Heterobinuclear and heterotrinuclear metal μ-allenyl complexes containing platinum and one or both of iron and ruthenium. Synthesis of higher nuclearity metal complexes from mononuclear metal η1-propargyls and η1-allenyls and from binuclear metal μ-η1:η2α,β-allenyls

Article abstract of DOI:10.1021/om000205g

The reactions of Cp(CO)₂MCH₂C≡CPh with Pt(PPh₃)₄ or Pt(PPh₃)₂C₂H₄ in THF at reflux and of Cp(CO)₂MCH=C=CH₂ with Pt(PPh₃)₂C₂H₄ in THF or hexane at -78 °C to ambient temperature afforded the heterobinuclear metal μ-allenyl complexes (PPh₃)₂Pt(μ-η¹:η² _α,β-C(Ph)=C=CH₂)M(CO)Cp (M = Ru, R = Ph (1a); M = Fe, R = Ph (2a); M = Ru, R = H (1b); M = Fe, R = H (2b)). The products reacted with Ru₃(CO)₁₂ or Fe₂(CO)₉ (Ru, Fe = M′) in THF at room temperature to yield open heterotrinuclear metal μ-allenyl complexes (PPh₃)-(CO)Pt(μ₃-η¹:η ²:η²-C(R)=C=CH₂)M′(CO) ₃M(CO)Cp (M′ = M = Ru, R = H (4); M′ - Ru, M = Fe, R = H (5); M′ = Fe, M = Ru, R = Ph (6a); M′ = Fe, M = Ru, R = H (6b); M′ = M = Fe, R = H (7)), as well as M′(CO)₄PPh₃. The reaction of 1a with Fe₂(CO)₉ also afforded the CO-for-PPh₃ substitution product (PPh₃)(CO)Pt(μ-η¹:η² _α,β-C(Ph)=C=CH₂)Ru(CO)Cp (3). Treatment of the μ-allenylcarbonyl (CO)₃Fe(μ-η¹:η³-η ²-C(O)C(Ph)=C=CH₂)Ru(CO)Cp with Pt(PPh₃)₂C₂H₄ in THF at 0 °C with warming to ambient temperature gave three heterometallic products: 6a, the PPh₃-for-CO substituted (PPh₃)(CO)₂Fe(μ-η³:η ²-C(O)C(Ph)=C=CH₂)Ru(CO)Cp, and (PPh₃)₂Pt(μ₃-η¹:η ¹:η³-C(Ph)CCH₂)Ru(CO)Cp(μ ₂-CO)Fe(CO)₂ (8). All new products were characterized by a combination of IR and NMR (¹H, ¹³C{¹H}, and ³¹P{₁H}) spectroscopy, FAB mass spectrometry, and elemental analysis; the structures of 1b, 3, 6a, and 8 were elucidated by X-ray diffraction analysis. Complexes 1b and 3 each contain a Pt-Ru bond and a μ-allenyl group that is η¹ ligated to Pt and η² ligated, through the internal C=C bond, to Ru. 6a contains an open Pt-Fe-Ru metal framework, with the μ-C(Ph)=C=CH₂ ligand being attached η¹ to Pt, η² through the C(Ph)=C to Fe, and η² through the C=CH₂ to Ru. 8 is also an open, Pt-Fe-Ru bonded cluster; however, it contains an η³-allyl group ligated to Fe and metalated at CPh (Ru) and C_β (Pt). Possible mechanisms of formation of the new μ-allenylmetal complexes are presented. Complexes 1 and 2 underwent fragmentation of the binuclear framework to yield Cp(CO)₂MCH=C=CH₂ (M = Ru, Fe), Cp(CO)₂RuC(Ph)=C=CH₂, or Cp-(CO)₂FeCH₂C≡CPh, as appropriate, in addition to Pt(PPh₃)₂(CO)₂, upon treatment with CO at room temperature. The reverse of these processes can be effected by sweeping the product solutions with Ar for the three η¹-allenyl complexes, but not for Cp(CO)₂FeCH₂C=CPh.

Full text of DOI:10.1021/om000205g

Organometallics 2000, 19, 3179-3191
3179
Heter obin u clea r a n d Heter otr in u clea r Meta l µ-Allen yl
Com p lexes Con ta in in g P la tin u m a n d On e or Both of Ir on
a n d Ru th en iu m . Syn th esis of High er Nu clea r ity Meta l
Com p lexes fr om Mon on u clea r Meta l η1-P r op a r gyls a n d
η1-Allen yls a n d fr om Bin u clea r Meta l µ-η1:η2r,â-Allen yls
Richard R. Willis, Chris E. Shuchart, and Andrew Wojcicki*
Department of Chemistry, The Ohio State University, Columbus, Ohio 43210
Arnold L. Rheingold† and Brian S. Haggerty
Department of Chemistry, University of Delaware, Newark, Delaware 19711
Received March 2, 2000
The reactions of Cp(CO)2MCH2CtCPh with Pt(PPh3)4 or Pt(PPh3)2C2H4 in THF at reflux
and of Cp(CO)2MCHdCdCH2 with Pt(PPh3)2C2H4 in THF or hexane at -78 °C to ambient
temperature afforded the heterobinuclear metal µ-allenyl complexes (PPh3)2Pt(µ-η1:η2
-
R,â
C(Ph)dCdCH2)M(CO)Cp (M ) Ru, R ) Ph (1a ); M ) Fe, R ) Ph (2a ); M ) Ru, R ) H (1b);
M ) Fe, R ) H (2b)). The products reacted with Ru3(CO)12 or Fe2(CO)9 (Ru, Fe ) M′) in
THF at room temperature to yield open heterotrinuclear metal µ-allenyl complexes (PPh3)-
(CO)Pt(µ3-η1:η2:η2-C(R)dCdCH2)M′(CO)3M(CO)Cp (M′ ) M ) Ru, R ) H (4); M′ ) Ru, M )
Fe, R ) H (5); M′ ) Fe, M ) Ru, R ) Ph (6a ); M′ ) Fe, M ) Ru, R ) H (6b); M′ ) M ) Fe,
R ) H (7)), as well as M′(CO)4PPh3. The reaction of 1a with Fe2(CO)9 also afforded the CO-
for-PPh3 substitution product (PPh3)(CO)Pt(µ-η1:η2R,â-C(Ph)dCdCH2)Ru(CO)Cp (3). Treat-
ment of the µ-allenylcarbonyl (CO)3Fe(µ-η3:η2-C(O)C(Ph)dCdCH2)Ru(CO)Cp with Pt(PPh3)2C2H4
in THF at 0 °C with warming to ambient temperature gave three heterometallic products:
6a , the PPh3-for-CO substituted (PPh3)(CO)2Fe(µ-η3:η2-C(O)C(Ph)dCdCH2)Ru(CO)Cp, and
(PPh3)2Pt(µ3-η1:η1:η3-C(Ph)CCH2)Ru(CO)Cp(µ2-CO)Fe(CO)2 (8). All new products were charac-
terized by a combination of IR and NMR (1H, 13C{1H}, and 31P{1H}) spectroscopy, FAB mass
spectrometry, and elemental analysis; the structures of 1b, 3, 6a , and 8 were elucidated by
X-ray diffraction analysis. Complexes 1b and 3 each contain a Pt-Ru bond and a µ-allenyl
group that is η1 ligated to Pt and η2 ligated, through the internal CdC bond, to Ru. 6a
contains an open Pt-Fe-Ru metal framework, with the µ-C(Ph)dCdCH2 ligand being
attached η1 to Pt, η2 through the C(Ph)dC to Fe, and η2 through the CdCH2 to Ru. 8 is also
an open, Pt-Fe-Ru bonded cluster; however, it contains an η3-allyl group ligated to Fe and
metalated at CPh (Ru) and Câ (Pt). Possible mechanisms of formation of the new µ-allenyl-
metal complexes are presented. Complexes 1 and 2 underwent fragmentation of the binuclear
framework to yield Cp(CO)2MCHdCdCH2 (M ) Ru, Fe), Cp(CO)2RuC(Ph)dCdCH2, or Cp-
(CO)2FeCH2CtCPh, as appropriate, in addition to Pt(PPh3)2(CO)2, upon treatment with CO
at room temperature. The reverse of these processes can be effected by sweeping the product
solutions with Ar for the three η1-allenyl complexes, but not for Cp(CO)2FeCH2CtCPh.
In tr od u ction
ing heterometallic nuclei into close proximity and
thereby facilitating formation of metal-metal bonds.
Studies in this laboratory on reactions of transition
metal η1-propargyl and η1-allenyl complexes with metal
carbonyls have resulted in the preparation of heterobi-
nuclear and heterotrinuclear metal µ-allenyl com-
pounds, as well as other heterometallic products with
bridging hydrocarbyl ligands.1,2 This synthetic method-
ology utilizes the multiple carbon-carbon bonds of the
propargyl and allenyl as molecular templates for bring-
Applications of this methodology to binuclear metal
µ-η3:η2-allenyl/propargyl (I)3 and trinuclear metal µ3-
† To whom inquiries concerning the X-ray crystallographic work
should be addressed.
(1) Reviews: (a) Wojcicki, A.; Shuchart, C. E. Coord. Chem. Rev.
1990, 105, 35. (b) Wojcicki, A. J . Cluster Sci. 1993, 4, 59. (c) Doherty,
S.; Corrigan, J . F.; Carty, A. J .; Sappa, E. Adv. Organomet. Chem. 1995,
37, 39. (d) Metal Clusters in Chemistry; Braunstein, P., Oro, L. A.,
Raithby, P. R., Eds.; Wiley-VHC: New York, 1999; Vols. 1-3.
(2) Shuchart, C. E.; Calligaris, M.; Churchill, M. R.; Faleschini, P.;
See, R. F.; Wojcicki, A. Inorg. Chim. Acta 1996, 243, 109.
10.1021/om000205g CCC: $19.00 © 2000 American Chemical Society
Publication on Web 07/11/2000

3180 Organometallics, Vol. 19, No. 16, 2000
Willis et al.
under an atmosphere of argon by using standard procedures.11
Elemental analyses were performed by M-H-W Laboratories,
Phoenix, AZ. Chromatographic separations were effected on
columns packed with Grade III (6% H2O) alumina. Melting
points were measured on a Thomas-Hoover melting point
apparatus and are uncorrected. Infrared, NMR (1H, 13C, and
31P), and mass spectra (FAB) were obtained as previously
described.3,12
η1:η2:η2-allenyl (II)3,4 compounds containing metal car-
Ma ter ia ls. All solvents were distilled under an argon
atmosphere. Hexane was distilled from potassium, THF and
diethyl ether were distilled from Na/K alloy and benzophenone,
bonyl and cyclopentadienylmetal carbonyl groups have
already been reported. To further explore the scope of
synthetic possibilities, we endeavored to examine reac-
tions of iron and ruthenium η1-propargyl and η1-allenyl
complexes with Pt(PPh3)2C2H4 and Pt(PPh3)4. Both of
these platinum(0) compounds readily undergo ligand
dissociation and/or substitution,5 necessary for metal
binding to the η1-attached propargyl or allenyl ligand.
