-H ) 26.3 and 8.2 Hz). 31P NMR (CDCl3, 16
°C): δ(PA) 35.95 (d, J (PA-PX) ) 14 Hz, 1J (Pt(2)-PA) ) 5534
Hz, 2J (Pt(1)-PA) ) 344 Hz), δ(PX) 31.17 (d, J (PA-PX) ) 14 Hz,
1J (Pt(2)-PX) ) 2593 Hz, 2J (Pt(1)-PA) not resolved). 19F NMR
(CDCl3, -50 °C): δ -109.5 (1 F, 3J (Pt-o-F) ) 395 Hz), -114.7
(2F, 3J (Pt-o-F) ) 258 Hz), -115.7 (1F, 3J (Pt-o-F) ) 296 Hz),
(d, o-F), -158.8 (1F), -161.5 (1F), (t, p-F), -162.7 (2F), -164.0
Com p lex 2. A yellow crystal of 0.14 × 0.35 × 0.36 mm
was sealed inside a thin-walled glass capillary with epoxy and
mounted on a four-circle Nicolet (Siemens) autodiffractometer.
Graphite-monochromated Cu KR (λ ) 1.541 84 Å) radiation
was used. Unit cell constants were determined from 15
accurately centered reflections with 2θ > 45°. Data were
collected at room temperature by the ω-2θ scan technique and
corrected for Lorentz, polarization, absorption effects (ψ scan
method, 7 reflections, maximum and minimum transmission
factors ) 1.000 and 0.303, respectively) and for the 22% decay
that was observed during the data collection. No extinction
correction was applied. The positions of the heavy atoms were
determined from the Patterson map. The remaining atoms
were located in successive Fourier syntheses. The H atoms
of the phenyl groups were incorporated at calculated positions
through the use of a riding model in which the C-H distance
was fixed at 0.96 Å with a isotropic displacement parameter
(1F), -166.0 (1F), (m, m-F). 19F NMR (CDCl3, 20 °C):
δ
-109.98 (m br, 1F), -114.3 (d, 2F, 3J (Pt-o-F) ) 267 Hz),
-115.0 (m br, 1F), (o-F), -159.7 (1F), -162.4 (1 F), (t, p-F),
-163.5 (m, 2F), -166.0 (m br, 2F), (m-F). 19F NMR (CDCl3,
3
50 °C): δ -112.6 (m br, 2F), -113.9 (d, 2F, J (Pt-o-F) ) 270
Hz), (o-F), -159.7 (1F), -162.4 (1F), (t, p-F), -163.5 (m, 2F),
-165.7 (m br, 2F), (m-F). 13C NMR (CDCl3): only carbon
resonances in the aromatic region are observed, δ 125.3-134.3
(Ph).
P r ep a r a tion of cis,cis-[(P P h 3)(C6F 5)2P t(µ-CHP h CCO)-
P t(P P h 3)2] (2). A mixture of 1 (0.140 g, 0.1 mmol) and PPh3
(0.026 g, 0.1 mmol) in CH2Cl2 (20 mL) was stirred at room
temperature for 17 h. The resulting yellow solution was
filtered and concentrated to ∼3 mL. Addition of ethanol
caused the precipitation of 2 as a pale yellow microcrystalline
solid. Yield: 41%. Anal. Calcd for C75F10H51OP3Pt2: C, 54.88;
H, 3.13. Found: C, 54.44; H, 3.13. IR (Nujol, cm-1): ν(CO)
1.5 times larger than that of the corresponding C atom.
A
site in the crystallographic asymmetric unit was found to be
occupied by hexane, with an occupancy factor of 0.5. Loose
geometrical restraints were applied to the C-C and C‚‚‚C
distances, and no hydrogen atoms of the solvent molecules
were located. All non-hydrogen atoms except those of the
solvent were refined with anisotropic displacement param-
eters. Final R factors were R1 ) 0.0780 (for 5276 data with
Fo > 4σ(Fo)) and wR2 ) 0.2134 (for all data). There were six
peaks higher than 1 e/Å3 (2.09-1.03 e/Å3) on the final differ-
ence Fourier map, and they were located close to the platinum
atoms, without any chemical meaning. The highest hole is
-2.563 e/Å3. The high background is probably due to the poor
quality of the data: high absorption and decay.