Furthermore, platinum forms strong metal-metal and
metal-carbon bonds6 and therefore represents an excel-
lent candidate for such nuclearity expansion reactions.
Reported herein is a full account of our studies7 on
these reactions which afforded the first examples of
heterometallic µ-η1:η2R,â-allenyl compounds (III), (PPh3)2-
Pt(µ-η1:η2R,â-C(R)dCdCH2)M(CO)Cp. Homometallic rep-
and dichloromethane was distilled from P4O10
.
Reagents were obtained from various commercial sources
and used as received, except as noted below. The compounds
Pt(PPh3)4,13 Pt(PPh3)2C2H4,14 Fe2(CO)9,15 Ru3(CO)12,16 and (CO)3-
Fe(µ-η3:η2-C(O)C(Ph)dCdCH2)Ru(CO)Cp4 were synthesized
according to the literature. Pt(PPh3)2(CO)2 was prepared
quantitatively by exposure of THF solutions of Pt(PPh3)2C2H4
to carbon monoxide atmosphere.17 The ruthenium propargyl
and allenyl complexes Cp(CO)2RuCH2CtCPh and Cp(CO)2-
RuCHdCdCH2, respectively, were prepared by literature
procedures,18 and their iron analogues Cp(CO)2FeCH2CtCPh
and Cp(CO)2FeCHdCdCH2 were synthesized by a close ad-
aptation of the literature procedure19 using Na/K alloy rather
than sodium as a reducing agent.
Rea ction s of Mon on u clea r Meta l P r op a r gyl a n d Alle-
n yl Com p lexes w ith P la tin u m (0) Rea gen ts. (i) Cp (CO)2-
Ru CH2CtCP h . To a stirred solution of Cp(CO)2RuCH2Ct
CPh (0.550 g, 1.63 mmol) in THF (100 mL) at room temperature
was added Pt(PPh3)4 (2.70 g, 2.17 mmol) as a solid. The
resulting orange solution was heated at reflux temperature
for 9 h, during which time its color turned deep red. The
solution was allowed to cool to room temperature and was
concentrated in vacuo to about 10 mL and treated with 20 mL
of hexane with stirring. It was then kept at -23 °C for 12 h to
yield yellow crystals of (PPh3)2Pt(µ-η1:η2R,â-C(Ph)dCdCH2)-
Ru(CO)Cp (1a ), which were collected by filtration. Repeated
concentration/crystallization procedures on the resultant mother
liquors afforded a total 56% yield (0.931 g) of 1a : dec pt 175
resentatives of III have been known for some time;8-10
however, they were prepared by completely different
methods.
The availability of (PPh3)2Pt(µ-η1:η2R,â-C(R)dCdCH2)M-
(CO)Cp with an uncoordinated CâdCγ bond of the
allenyl ligand presented an opportunity to study pos-
sible expansion of molecular nuclearity by reaction with
1
°C; IR (CH2Cl2) ν(CO) 1912 cm-1; H NMR (CDCl3) δ 7.9-6.5
(m, 35H, Ph), 5.43 (d, J HH ) 2.2 Hz, J PtH ) 17.8 Hz, 1H of
dCH2), 4.89 (d, J HH ) 2.2 Hz, J PtH ) 13.5 Hz, 1H of dCH2),
4.26 (s, 5H, Cp); 13C NMR (CDCl3) δ 206.6 (s, J PtC ) 48 Hz,
CO), 165.3 (s, dC)), 149.1 (s, dCPh), 137.0-124.4 (m, Ph),
97.2 (dt, J PC ) 2.3 Hz, J CH ) 160 Hz, J PtC ) 32 Hz, dCH2),
85.2 (m, Cp); 31P{1H} NMR (CDCl3) δ 23.6 (d, J PP ) 4.2 Hz,
J PtP ) 2766 Hz), 21.5 (d, J PP ) 4.2 Hz, J PtP ) 3689 Hz); MS
metal carbonyls. Indeed, compounds (PPh3)2Pt(µ-η1:η2
-
R,â
C(R)dCdCH2)M(CO)Cp were found to react with Ru3-
(CO)12 or Fe2(CO)9 to afford heterotrinuclear metal
µ-η1:η2:η2-allenyl products. All of these synthetic inves-
tigations, some reaction chemistry of the products, and
X-ray structural studies on two binuclear and two
trinuclear products comprise the content of this paper.
(FAB), 102Ru and 195Pt isotopes, m/z 1029 (M+), 1001 (M+
-
CO), 719 (Pt(PPh3)2+). Anal. Calcd for C51H42OP2PtRu: C,
59.53; H, 4.11. Found: C, 59.58; H, 3.75.
An alternative preparation of 1a involves use of Pt-
(PPh3)2C2H4 in place of Pt(PPh3)4. Thus, a solution of Cp-
(CO)2RuCH2CtCPh (0.105 g, 0.311 mmol) and Pt(PPh3)2C2H4
(0.300 g, 0.401 mmol) in 15 mL of ethylene-saturated THF was
heated at reflux temperature for 20 h. Workup was as in the
preceding procedure, except that only one crystallization was
necessary. Yield: 0.28 g (87%).
Exp er im en ta l Section
Gen er a l P r oced u r es a n d Mea su r em en ts. All reactions
and manipulations of air-sensitive compounds were carried out
(3) Young, G. H.; Raphael, M. V.; Wojcicki, A.; Calligaris, M.; Nardin,
G.; Bresciani-Pahor, N. Organometallics 1991, 10, 1934.
(4) Shuchart, C. E.; Wojcicki, A.; Calligaris, M.; Faleschini, P.;
Nardin, G. Organometallics 1994, 13, 1999.
(5) Cross, R. J . In Comprehensive Organometallic Chemistry II; Abel,
E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: Oxford, U.K.,
1995; Vol. 9, Chapter 7.
(6) (a) Al Takhin, G.; Skinner, H. A.; Zaki, A. A. J . Chem. Soc.,
Dalton Trans. 1984, 371. (b) Farrugia, L. J . Adv. Organomet. Chem.
1990, 31, 301. (c) Chetcuti, M. J . In Comprehensive Organometallic
Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.;
Pergamon: Oxford, U.K., 1995; Vol. 10, Chapter 2.
(7) Some reactions were presented in the reviews in ref 1.
(8) (a) Nucciarone, D.; Taylor, N. J .; Carty, A. J . Organometallics
1986, 5, 1179. (b) Carleton, N.; Corrigan, J . F.; Doherty, S.; Pixner,
R.; Sun, Y.; Taylor, N. J .; Carty, A. J . Organometallics 1994, 13, 4179.
(9) Seyferth, D.; Womack, G. B.; Archer, C. M.; Dewan, J . C.
Organometallics 1989, 8, 430.
(ii) Cp(CO)2FeCH2CtCP h . A solution of Cp(CO)2FeCH2Ct
CPh (0.250 g, 0.856 mmol) and Pt(PPh3)4 (1.30 g, 1.04 mmol)
(11) Shriver, D. F.; Drezdzon, M. A. The Manipulation of Air-
Sensitive Compounds, 2nd ed.; Wiley: New York, 1986.
(12) Young, G. H.; Willis, R. R.; Wojcicki, A.; Calligaris, M.;
Faleschini, P. Organometallics 1992, 11, 154.
(13) Ugo, R.; Cariati, F.; LaMonica, G. Inorg. Synth. 1971, 11, 105.
(14) Blake, D. M.; Roundhill, D. M. Inorg. Synth. 1978, 18, 120.
(15) Braye, E. H.; Hu¨bel, W. Inorg. Synth. 1966, 8, 178.
(16) Bruce, M. I.; J ensen, C. M.; J ones, N. L. Inorg. Synth. 1989,
26, 259.
(17) Sen, A.; Halpern, J . Inorg. Chem. 1980, 19, 1073.
(18) Shuchart, C. E.; Willis, R. R.; Wojcicki, A. J . Organomet. Chem.
1992, 424, 185.
(10) Doherty, S.; Elsegood, M. R. J .; Clegg, W.; Rees, N. H.; Scanlan,
T. H.; Waugh, M. Organometallics 1997, 16, 3221.
(19) Roustan, J .-L.; Cadiot, P. C. R. Acad. Sci., Ser. C 1969, 268,
734.

Metal µ-Allenyl Complexes Containing Pt
Organometallics, Vol. 19, No. 16, 2000 3181
in THF (80 mL) was heated at reflux temperature for 2 h
before the orange solid (PPh3)2Pt(µ-η1:η2R,â-C(Ph)dCdCH2)Fe-
(CO)Cp (2a ) was isolated as in the synthesis of 1a : yield 0.675
g (80%); dec pt 160 °C; IR (CH2Cl2) ν(CO) 1896 cm-1; 1H NMR
(0.085 g, 22% yield) as a red solid upon solvent removal in
vacuo: dec pt 107 °C; IR (CH2Cl2) ν(CO) 2038 (s), 2015 (m),
1
2000 (w), 1971 (s) cm-1; H NMR (CDCl3) δ 7.9-7.0 (m, 30H,
Ph), 4.96 (s, 5H, Cp), 2.66 (s, br, 1H of dCH2), 2.32 (m, 1H of
dCH2) (dCH signal masked in δ 7.9-7.0 region); 13C{1H} NMR
(CDCl3) δ 201.1 (s, RuCO’s), 200.7 (s, RuCO), 199.9 (s, PtCO),
196.9 (s, dCd), 166.6 (d, J PC ) 4.0 Hz, dCH), 89.4 (s, Cp),
44.4 (s, dCH2); 31P{1H} NMR δ 25.0 (s, J PtP ) 2840 Hz); MS
(FAB), 102Ru and 195Pt isotopes, m/z 905 (M+), consecutive loss
of 5 CO’s.
(CDCl3) δ 7.7-6.9 (m, 35H, Ph), 5.26 (d, J HH ) 2.1 Hz, J PtH
)
19.7 Hz, 1H of dCH2), 4.83 (d, J HH ) 2.1 Hz, J PtH ) 14.3 Hz,
1H of dCH2), 3.76 (s, 5H, Cp); 13C{1H} NMR (CDCl3) δ 220.4
(s, J PtC ) 8.0 Hz, CO), 173.3 (s, dCd), 149.8 (s, dCPh), 96.9
(d, J PC ) 3.5 Hz, J PtC ) 36 Hz, dCH2), 82.6 (s, Cp); 31P{1H}
NMR (CDCl3) δ 27.7 (d, J PP ) 1.0 Hz, J PtP ) 3500 Hz), 26.0
(d, J PP ) 1.0 Hz, J PtP ) 2813 Hz); MS (FAB), 195Pt isotope, m/z
984 (M+ + 1), 956 (M+ - CO + 1), 840 (M+ - CO - CH2CCPh).
Anal. Calcd for C51H42FeOP2Pt: C, 62.20; H, 4.40. Found: C,
62.41; H, 4.49.
(ii) (P P h 3)2P t(µ-η1:η2r,â-CHdCdCH2)F e(CO)Cp (2b). A
suspension of 2b (0.300 g, 0.331 mmol) and Ru3(CO)12 (0.215
g, 0.336 mmol) in hexane (30 mL) was heated at reflux
temperature for 1 h, resulting in the formation of a red
heterogeneous mixture. The contents were filtered through a
pad of Celite while still hot, and solvent was removed from
the solution to yield a red tar. The tar was dissolved in CH2-
Cl2 (3 mL) and added to a short column of alumina (10 × 5
cm) packed in hexane. Rapid elution with hexane removed
unwanted side products (such as Ru(CO)4PPh3) as an orange
band. Further elution with THF yielded a red band, which
upon removal from the column and solvent evaporation
afforded (PPh3)(CO)Pt(µ3-η1:η2:η2-CHdCdCH2)Ru(CO)3Fe(CO)-
Cp (5). The product was purified by crystallization from THF/
hexane: yield 0.095 g (34%); dec pt 97 °C; IR (CH2Cl2) ν(CO)
2036 (s), 2010 (vs), 1994 (m), 1970 (m) cm-1; 1H NMR (CDCl3)
δ 8.1-7.4 (m, 30H, Ph), 7.21 (d, J PH ) 10.0 Hz, J PtH ) 50.0
Hz, 1H, dCH), 4.49 (s, 5H, Cp), 2.75 (s, br, 1H of dCH2), 2.34
(d, J HH ) 4.0 Hz, J PtH ) 20.0 Hz, 1H of dCH2); 13C{1H} NMR
(CDCl3) δ 216.1 (s, J PtC ) 53.0 Hz, FeCO), 208.0 (s, br, RuCO’s),
199.7 (s, PtCO), 196.7 (s, dCd), 167.4 (d, J PC ) 4.0 Hz, dCH),
86.1 (s, Cp), 44.9 (s, dCH2); 31P{1H} NMR (CDCl3) δ 24.1 (J PtP
) 2854 Hz); MS (FAB), 102Ru and 195Pt isotopes, m/z 859 (M+),
consecutive loss of 5 CO’s. Anal. Calcd for C31H23FeO5PPtRu:
C, 43.37; H, 2.70. Found: C, 43.35; H, 3.08.
Rea ction s of Heter obin u clea r Meta l Allen yl Com -
p lexes w ith F e2(CO)9. (i) (P P h 3)2P t(µ-η1:η2r,â-C(P h )dCd
CH2)Ru (CO)Cp (1a ). A stirred solution of 1a (1.10 g, 1.07
mmol) in THF (100 mL) at room temperature was treated with
solid Fe2(CO)9 (0.518 g, 1.42 mmol). The color of the resulting
suspension turned red over 36 h. Solvent was removed in vacuo
to yield a red tar, which was dissolved in CH2Cl2 (2 mL), and
the resulting solution was introduced onto a column of alumina
(20 × 2 cm) packed in hexane. Elution with 4% diethyl ether
in hexane afforded a yellow band, which upon removal from
the column and evaporation of the solvent left a yellow solid,
(PPh3)(CO)Pt(µ-η1:η2R,â-C(Ph)dCdCH2)Ru(CO)Cp (3): yield
0.105 g (12%); dec pt 160 °C; IR (CH2Cl2) ν(CO) 2018 (s), 1947
(s) cm-1; 1H NMR (CDCl3) δ 8.2-7.3 (m, 20H, Ph), 5.60 (s, J PtH
) 17.7 Hz, 1H of dCH2), 5.02 (s, J PtH ) 14.3 Hz, 1H of dCH2),
4.80 (s, 5H, Cp); 13C{1H} NMR (CDCl3) δ 204.2 (s, RuCO), 193.2
(d, J PC ) 5.0 Hz, PtCO), 163.3 (d, J PC ) 5.0 Hz, dCd), 148.2
(s, dCPh), 98.4 (s, dCH2), 84.6 (s, Cp); 31P{1H} NMR (CDCl3)
δ 24.4 (s, J PtP ) 3277 Hz); MS (FAB), 102Ru and 195Pt isotopes,
m/z 795 (M+), 767 (M+ - CO), 739 (M+ - 2CO). Anal. Calcd
for C34H27O2PPtRu: C, 51.39; H, 3.42. Found: C, 51.23; H,
3.37.
(iii) Cp (CO)2Ru CHdCdCH2. To a stirred suspension of
Pt(PPh3)2C2H4 (1.58 g, 2.11 mmol) in hexane (40 mL) at -20
°C was added a solution of Cp(CO)2RuCHdCdCH2 (0.500 g,
1.91 mmol) in hexane. The resulting mixture was allowed to
warm to room temperature over 1 h. The color of the suspended
material gradually changed from white to yellow. The reaction
was complete in 2 h at room temperature as determined by
31P{1H} NMR spectroscopy. The yellow solid of (PPh3)2Pt(µ-
η1:η2R,â-CHdCdCH2)Ru(CO)Cp (1b) was collected on a frit,
washed with hexane (3 × 10 mL), and dried in vacuo: yield
1
1.58 g (87%); dec pt 160 °C; IR (CH2Cl2) ν(CO) 1912 cm-1; H
NMR (CDCl3) δ 8.0-7.2 (m, 30H, Ph), 6.61 (m, J PtH ) 33.0
Hz, 1H, dCH), 5.44 (d, J HH ) 2.5 Hz, J PtH ) 19.2 Hz, 1H of
dCH2), 4.66 (d, J HH ) 2.5 Hz, J PtH ) 15.0 Hz, 1H of dCH2),
4.52 (s, 5H, Cp); 13C NMR (CDCl3) δ 206.9 (s, J PtC ) 38.4 Hz,
CO), 168.0 (s, dCd), 136.6-126.2 (m, Ph), 114.7 (dd, J PC
84.7 Hz, J CH ) 161 Hz, J PtC ) 725 Hz, dCH), 95.6 (dt, J PC
)
)
3.1 Hz, J CH ) 160 Hz, J PtC ) 36.5 Hz, dCH2), 82.3 (m, Cp);
31P{1H} NMR (CDCl3) δ 27.7 (d, J PP ) 4.3 Hz, J PtP ) 2852 Hz),
21.8 (d, J PP ) 4.3 Hz, J PtP ) 3620 Hz); MS (FAB), 102Ru and
195Pt isotopes, m/z 953 (M+), 886 (M+ - CO - C3H3), 719 (Pt-
(PPh3)2+). Anal. Calcd for C45H38OP2PtRu: C, 56.72; H, 3.99.
Found: C, 56.74; H, 4.08.
(iv) Cp (CO)2F eCHdCdCH2. Solid Pt(PPh3)2C2H4 (1.0 g,
1.3 mmol) was added to a stirred solution of Cp(CO)2FeCHd
CdCH2 (0.33 g, 1.5 mmol) in 50 mL of THF at -15 °C. After
the solid dissolved within 30 min, the resulting orange solution
was allowed to warm to room temperature in 1 h. It was then
concentrated in vacuo to ca. 10 mL, and hexane (20 mL) was
added with vigorous stirring. The contents were cooled at -23
°C for 12 h, and the orange crystals of (PPh3)2Pt(µ-η1:η2R,â-CHd
CdCH2)Fe(CO)Cp (2b) were collected on a frit, washed with
hexane (2 × 20 mL), and dried in vacuo: yield 0.730 g (60%);
dec pt 140 °C; IR (CH2Cl2) ν(CO) 1899 cm-1; 1H NMR (CDCl3)
δ 8.1-7.2 (m, 30H, Ph), 7.03 (m, J PtH ) 36.8 Hz, 1H, dCH),
5.43 (d, J HH ) 1.0 Hz, J PtH ) 10.0 Hz, 1H of dCH2), 4.67 (d,
J HH ) 1.0 Hz, J PtH ) 10.1 Hz, 1H of dCH2), 4.05 (s, 5H, Cp);
13C{1H} NMR (CDCl3) δ 220.2 (d, J PC ) 8.6 Hz, J PtC ) 84.6
Hz, CO), 176.4 (s, dCd), 122.3 (dd, J PC ) 4.5, 80.2 Hz, J PtC
)
715 Hz, dCH), 94.3 (d, J PC ) 2.9 Hz, J PtC ) 41.7 Hz, dCH2),
79.7 (s, Cp); 31P{1H} NMR (CDCl3) δ 30.9 (d, J PP ) 1.0 Hz,
J PtP ) 2925 Hz), 27.7 (d, J PP ) 1.0 Hz, J PtP ) 3415 Hz); MS
(FAB), 195Pt isotope, m/z 908 (M+ + 1), 880 (M+ - CO + 1),
840 (M+ - CO - C3H3), 719 (Pt(PPh3)2+). Anal. Calcd for
Further elution with 15% diethyl ether in hexane yielded
orange (PPh3)(CO)Pt(µ3-η1:η2:η2-C(Ph)dCdCH2)Fe(CO)3Ru-
(CO)Cp (6a ) after evaporation of the solvent: yield 0.175 g
(17%); dec pt 180 °C; IR (CH2Cl2) ν(CO) 2025 (s), 1996 (vs),
1954 (m) cm-1; 1H NMR (CDCl3) δ 7.7-7.0 (m, 20H, Ph), 4.82
(s, 5H, Cp), 3.86 (d, J HH ) 5.1 Hz, J PtH ) 12.7 Hz, 1H of d
C
45H38FeOP2Pt: C, 59.55; H, 4.22. Found: C, 59.82; H, 4.21.
Rea ction s of Heter obin u clea r Meta l Allen yl Com -
p lexes w ith Ru 3(CO)12. (i) (P P h 3)2P t(µ-η1:η2r,â-CHdCd
CH2)Ru (CO)Cp (1b). To a stirred solution of 1b (0.414 g,
0.434 mmol) in THF (30 mL) at -78 °C was added solid Ru3-
(CO)12 (0.320 g, 0.501 mmol). The orange suspension was
allowed to warm to room temperature over 4 h, and the
resulting red solution was stirred for an additional 12 h.