14a
1885 (s, br), (1840 (s, br) in CH2Cl2 solution); ν(C6F5)x-sens
789 (m), 775 (m). EI-MS: molecular peak not observed, m/z
719 [Pt(PPh3)2]+ (100%). 1H NMR (CDCl3, 16 °C): δ 7.46, 7.31,
7.25, 7.05 and 6.92 (m, 46 H, Ph, PPh3 and one o-H of the
CHPh fragment), 6.69 (t, 1 p-H of CHPh), 6.56 (m, 2 m-H of
CHPh), 5.57 (d, 1H, J ) 7.6 Hz), 5.08 (d, 1 H, 2J (Pt-H) )
43.6 Hz), (benzylenic and o-H of the CHPh). 31P NMR (CDCl3,
1
16 °C): δ 27.2 (s, 1P, J (Pt-P) ) 3958 Hz), 15.07 (s, br, 2P,
(36) Furlani, A.; Licoccia, S.; Russo, M. V.; Chiesi-Villa, A.; Guastini,
C. J . Chem. Soc., Dalton Trans. 1982, 2449.

1022 Organometallics, Vol. 15, No. 3, 1996
Ara et al.
Com p lex 3. A single yellow crystal (approximate dimen-
sions 0.28 × 0.28 × 0.28 mm) was mounted on a four-circle
Nicolet (Siemens) autodiffractometer. Graphite-monochro-
mated Mo KR (λ ) 0.710 73 Å) radiation was used. Unit cell
constants were determined from 15 accurately centered reflec-
tions with 2θ > 21°. The intensity data were collected by the
ω scan techniqe at room temperatre. Six check reflections
were measured every 300 min, and no loss of intensity was
observed. Lorentz and polarization corrections were applied.
Data reduction included an absorption correction (ψ scan
method, 7 reflections, maximum and minimum transmission
factors ) 1.000 and 0.749, respectively). The positions of the
platinum atoms were determined from the Patterson map. The
remaining atoms were located in subsequent Fourier synthe-
ses. One of the phenyl rings was found to be equally
disordered over two positions, with the common Cipso atom
(C(16)). All non-hydrogen atoms, except those belonging to
the disordered phenyl ring, were refined with anisotropic
displacement parameters. Hydrogen atoms were added at
calculated positions through the use of a riding model in which
the C-H distance was fixed at 0.96 Å with the common
isotropic factor refining at 0.079(11) Å2. The final R factors
were R1 ) 0.0409 (for 5108 data with Fo > 4σ(Fo)) and wR2 )
0.1029 (for all data). The highest peak on the final difference
Fourier map was 0.882 e/Å3.
All the calculations were done on a Local Area VAX cluster
(VAX/VMS V5.5) with the commercial package SHELXTL-
PLUS37 and the SHELXL-93 program.38
Ack n ow led gm en t. We thank the Comisio´n Inter-
ministerial de Ciencia y Tecnolog´ıa (Spain) for financial
support (Project PB92-0364) and for a grant to J .R.B.
Su p p or tin g In for m a tion Ava ila ble: Tables of bond
lengths and bond angles, anisotropic displacement parameters,
and atom coordinates and U values for complexes 2 and 3 (18
pages). Ordering information is given on any current mast-
head page.
OM950891X
(37) SHELXTL-PLUS, Software Package for the Determination of
Crystal Structures, Release 4.0, Siemens Analytical X-ray Instruments,
Inc., Madison WI, 1990.
(38) Sheldrick, G. M. Shelxl-93 FORTRAN program for the refine-
ment of crystal structures from diffraction data, University of Go¨ttin-
gen, 1993 (J . Appl. Crystallogr., manuscript in preparation).