Solvent was removed in vacuo, the red residue was dissolved
in a minimum amount of CH2Cl2, and the resulting solution
was introduced onto a column of alumina (20 × 2 cm) packed
in hexane. Elution with 25% diethyl ether in hexane gave
(PPh3)(CO)Pt(µ3-η1:η2:η2-CHdCdCH2)Ru(CO)3Ru(CO)Cp (4)
CH2), 2.82 (d, J HH ) 5.1 Hz, J PtH ) 21.1 Hz, 1H of dCH2); 13
C
NMR (CDCl3) δ 213.6 (d, J PC ) 4.2 Hz, J PtC ) 50.0 Hz, FeCO’s),
203.5 (s, J PtC ) 50.0 Hz, RuCO), 191.7 (d, J PC ) 4.9 Hz, PtCO),
187.7 (d, J PC ) 4.9 Hz, dCd), 152.2 (d, J PC ) 2.7 Hz, dCPh),
84.7 (s, Cp), 13.4 (t, J CH ) 156 Hz, dCH2); 31P{1H} NMR
(CDCl3) δ 27.7 (s, J PtP ) 3074 Hz); MS (FAB), 102Ru and 195Pt
isotopes, m/z 935 (M+), 853 (M+ - 3CO). Anal. Calcd for C37H27
FeO5PPtRu: C, 47.54; H, 2.89. Found: C, 47.71; H, 2.87.
-

3182 Organometallics, Vol. 19, No. 16, 2000
Willis et al.
(ii) (P P h 3)2P t(µ-η1:η2r,â-CHdCdCH2)Ru (CO)Cp (1b). A
stirred solution of 1b (0.900 g, 0.945 mmol) in THF (100 mL)
at room temperature was treated with solid Fe2(CO)9 (0.360
g, 0.990 mmol). The original orange suspension slowly changed
to a red solution as stirring was continued for 16 h. Solvent
was removed in vacuo, and the red residue was chromato-
graphed as in the preceding reaction. Elution with 25% diethyl
ether in hexane and evaporation of the solvent afforded (PPh3)-
(CO)Pt(µ3-η1:η2:η2-CHdCdCH2)Fe(CO)3Ru(CO)Cp (6b) as a red
solid in 20% yield (0.160 g): dec pt 176 °C; IR (CH2Cl2) ν(CO)
CPh), 135.0-123.9 (m, Ph), 91.9 (s, Cp), 69.8 (s, CH2); 31P-
{1H} NMR (CDCl3) δ 24.1 (d, J PP ) 7.9 Hz, J PtP ) 4053 Hz),
22.2 (d, J PP ) 7.9 Hz, J PtP ) 2819 Hz); MS (FAB), 102Ru and
195Pt isotopes, m/z 1170 (M+ + 1), 719 (Pt(PPh3)2+). Anal. Calcd
for C54H42FeO4P2PtRu: C, 55.48; H, 3.62. Found: C, 55.77;
H, 3.89.
Rea ction s of Heter obin u clea r Meta l Allen yl Com -
p lexes w ith CO. Measured quantities (30-50 mg) of 1 or 2
were dissolved in 0.5 mL of C6D6 or CD2Cl2 in screw-cap NMR
tubes equipped with pierceable septa. Carbon monoxide or
argon was bubbled through the solution via an inlet needle
through the septum. Excess gas was vented through another
needle connected to a mineral oil bubbler.
Rea ction s of Meta l P r op a r gyl a n d Allen yl Com p lexes
w ith P t(P P h 3)2(CO)2. These reactions were carried out by
using equimolar amounts of Pt(PPh3)2(CO)2 and metal allenyl
or propargyl complex in THF solution at room temperature
(with metal allenyls) or reflux temperature (with metal pro-
pargyls). A detailed description of the reaction between Cp-
(CO)2FeCHdCdCH2 and Pt(PPh3)2(CO)2 follows.
Solid Pt(PPh3)2(CO)2 (0.250 g, 0.322 mmol) was added to a
stirred solution of Cp(CO)2FeCHdCdCH2 (0.070 g, 0.324
mmol) in THF (25 mL) at room temperature. Stirring was
continued for 2 h, at which time the reaction was complete as
ascertained by NMR spectroscopy. Removal of the solvent in
vacuo, followed by recrystallization of the residue from 2:1
hexane/THF, yielded 0.255 g (87%) of (PPh3)2Pt(µ-η1:η2R,â-CHd
CdCH2)Fe(CO)Cp (2b).
Complex 1b was obtained in an analogous manner in 90%
yield from Pt(PPh3)2(CO)2 and Cp(CO)2RuCHdCdCH2, whereas
1a resulted (92% yield) from the reaction of Pt(PPh3)2(CO)2
with Cp(CO)2RuCH2CtCPh in THF at reflux for 2 h. Complex
2a was not isolated, as the reaction of Pt(PPh3)2(CO)2 with Cp-
(CO)2FeCH2CtCPh did not proceed beyond 10% completion
(NMR spectroscopy), even after 24 h in THF at reflux tem-
perature.
Cr ysta llogr a p h ic An a lysis of (P P h 3)2P t(µ-η1:η2r,â-CHd
CdCH2)Ru (CO)Cp (1b), (P P h 3)(CO)P t(µ-η1:η2r,â-C(P h )d
CdCH2)Ru (CO)Cp (3), (P P h 3)(CO)P t(µ3-η1:η2:η2-C(P h )d
CdCH2)F e(CO)3Ru (CO)Cp (6a ), a n d (P P h 3)2P t(µ3-η1:η1:η3-
C(P h )CCH2)Ru (CO)Cp(µ2-CO)Fe(CO)2 (8). All crystals were
mounted on glass fibers and coated with varnish. Measure-
ments were done with Mo KR radiation (λ ) 0.71073 Å) on a
Nicolet R3m diffractometer with graphite monochromator.
Unit-cell parameters were obtained from the angular settings
of 25 reflections (20° e 2θ e 25°). For 6a and 8, photographic
evidence indicated 2/m Laue symmetry, and systematic ab-
sences in the data uniquely determined the monoclinic space
groups shown. For 1b and 3, the indicated Laue symmetry
was 1, and in both cases the centrosymmetric alternative was
initially assumed to be correct and later confirmed by the
refinement process. A summary of the crystal data and the
details of the intensity data collection and refinement for all
complexes are provided in Table 1.
1
2027 (s), 1997 (s), 1953 (s) cm-1; H NMR (CDCl3) δ 7.90 (d,
J PH ) 10.7 Hz, J PtH ) 47.0 Hz, 1H, dCH), 7.8-7.2 (m, 15H,
Ph), 4.64 (s, 5H, Cp), 3.54 (d, J HH ) 4.9 Hz, J PtH ) 11.4 Hz,
1H of dCH2), 2.65 (dd, J HH ) 4.9 Hz, J PH ) 1.1 Hz, J PtH
)
19.2 Hz, 1H of dCH2); 13C{1H} NMR (CDCl3) δ 214.5 (d, J PC
) 4.2 Hz, J PtC ) 48 Hz, FeCO’s), 203.7 (s, J PtC ) 9.5 Hz, RuCO),
194.9 (d, J PC ) 2.5 Hz, PtCO), 194.1 (d, J PC ) 4.9 Hz, J PtC
)
61.4 Hz, dCd), 135.5 (d, J PC ) 5.4 Hz, J PtC ) 702 Hz, dCH),
85.1 (s, Cp), 13.8 (s, J PtC ) 42.3 Hz, dCH2); 31P{1H} NMR δ
28.3 (s, J PtP ) 3092 Hz); MS (FAB), 102Ru and 195Pt isotopes,
m/z 859 (M+), 831 (M+ - CO), 803 (M+ - 2CO), 775 (M+
-
4CO), 747 (M+ - 5CO). Anal. Calcd for C31H23FeO5PPtRu: C,
43.37; H, 2.70. Found: C, 43.27; H, 2.73.
(iii) (P P h 3)2P t(µ-η1:η2r,â-CHdCdCH2)Fe(CO)Cp (2b). The
reaction was carried out similarly to the preceding one by using
0.335 g (0.369 mmol) of 2b and 0.150 g (0.412 mmol) of Fe2-
(CO)9 in 30 mL of the THF. Stirring for 21 h at room
temperature and chromatographic elution with 10% diethyl
ether in hexane gave 0.078 g (26% yield) of the red solid (PPh3)-
(CO)Pt(µ3-η1:η2:η2-CHdCdCH2)Fe(CO)3Fe(CO)Cp (7): dec pt
110 °C; IR (CH2Cl2) ν(CO) 2024 (s), 1994 (vs), 1951 (m) cm-1
;
1H NMR (CDCl3) δ 8.04 (dt, J PH ) 10 Hz, J HH ) 1.2 Hz, J PtH
) 48.1 Hz, 1H, dCH), 7.8-7.1 (m, 15H, Ph), 4.20 (s, 5H, Cp),
3.41 (dd, J HH ) 1.2, 5.0 Hz, J PtH ) 18.3 Hz, 1H of dCH2), 2.26
(dd, J HH ) 1.2, 5.0 Hz, J PtH ) 25.0 Hz, 1H of dCH2); 13C{1H}
NMR (CDCl3) δ 214.6 (s, J PtC ) 52 Hz, Fe(CO)’s), 210.3 (s, J PtC
) 13 Hz, FeCO), 194.7 (s, PtCO), 193.5 (d, J PC ) 4.0 Hz, d
Cd), 139.1 (d, J PC ) 5.0 Hz, dCH), 81.4 (s, Cp), 18.8 (s, J PtC
)
46.0 Hz, dCH2); 31P{1H} NMR (CDCl3) δ 28.5 (s, J PtP ) 3062
Hz); MS (FAB), 195Pt isotope, m/z 813 (M+), 785 (M+ - CO),
729 (M+ - 3CO), 701 (M+ - 4CO), 673 (M+ - 5CO). Anal.
Calcd for C31H23Fe2O5PPt: C, 45.78; H, 2.85. Found: C, 44.64;
H, 3.06.
R ea ct ion of (CO)3F e(µ-η3:η2-C(O)C(P h )dCdCH 2)R u -
(CO)Cp w ith P t(P P h 3)2C2H4. A solution of the RuFe title
complex (0.050 g, 0.11 mmol) in THF (10 mL) at 0 °C was
treated with solid Pt(PPh3)2C2H4 (0.078 g, 0.11 mmol), and the
resulting orange mixture was stirred for 30 min and then
allowed to warm to room temperature. After 1 h of reaction
time, a 31P{1H} NMR spectrum showed that the starting
materials had been consumed and a new complex was present
in solution. Continued stirring for an additional 5 h converted
this complex into three major products, as observed by 31P-
{1H} NMR spectroscopy. Solvent was then removed in vacuo,
and the red residue was dissolved in CH2Cl2 (1 mL) and placed
on a column of alumina (20 × 1 cm) packed in hexane. Elution
with 5% diethyl ether in hexane separated a yellow band,
which was removed from the column and evaporated to
dryness to yield orange (PPh3)(CO)Pt(µ3-η1:η2:η2-C(Ph)dCd
CH2)Fe(CO)3Ru(CO)Cp (6a ) (0.025 g, 25%). Continued elution
removed a red band, which upon evaporation of the solvent
afforded known4 (PPh3)(CO)2Fe(µ-η3:η2-C(O)C(Ph)dCdCH2)-
Ru(CO)Cp (0.015 g, 19% yield). Finally, a second red band was
eluted off; solvent removal and evaporation to dryness gave a
red solid, (PPh3)2Pt(µ3-η1:η1:η3-C(Ph)CCH2)Ru(CO)Cp(µ2-CO)-
Fe(CO)2 (8): yield 0.025 g (19%); mp 159-162 °C; IR (THF)
ν(CO) 2024 (w), 1979 (s), 1935 (vs), 1792 (m-s) cm-1; 1H NMR
(CDCl3) δ 7.36-6.85 (m, 35H, Ph), 4.74 (s, 5H, Cp), 3.05 (d, J
) 4.9 Hz, J PtH ) 44.3 Hz, 1H of CH2) (the other CH2 signal
was not observed); 13C{1H} NMR (CDCl3) δ 248.9 (s, µ-CO),
214.3 (s, FeCO’s), 205.8 (s, RuCO), 182.3 (s, CCH2), 156.4 (s,
All data sets were corrected for absorption by semiempirical
ψ-scan methods, and for decay. Structures were solved by
heavy-atom methods and subsequent difference Fourier syn-
theses. Non-hydrogen atoms were anisotropically refined, and
hydrogen atoms were treated as idealized contributions.
Phenyl rings were constrained to rigid planar hexagons with
C-C distances ) 1.395 Å.
All computations used SHELXTL (version 5.1), which also
served as the source for the neutral-atom scattering terms used
in refinement (G. Sheldrick, Nicolet (Siemens), Madison, WI).
Resu lts a n d Discu ssion
Rea ction s of Mon on u clea r Meta l η1-P r op a r gyl
a n d η1-Allen yl Com p lexes w ith P t(P P h 3)4 a n d P t-
(P P h 3)2C2H 4. The propargyl complexes Cp(CO)2-

Metal µ-Allenyl Complexes Containing Pt
Organometallics, Vol. 19, No. 16, 2000 3183
Ta ble 1. Cr ysta l Da ta , Da ta Collection , a n d Str u ctu r e Refin em en t P a r a m eter s for Com p lexes 1b, 3,
6a , a n d 8
1b
3
6a
8
formula
fw
cryst syst
space group
a (Å)
C
45H38OP2PtRu
C34H27O2PPtRu
794.71
triclinic
P1h
11.186(3)
11.992(3)
13.551(3)
100.74(2)
108.78(2)
112.03(2)
1494.4(6)
1.77
C37H27FeO5PPtRu
934.59
monoclinic
P21/n
8.433(1)
33.608(8)
12.181(2)
C54H42FeO4P2PtRu
1168.87
monoclinic
P21/n
16.724(4)
13.636(3)
20.264(4)
952.89
triclinic
P1h
11.210(2)
12.726(3)
13.984(2)
101.90(2)
101.74(2)
99.43(2)
1866.6(6)
1.70
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
99.62(2)
96.84(2)
3403.8(15)
1.82
4
4588.6(18)
1.692
4
F
calc (g cm-3
Z
)
2
2
cryst size (mm)
µ (cm-1
temp (K)
max/Tmin
2θ scan range (deg)
data collected h,k,l
no. of reflens collected
no. of indep reflens
Rmerg (%)
0.31 × 0.33 × 0.48
0.18 × 0.20 × 0.30
0.36 × 0.38 × 0.40
0.12 × 0.32 × 0.36
)
44.56
54.80
52.74
298
37.82
298
298
1.628
4-52
(14,(16,+18
7677
7357
298
2.564
4-50
(14, (15,+17
5609
5278
T
2.286
4-52
(11,+42,+16
7161
6703
2.88
1.294
4-42
(17,+14,+21
5381
4928
3.57
3.16
1.57
reflens,
6125
4390
4212
3116
F
o g 5σ(Fo)
R(F) (%)
R(wF) (%)
(∆/σ)max
No/Nv
3.49
3.65
0.011
16.2
1.020
3.85
4.11
0.19
14.4
0.90
4.63
4.69
0.103
11.5
1.198
5.11
4.86
0.25
6.44
1.140
GOF
MCH2CtCPh react with Pt(PPh3)4 in THF at reflux
over 2-9 h to afford the binuclear mixed-metal µ-alle-
nyls (PPh3)2Pt(µ-η1:η2R,â-C(Ph)dCdCH2)M(CO)Cp (M )
Ru (1a ), Fe (2a )) as yellow and orange solids in 56 and
80% yields, respectively (eq 1). The low isolated yield
analogous products, (PPh3)2Pt(µ-η1:η2R,â-CHdCdCH2)M-
(CO)Cp (M ) Ru (1b), Fe (2b)), as yellow and orange
solids, respectively (eq 2). Typically, these reactions
were commenced at -78 °C and continued with warm-
ing to room temperature until completion, and the yields
of the binuclear products ranged from 60 to 87%.
of pure 1a resulted from the difficulty of removal of the
PPh3 generated in the reaction by repeated crystalliza-
tion. Chromatographic purification could not be em-
ployed since 1a reacts with the support material.20
These problems are avoided by using Pt(PPh3)2C2H4 in
place of Pt(PPh3)4. The reaction of Cp(CO)2RuCH2Ct
CPh with Pt(PPh3)2C2H4 under comparable conditions
furnished 1a in 87% yield; however, it required a longer
time (20 h) for completion.
Previous studies in this laboratory of reactions of
metal propargyl complexes with metal carbonyls have
resulted in the preparation of binuclear and trinuclear
metal complexes of type I and II, respectively, as well
as related products with various hydrocarbyl ligands.3,4,12
The synthesis of 1a -2a by use of Pt(PPh3)4 or Pt-
(PPh3)2C2H4 represents the first successful application
of this general methodology to binuclear metal µ-η1:η2-
allenyl complexes. Furthermore, the products 1a and
2a are the first examples of mixed-metal µ-allenyl
complexes of this structural type. The formation of I and
II has been rationalized by a mechanism involving
initial ligation of the metal propargylic CtC to a
coordinatively unsaturated metal in the reacting car-
bonyl.3,4 A suitable adaptation of this mechanism, shown
The η1-allenyls Cp(CO)2MCHdCdCH2 react with Pt-
(PPh3)2C2H4 in THF or hexane under much milder
conditions than does Cp(CO)2RuCH2CtCPh to generate
(20) Shuchart, C. E.; Willis, R. R.; Haggerty, B. S.; Rheingold, A.
L.; Wojcicki, A. Inorg. Chim. Acta, in press.

3184 Organometallics, Vol. 19, No. 16, 2000
Willis et al.
Sch em e 1
1
in Scheme 1, is proposed for the reactions of Cp-
(CO)2MCH2CtCPh (M ) Ru, Fe) with Pt(PPh3)4 and
Pt(PPh3)2C2H4.
(CO)3Mo, Cp(CO)3W, (CO)5Mn), the H CH2 resonance
is observed in the region δ 3.55-2.19. The reaction of
To gain insight into the mechanism of formation of
1a , a solution of Cp(CO)2RuCH2CtCPh and Pt(PPh3)2-
C2H4 in THF-d8 at ambient temperature was monitored
by 31P{1H} NMR spectroscopy. After ca. 1 h, two new
signals were observed at δ 27.4 (d, J PP ) 37.2 Hz, J PtP
) 3350 Hz) and 26.9 (J PP ) 37.2 Hz, J PtP ) 3440 Hz). A
1H NMR spectrum of this solution showed that a doublet
has grown in at δ 2.83 (J PH ) 8.5 Hz, J PtH ) 54.4 Hz).
On prolonged storage (>18 h) or on warming the
solution, the observed intermediate (IV) substantially
converted to 1a and some 3. Attempts at isolation of
IV also resulted in the formation of 1a . Passing CO
through a solution containing IV afforded Cp(CO)2-
RuCH2CtCPh and Pt(PPh3)2(CO)2 (eq 3), which were
characterized by 1H and 31P{1H} NMR spectroscopy. No
η1-allenyl Cp(CO)2RuC(Ph)dCdCH2 was observed.
IV with CO is similar to the carbonylation of Pt(PPh3)2-
(PhCtCPh), which affords Pt(PPh3)2(CO)2 and PhCt
CPh. However, it differs from the carbonylation of 1a ,
which produces the η1-allenyl Cp(CO)2RuC(Ph)dCd
CH2, in addition to Pt(PPh3)2(CO)2 (vide infra). Thus,
it appears that IV contains an intact Cp(CO)2RuCH2Ct
CPh fragment rather than a metal allenyl group bonded
to Pt(PPh3)2.
The reactions in eq 2 represent the first examples of
synthesis of any type of binuclear or polynuclear metal
µ-allenyl complexes by treatment of metal η1-allenyls
with metal carbonyls or related precursors of coordina-
tively unsaturated reactive MLx species. The previously
reported2 reaction of Cp(CO)2RuCHdCdCH2 with Fe2-
(CO)9 afforded several mixed-metal trinuclear and tet-
ranuclear organometallics, but no metal µ-allenyls. A
reasonable mechanism for the reactions of Cp(CO)2-
MCHdCdCH2 (M ) Ru, Fe) with platinum(0) com-
plexes, which is similar to that for the corresponding
reactions of Cp(CO)2MCH2CtCPh, appears in Scheme
2.
The foregoing NMR data and the behavior of IV
toward CO suggest that this intermediate has the
structure presented in eq 3. Accordingly, the appearance
of two 31P{1H} NMR signals as doublets with similar
chemical shifts and comparable values of J PtP is con-
sistent with the presence of a Pt(PPh3)2 fragment
bonded to an unsymmetrically substituted alkyne. The
position of the 1H CH2 resonance at δ 2.83 is also
compatible with such a structure. Although we could
not find any examples of complexes containing a metal
η1-propargyl group that is η2 bonded through its CtC
to another, single metal, stable compounds are known18,21
(cf. V) where such bonding occurs to both metal atoms
of Co2(CO)6. In V (MLx ) Cp(CO)2Fe, Cp(CO)2Ru, Cp-
The proposed initial coordination of the terminal Cd
C of Cp(CO)2MCHdCdCH2 to Pt(PPh3)2 is precedented
by a spectroscopically inferred similar mode of ligation
of Cp(CO)2RuCHdCdCH2 to iron carbonyl.2 This µ-η1:
η2R,â-allenyl species would then likely isomerize to a µ-η1:
η2
counterpart, since rearrangement from µ-η1(M):
R,â
η2(Pt)-CHdCdCH2 to µ-η1(Pt):η2(M)-CHdCdCH2 is best
considered to occur from the latter. An alternative
mechanistic possibility involving isomerization of Cp-
(CO)2MCHdCdCH2 to Cp(CO)2MCH2CtCH followed by
a pathway presented in Scheme 1 seems unlikely, since
the propargyls were found to react significantly more
slowly than the η1-allenyls. No intermediates were
detected in the reaction of Cp(CO)2RuCHdCdCH2 with
Pt(PPh3)2C2H4 at ambient temperature.
(21) Wido, T. M.; Young, G. H.; Wojcicki, A.; Calligaris, M.; Nardin,
G. Organometallics 1988, 7, 452.

Metal µ-Allenyl Complexes Containing Pt
Organometallics, Vol. 19, No. 16, 2000 3185
In the 13C{1H} NMR spectra of 1 and 2 µ-allenyl
resonances were observed at δ 176.4-165.3 (dCd),
149.8-149.1 or 122.3-114.7 (dCPh or dCH, respec-
tively), and 97.2-94.3 (dCH2). These chemical shifts are
Sch em e 2
similar to those reported for Fe2(CO)6(µ-SBu-t)(µ-η1:η2
-
R,â
CHdCdCH2)9 and Fe2(CO)6(µ-PPh2)(µ-η1:η2R,â-CHdCd
CH2)10 at δ 180.0-176.6, 118.2-114.9, and 96.2-93.4,
respectively. The dCH carbon signals of 1b and 2b show
a large 1J PtC of 715-725 Hz to indicate that the µ-allenyl
is σ bonded to platinum, as well as two very different
2J PC values for trans-P,C (80.2-84.7 Hz) and cis-P,C
1
(e4.5 Hz). The magnitude of the coupling constant J CH
(160 Hz) in the 13C NMR spectrum of 1b is consistent
with sp2 hybridization at this dCH carbon. The dCH2
resonances reveal carbon-13 coupling to one phosphorus
(3J PC ) 2.3-3.5 Hz) and to platinum-195 (2J PtC ) 32-
1
42 Hz). As for the dCH above, J CH values of 160 Hz
for both 1a and 1b indicate sp2 hybridization at the d
CH2 carbon. The relative downfield position at δ 97.2-
94.3 of the dCH2 13C resonance of 1 and 2 is consistent
with the presence of uncoordinated CâdCγ and points
to a µ-η1:η2R,â-allenyl structure. For comparison, M2-
(CO)6(µ-PPh2)(µ-η1:η2â,γ-C(Ph)dCdCH2) (M2 ) Ru2 or
Os2) display 13C dCH2 signals much farther upfield, at
δ 1.0 (Ru2) and -3.3 (Os2).8b
Ch a r a cter iza tion of Heter obin u clea r Meta l µ-η1:
η2r,â-Allen yl Com p lexes. The new heterobinuclear
metal complexes 1a ,b and 2a ,b were characterized by
IR and NMR (1H, 13C{1H}, and 31P{1H}) spectroscopy,
FAB mass spectrometry, and chemical analysis. All four
complexes yielded excellent C and H analysis and
showed parent ion peaks in their mass spectra.
The PPh3 ligands are, as expected, inequivalent in the
31P{1H} NMR spectrum, giving rise to two signals in
2
the range δ 30.9-21.5 with a J PP ) 1.0-4.3 Hz and
characteristic 1J PtP values of 2766-2925 and 3415-3689
The IR spectrum of each complex shows a single ν-
(CO) absorption at 1912-1896 cm-1; this absorption
occurs at a lower frequency (13-16 cm-1) for the PtFe
complexes than for their PtRu counterparts. The pres-
ence of a carbonyl ligand is also evident in the 13C{1H}
NMR spectra: the PtFe complexes show a signal at δ
220.4-220.2, whereas the PtRu complexes resonate at
δ 206.9-206.6, all with platinum-195 satellites.
1
Hz. The signal with the smaller J PtP is assigned to the
phosphorus trans to the allenyl CR which belongs to the
more labile phosphine.22,23 This feature will be ad-
dressed again in the context of structure and reactivity
of 1 and 2.
The characterization of 3, prepared by treatment of
1a with CO or with Fe2(CO)9 (vide infra), is considered
together with that of 1 and 2 because of the structural
similarity of these complexes.24 The IR spectrum of 3
The 1H and 13C{1H} NMR spectra of 1 and 2 are
entirely consistent with the presence of a µ-η1:η2
-
R,â
shows two ν(CO) absorptions at 2018 and 1947 cm-1
,
allenyl ligand that is η1 bonded to Pt and η2 bonded to
and the presence of two carbonyls is also evident in the
1
Ru or Fe. Accordingly, the methine H resonance of 1b
13C{1H} NMR spectrum, which reveals resonances at δ
and 2b occurs at δ 6.61 (2J PtH ) 33.0 Hz) and 7.03 (2J PtH
) 36.8 Hz), respectively. In the homobinuclear metal
complexes Fe2(CO)6(µ-SBu-t)(µ-η1:η2R,â-CHdCdCH2)9 and
Fe2(CO)6(µ-PPh2)(µ-η1:η2R,â-CHdCdCH2),10 the respec-
tive dCH signals are observed at δ 8.7 and 7.39. The
dCH2 protons of 1 and 2 are inequivalent (δ 5.44-5.26
and 4.89-4.66) and show geminal coupling (2J HH ) 1.0-
2
204.2 (RuCO) and 193.2 (PtCO, J PC ) 5.0 Hz). The
µ-allenyl ligand is η1:η2 bonded, as reflected by the
R,â
slightly broadened (probably owing to unresolved gemi-
1
nal coupling) H NMR signals of the CH2 group at δ
5.60 and 5.02 with the accompanying platinum-195
satellites (4J PtH ) 17.7 and 14.4 Hz, respectively) and
by the 13C{1H} NMR signals at δ 163.3 (dCd), 148.2
(dCPh), and 98.4 (dCH2), all very similar to those for
1a and 2a . There is only a single 31P{1H} resonance at
2.5 Hz) as well as coupling to platinum-195 (4J PtH
)
10.0-19.7 Hz). In contrast, the methylene protons of the
homobinuclear Fe2(CO)6(µ-SBu-t)(µ-η1:η2R,â-CHdCdCH2)9
and Fe2(CO)6(µ-PPh2)(µ-η1:η2R,â-CHdCdCH2)10 are
equivalent at ambient temperature owing to fluxional
behavior. A “windshield-wiper” type motion of the
allenyl ligand was proposed to account for this fluxion-
ality. Such an interchange pathway is entirely reason-
able for homobinuclear complexes with identical ligand
environments (except for the µ-η1:η2R,â-allenyl) at the
two metals, since it leads to no net change in structure.
However, for 1 and 2, µ-η1(Pt):η2(Ru or Fe)-allenyl and
µ-η1(Ru or Fe):η2(Pt)-allenyl attachments would be
involved, and therefore an analogous mechanism may
not be favorable. We find that complex 1a does not
exhibit fluxional behavior even at 100 °C in toluene
solution.
1
δ 24.4, with a J PtP ) 3277 Hz. The chemical composi-
tion of 3 was confirmed by elemental analysis and by
the appearance of the parent ion peak in the FAB mass
spectrum.
Single-crystal X-ray diffraction studies of 1b and 3
were undertaken to provide precise structural details
and possibly help rationalize different chemical reactiv-
ity of the two complexes (vide infra). Yellow crystals of
(22) Pidcock, A. In Catalytic Aspects of Metal Phosphine Complexes;
Alyea, E. C., Meek, D. W., Eds.; American Chemical Society: Wash-
ington, D.C., 1982; p 1.
(23) Willis, R. R.; Calligaris, M.; Faleschini, P.; Gallucci, J . C.;
Wojcicki, A. J . Organomet. Chem. 2000, 593/ 594, 465.
(24) Complex 3 was incorrectly reported as (PPh3)Pt(µ-η3:η2-C(Ph)d
CdCH2)Ru(CO)Cp in review articles.1a,c

3186 Organometallics, Vol. 19, No. 16, 2000
Willis et al.
Ta ble 3. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for 3
Pt-Ru
2.668(1)
2.293(2)
1.882(10)
2.025(9)
2.162(9)
2.107(8)
Ru-C(2)
1.844(12)
1.402(9)
1.313(9)
1.507(11)
1.140(12)
1.155(15)
Pt-P
C(10)-C(9)
C(9)-C(8)
C(10)-C(16)
C(1)-O(1)
C(2)-O(2)
Pt-C(1)
Pt-C(10)
Ru-C(10)
Ru-C(9)
Ru-Pt-P
153.4(1)
108.3(3)
97.8(3)
52.7(3)
101.7(3)
160.1(4)
73.7(3)
100.8(4)
80.5(4)
77.8(3)
Pt-Ru-C(10)
48.2(2)
68.7(5)
114.3(7)
138.5(9)
73.0(4)
148.5(10)
121.0(8)
175.7(8)
176.1(10)
Ru-Pt-C(1)
P-Pt-C(1)
Ru-C(10)-C(9)
Pt-C(10)-C(9)
Ru-C(9)-C(8)
Ru-C(9)-C(10)
C(10)-C(9)-C(8)
C(9)-C(10)-C(16)
Pt-C(1)-O(1)
Ru-C(2)-O(2)
Ru-Pt-C(10)
P-Pt-C(10)
C(1)-Pt-C(10)
Pt-Ru-C(9)
C(10)-Ru-C(2)
C(9)-Ru-C(2)
Pt-Ru-C(2)
C(1)HdC(2)dC(3)H2 in 1b and C(10)(Ph)dC(9)dC(8)-
H2 in 3 are characterized by the C(1)-C(2) and C(10)-
C(9) distances of 1.383(9) and 1.402(9) Å, respectively,
which are typical of the CdC bonds elongated by
coordination to metal.1 In contrast, the bond lengths
C(2)-C(3) and C(9)-C(8), 1.308(10) and 1.313(9) Å,
respectively, represent normal distances of free CdC.
For comparison, in the homobinuclear metal complexes
Fe2(CO)6(µ-SBu-t)(µ-η1:η2R,â-CHdCdCH2)9 and Fe2(CO)6-
(µ-PPh2)(µ-η1:η2R,â-CHdCdCH2)10 the distances CR-Câ
are 1.365(3) and 1.363(9) Å, whereas the distances Câ-
Cγ are 1.317(3) and 1.335(9) Å, respectively. The allenyl
bond angles C(1)-C(2)-C(3) in 1b and C(10)-C(9)-C(8)
in 3 measure, in the indicated order, 147.3(7)° and
148.5(10)°. They are somewhat less obtuse than the
bond angles 153.1(2)° and 156.7(7)° reported respec-
tively for Fe2(CO)6(µ-SBu-t)(µ-η1:η2R,â-CHdCdCH2)9 and
Fe2(CO)6(µ-PPh2)(µ-η1:η2R,â-CHdCdCH2).10 However, the
bond angles in all of the foregoing and other crystallo-
graphically characterized µ-η1:η2R,â-allenyl metal
complexes8a,23,30 are considerably smaller than the
corresponding bond angles in the µ-η1:η2â,γ-allenyl
complexes Ru2(CO)6(µ-PPh2)(µ-η1:η2â,γ-C(Ph)dCdCH2)
(172.3(3)°)8b and its Os2 analogue (170.6(11)°).1c
F igu r e 1. ORTEP diagram of 1b. Only the ipso carbon
atoms of the PPh3 groups are shown, and the hydrogen
atoms are omitted.
F igu r e 2. ORTEP diagram of 3. Phenyl hydrogen atoms
have been omitted.
Ta ble 2. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for 1b
Pt-Ru
2.718(1)
2.302(2)
2.255(2)
2.015(6)
2.116(6)
Ru-C(2)
Ru-C(4)
C(1)-C(2)
C(2)-C(3)
C(4)-O(4)
2.098(7)
1.838(6)
1.383(9)
1.308(10)
1.147(7)
Pt-P(1)
Pt-P(2)
Pt-C(1)
Ru-C(1)
The two Pt-P bond distances in 1b are unequal, with
Pt-P(1) ) 2.302(2) and Pt-P(2) ) 2.255(2) Å. A slightly
longer Pt-P bond distance for the phosphorus ap-
proximately trans to the bridging hydrocarbyl CR (P(1)-
Pt-C(1) ) 156.8(2)°) compared to that approximately
trans to Ru (Ru-Pt-P(2) ) 142.9(1)°) has been also
noted in other µ-allenyl and related complexes contain-
ing a RuPt(PPh3)2 fragment.23,31 Significantly, it is the
PPh3 trans to Ru (Ru-Pt-P ) 153.4(1)°) that remains
in the product complex 3 after carbonylation of 1a . The
other PPh3 ligand of 1a , trans to the allenyl CR,
undergoes substitution by CO.
Ru-Pt-P(1)
P(1)-Pt-P(2)
Ru-Pt-C(1)
P(2)-Pt-C(1)
P(1)-Pt-C(1)
Ru-Pt-P(2)
Pt-Ru-C(2)
C(1)-Ru-C(4)
C(2)-Ru-C(4)
109.2(1)
107.4(1)
50.5(2)
94.6(2)
156.8(2)
142.9(1)
76.3(2)
98.2(3)
84.1(3)
Pt-Ru-C(4)
75.1(2)
47.3(2)
70.2(4)
123.9(4)
141.1(6)
71.5(4)
147.3(7)
176.3(7)
Pt-Ru-C(1)
Ru-C(1)-C(2)
Pt-C(1)-C(2)
Ru-C(2)-C(3)
Ru-C(2)-C(1)
C(1)-C(2)-C(3)
Ru-C(4)-O(4)
the two complexes were grown from dichloromethane/
hexane at -5 °C (1b) and room temperature (3). The
respective molecular structures of 1b and 3 are shown
in Figures 1 and 2, whereas selected bond distances and
angles are given in Tables 2 and 3. The two structures
are remarkably similar. Both contain a µ-allenyl ligand
that is η1 bonded to Pt and η2 attached, through the CRd
Câ bond, to Ru. The Pt-Ru bond distances of 2.718(1)
Å in 1b and 2.668(1) Å in 3 fall in the range of Pt-Ru
bond lengths reported for a number of trinuclear and
tetranuclear complexes.25-29 The µ-allenyl ligands
Our final comments in this section concern η1:η2R,â vs
η1:η2â,γ bonding for binuclear metal µ-allenyl complexes.
(26) Bruce, M. I.; Matisons, J . G.; Skelton, B. W.; White, A. H. Aust.
J . Chem. 1982, 35, 687.
(27) Ewing, P.; Farrugia, L. J . Organometallics 1989, 8, 1246.
(28) Adams, R. D.; Wu, W. Organometallics 1993, 12, 1248.
(29) Farrugia, L. J . In Comprehensive Organometallic Chemistry II;
Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: Oxford,
U.K., 1995; Vol. 10, Chapter 4.
(30) Blenkiron, P.; Corrigan, J . F.; Taylor, N. J .; Carty, A. J .;
Doherty, S.; Elsegood, M. R. J .; Clegg, W. Organometallics 1997, 16,
297.
(25) Modinos, A.; Woodward, P. J . Chem. Soc., Dalton Trans. 1975,
1534.
(31) Willis, R. R.; Calligaris, M.; Faleschini, P.; Wojcicki, A. J .
Cluster Sci. 2000, 11, 233.

Metal µ-Allenyl Complexes Containing Pt
Organometallics, Vol. 19, No. 16, 2000 3187
With the exception of M2(CO)6(µ-PPh2)(µ-η1:η2â,γ-C(Ph)d
CdCH2) (M2 ) Ru2 or Os2),8b all of the structurally
1,10,23,30
characterized compounds are of the type µ-η1:η2
.
R,â
It has been suggested10 that this structural preference
for Fe2(CO)6(µ-PPh2)(µ-η1:η2R,â-CHdCdCH2) may result
from the relatively short M-M bond distance when M
is a first-row transition metal. However, the present and
another recent study23 show that even the heavier
metals Pt and Ru, with longer M-M bond distances,
invariably afford binuclear µ-η1:η2R,â-allenyl complexes
and do so irrespective of whether ambient or high
temperatures are employed in their synthesis. Further-
more, the preparative methods used in this study would
not be expected to result in a preference for either the
internal or the terminal allenyl CdC bond coordination
to metal in the product. Therefore, it appears that other
factors must be involved in dictating the preference for
µ-η1:η2 bonding, especially for the second- and third-
R,â
row transition metals.
One of those factors may be metal-to-(η2-allenyl)
π-bonding, which is expected to have an effect on M-M
bond distance. Metal-to-(CâdCγ) π-interaction will lead
to CR-Câ-Cγ bending, which in turn will enhance
separation between the metal atoms. For the heavier
metals, which engage more extensively in π-bonding
than their lighter counterparts, M-to-M separation may
thus become too large for a bonding interaction to occur.
As a result, the metal will prefer interaction with CRd
Câ, which positions it within bonding distance of the
other metal. Interestingly, in the complex Ru2(CO)6(µ-
PPh2)(µ-η1:η2â,γ-C(Ph)dCdCH2), the bond distance Ru-
Ru ) 2.860(1) Å and the bond angle CR-Câ-Cγ
)
172.3(3)°;8b this is to be compared with Ru-Ru )
2.7863(8) Å (av) and CR-Câ-Cγ ) 143.7(4)° (av) in Ru2-
(CO)6(µ-PPh2)(µ-η1:η2R,â-C(Ph)dCdCPh2).8a The near
linearity of the CR-Câ-Cγ fragment in the former may
result as a compromise between strength of the Ru-to-
(CâdCγ) π-interaction and a Ru-Ru bond distance
needed to effect µ-η1:η2â,γ-allenyl ligation.
(CO)4PPh3 may be ascribed to fragmentation of Ru3-
(CO)12 and Fe2(CO)9 to mononuclear carbonyl species
and reaction of the latter with the PPh3 released by the
Pt(PPh3)2 fragment of 1 and 2 during its conversion to
the Pt(CO)PPh3 in 3-7. This fragmentation to generate
labile metal carbonyls also accounts for the ready
availability of free CO required for the substitution at
platinum.
The surprising aspect of the formation of 4-7 accord-
ing to eqs 4 and 5 concerns connectivity of the two Cd
C bonds of the µ-allenyl to M′(CO)3 and M(CO)Cp. It
had been expected that the free CâdCγ bond of 1 and 2
would coordinate to the incipient M′(CO)3, while the
CRdCâ bond would remain attached to M(CO)Cp. The
observed opposite coordination selectivity suggests that
the reactive site in 1 and 2 is not CâdCγ. Instead, the
simplest mechanistic scenario would appear to entail
insertion of M′(CO)3 into the Pt-M(CO)Cp bond and
displacement of M(CO)Cp from CRdCâ to CâdCγ. The
reason for this preference is not obvious, since the
alternative Pt-M-M′ bond sequence would also lead
to a stable electronic arrangement at each metal. The
substitution of CO for PPh3 at Pt(PPh3)2 probably occurs
in the final stages of the reaction, as evidenced by a
virtual lack of reactivity toward Fe2(CO)9 of the Pt(CO)-
PPh3-containing complex 3.
Rea ction s of Heter obin u clea r Meta l µ-η1:η2
-
r,â
Allen yl Com p lexes w ith Ru th en iu m a n d Ir on Ca r -
bon yls. The reactions of 1 and 2 with an excess of
Ru3(CO)12 (eq 4) or Fe2(CO)9 (eq 5) were generally
conducted in THF at room temperature. The orange
solutions of the reactants gradually darkened to red, and
1
complete reaction was observed within 16-36 h by H
and 31P{1H} NMR spectroscopy. The reaction of 2b with
Ru3(CO)12 was also carried out in hexane at reflux and
reached completion in 1 h. All of the products were
isolated after column chromatography on alumina of the
crude reaction mixtures.
The principal products of these reactions are the
heterotrimetallic µ3-η1:η2:η2-allenyl complexes (PPh3)-
(CO)Pt(µ3-η1:η2:η2-C(R)dCdCH2)M′(CO)3M(CO)Cp (M′
) M ) Ru, R ) H (4); M′ ) Ru, M ) Fe, R ) H (5); M′
) Fe, M ) Ru, R ) Ph (6a ); M′ ) Fe, M ) Ru, R ) H
(6b); M′ ) M ) Fe, R ) H (7)), which were isolated as
red or orange (6b) solids in 17-34% yield. The reaction
of 1a with Fe2(CO)9 afforded, in addition to 6a , the
heterobimetallic µ-η1:η2R,â-allenyl complex 3 in 12%
yield. Another major side product encountered in the
synthesis of 4-7 was M′(CO)4PPh3 (M′ ) Ru or Fe).
These secondary products were readily separated from
4-7 by column chromatography. The formation of M′-
Ch a r a cter iza tion of Heter otr in u clea r Meta l µ3-
η1:η2:η2-Allen yl Com p lexes. The chemical composition
of complexes 4-7 was established by elemental analysis

3188 Organometallics, Vol. 19, No. 16, 2000
Willis et al.
and FAB mass spectrometry, which showed the parent
ions and fragments resulting from loss of CO. Consider-
able information concerning the structure of 4-7 was
obtained from the IR and 1H, 13C{1H}, and 31P{1H}
NMR spectra, although these data did not unequivocally
resolve the questions of µ-allenyl-metal and metal-
metal connectivity. For that reason, an X-ray analysis
of 6a was undertaken. The other heterotrinuclear metal
µ-allenyls are assigned structures similar to that of 6a
on the basis of their spectroscopic similarities. Salient
spectroscopic properties will be examined first.
The IR spectra of 4-7 in the ν(CO) region exhibit
three or four bands at 2038-1951 cm-1 due to terminal
carbonyl ligands. The presence of CO at each of the
three metal centers is unambiguously indicated by the
13C{1H} NMR spectra, which show signals of the FeCO
at δ 216.1-210.3, RuCO at δ 208.0-200.7, and PtCO
at δ 199.9-191.7. Separate resonances were observed
for the CO’s bonded to the two Ru and the two Fe atoms
in 4 and 7, respectively, with those of the M(CO)3
carbonyls in all of 4-7 being broadened by fluxionality.
No platinum-195 satellites could be detected for the
PtCO signals owing to the low intensity of these
resonances.
F igu r e 3. ORTEP diagram of 6a . The hydrogen atoms
have been omitted.
Ta ble 4. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for 6a
Pt-Fe
2.528(2)
2.761(2)
2.291(3)
1.874(12)
2.022(9)
1.752(12)
1.792(12)
1.767(12)
Fe-C(12)
Fe-C(13)
Ru-C(2)
Ru-C(11)
Ru-C(12)
C(11)-C(12)
C(12)-C(13)
1.981(10)
2.116(10)
1.832(13)
2.214(9)
2.116(9)
1.431(13)
1.362(13)
Ru-Fe
Pt-P
Pt-C(1)
Pt-C(13)
Fe-C(3)
Fe-C(4)
Fe-C(5)
The positions of the resonances of the allenyl hydro-
gen and carbon atoms reflect coordination to metal of
both CdC bonds. Accordingly, the dCH2 protons give
rise to two signals in the range δ 3.86-2.26 with the
2
geminal coupling constant J HH ) 4.0-5.0 Hz and
Pt-Fe-Ru
84.1(1)
158.4(1)
158.0(5)
104.4(4)
54.0(3)
Pt-C(13)-C(12)
Pt-C(13)-C(26)
Ru-C(12)-C(13)
C(13)-C(12)-C(11)
Pt-C(1)-O(1)
Ru-C(2)-O(2)
Fe-C(5)-O(5)
114.2(6)
124.5(6)
129.1(7)
149.7(9)
175.5(12)
175.0(10)
173.5(9)
platinum-195 satellites (4J PtH e 25.0 Hz). The positions
of these signals are considerably upfield from those of
the binuclear µ-η1:η2R,â-allenyl precursors (δ 5.44-5.26
and 4.89-4.66). Such an upfield shift is typical for d
CH2 protons upon coordination of the CdCH2 to metal.32
The methine proton in 4, 5, 6b, and 7 resonates at δ
8.04-7.21 and shows coupling to 195Pt (47-50 Hz), 31P
(10-11 Hz), and, in some cases, CH2 protons (e1.1 Hz).
The allenyl carbon atoms of 4-7 display 13C{1H} NMR
signals at δ 196.9-187.7 (dCd), 167.4-135.5 (dCH or
dCPh), and 44.9-13.4 (dCH2), with irregularly ob-
Fe-Pt-P
C(1)-Pt-C(13)
Fe-Pt-C(1)
Fe-Pt-C(13)
P-Pt-C(1)
P-Pt-C(13)
97.3(4)
104.4(3)
Ru bond angle is 84.1(1)°, nearly a right angle, and large
enough so as not to allow for a bonding interaction
between Pt and Ru (Pt-Ru separation ) 3.55 Å, ca.
0.7-0.9 Å longer than a Pt-Ru single bond29). The Pt-
Fe bond length of 2.528(2) Å is somewhat shorter than
that found in (CO)3Fe(µ-CO)(µ-dppm)PtBr2 (2.6474(4)
Å, dppm ) bis(diphenylphosphino)methane),33 (CO)3-
(SiPh3)Fe(µ-PPh2)Pt(CO)PPh3 (2.620(1) Å),34 and a num-
ber of other platinum-iron complexes.29 The Ru-Fe
single bond distance of 2.761(2) Å falls in the range of
Ru-Fe distances observed in binuclear and trinuclear
ruthenium-iron µ-allenyl and related complexes (2.62-
2.79 Å).2,4 The µ-allenyl ligand is η1 bonded to Pt (Pt-
C(13) ) 2.022(9) Å) and η2 bonded through each the
internal C(12)dC(13) and the terminal C(11)dC(12)
double bond to Fe (Fe-C(13) ) 2.116(10), Fe-C(12) )
1.981(10) Å) and Ru (Ru-C(12) ) 2.116(9), Ru-C(11)
) 2.214(9) Å), respectively. These distances are compa-
rable to the M-C bond distances associated with
µ-allenyl groups in related compounds.2,4,8,10,30 Both
C(12)dC(13) (1.362(13) Å) and C(11)dC(12) (1.431(13)
Å) are elongated by coordination to metal from free Cd
C bonds in metal η1-allenyl complexes.35-37 Carbon-
served coupling to 31P (J PC e 5.4 Hz) and 195Pt (1J PtC
≈
2
3
700 Hz, J PtC ≈ 60 Hz, J PtC ) 46 Hz). As noted for the
dCH2 protons, the dCH2 carbon resonance occurs at a
considerably higher field for 4-7 than for the precursor
1 or 2 to suggest coordination of the CâdCγ to metal. It
1
is also noteworthy that the J CH of 156 Hz for the d
CH2 of 6a is slightly less than that of the parent complex
1
1a or of 1b (both J CH ) 160 Hz) to indicate a lower s
character of the carbon bond to hydrogen upon ligation.
Furthermore, the chemical shifts of the allenyl carbon
atoms in 4-7 are very similar to those reported for the
structurally analogous triangular metal µ3-η1:η2:η2-
allenyl complexes III.1b,c
Orange crystals of 6a for an X-ray diffraction study
were obtained from dichloromethane/hexane. The mo-
lecular structure together with the atom-numbering
scheme is shown in Figure 3, whereas selected bond
distances and angles are given in Table 4. Molecules of
6a are comprised of the Pt(CO)PPh3, Fe(CO)3, and Ru-
(CO)Cp fragments that are Pt-Fe-Ru bonded in an
open trimetallic array. The metal-metal bonds are
supported by a µ-η1:η2:η2-allenyl ligand. The Pt-Fe-
(33) J acobsen, G. B.; Shaw, B. L.; Thornton-Pett, M. J . Chem. Soc.,
Dalton Trans. 1987, 3079.
(34) Reinhard, G.; Knorr, M.; Braunstein, P.; Schubert, U.; Khan,
S.; Strouse, C. E.; Kaesz, H. D.; Zinn, A. Chem. Ber. 1993, 126, 17.
(35) Huang, T.-M.; Hsu, R.-H.; Yang, C.-S.; Chen, J .-T.; Lee, G.-H.;
Wang, Y. Organometallics 1994, 13, 3657.
(32) Pruchnik, F. P. Organometallic Chemistry of the Transition
Elements; Plenum: New York, 1990; Chapter 6.
(36) Wouters, J . M. A.; Klein, R. A.; Elsevier: C. J .; Ha¨ming, L.;
Stam, C. H. Organometallics 1994, 13, 4586.

Metal µ-Allenyl Complexes Containing Pt
Organometallics, Vol. 19, No. 16, 2000 3189
carbon bond lengthening of a similar magnitude has
been noted for triangular metal µ-η1:η2:η2-allenyl com-
plexes, with CâdCγ generally being longer than CRd
Câ.1b,c The angle C(13)-C(12)-C(11) of 6a (149.7(9)°)
is in the range observed for closed trinuclear metal
µ-allenyls II (127-152°).1b,c
Complexes 4-7 are representative of 48-electron open
trinuclear metal clusters.38 Such clusters are known for
PtM2 (e.g., M ) Mn, Fe, Co); however, they adopt linear
or close to linear structure, with Pt bonded to both M
atoms.38-40 Triangular, Pt-containing clusters also have
been reported.29,38 We attempted to convert 6a to a
closed trimetallic cluster by thermolysis and photolysis,
however without much success. No reaction was ob-
served when 6a in THF was heated at 60 °C for 24 h.
Photolysis with 254 nm lamps resulted in ca. 50%
consumption of 6a accompanied by loss of CO to form a
product that showed two CH2 proton resonances at δ
3.75 (J HH ) 3.0, J PtH ) 9.0 Hz) and 3.61 (J HH ) 3.0,
J PtH ) 8.0 Hz) and a 31P{1H} NMR signal at δ 26.2 (1J PtP
) 3398 Hz). However, this product could not be isolated
pure because of instability in solution and toward
column chromatography.
Complex 8 was characterized by elemental analysis,
FAB mass spectrometry, and IR and NMR spectroscopy.
Its structure was determined by an X-ray diffraction
analysis. The 1H NMR spectrum shows a doublet
resonance at δ 3.05 (2J HH ) 4.9, 3J PtH ) 44.3 Hz), which
is assigned to one of the inequivalent protons of CH2.
The signal of the second proton could not be located. In
the 13C{1H} NMR spectrum, resonances are observed
of a bridging CO (δ 248.9),41 FeCO’s (δ 214.3), and a
RuCO (δ 205.8). The signals at δ 182.3, 156.4, and 69.8
are assigned to Câ, CR, and Cγ, respectively, of a new C3
hydrocarbyl ligand.23,31 However, the nature of this
ligand and its connectivity to metals are not apparent
from these data. No platinum-195 satellites could be
observed in the spectrum owing to the limited solubility
of 8. The two 31P{1H} resonances at δ 24.1 (1J PtP ) 4053
Hz) and 22.2 (1J PtP ) 2819 Hz) point, as in the case of
the reaction intermediate, to the presence of a hydro-
carbyl carbon and Ru or Fe at the Pt center.
Because the foregoing data left an incomplete struc-
tural picture of 8, an X-ray diffraction study was carried
out on a crystal obtained from chloroform/hexane at -23
°C. The molecular structure is shown in Figure 4, and
selected bond distances and angles are furnished in
Table 5. Molecules of 8 may be described as open, Pt-
Fe-Ru (angle ) 125.9(1)°) bonded clusters containing
an η3-allyl ligand (C(5)C(6)C(7)) attached to iron. The
Pt(PPh3)2 group is connected essentially symmetrically
to the central carbon C(6) (Pt-C(6)-C(5) ) 114.6(11)°,
Pt-C(6)-C(7) ) 111.4(11)°), whereas the Ru(CO)Cp
fragment is an anti substituent at the terminal CPh
(C(7)). The C-C bond distances of the η3-allyl ligand
are unequal (C(5)-C(6) ) 1.341(23) Å, C(6)-C(7) )
1.433(19) Å), and the angle C(5)-C(6)-C(7) is normal
(120.9(13)°). The two Pt-P bond lengths are different,
with Pt-P(1) (2.299(4) Å) > Pt-P(2) (2.258(4) Å), as
expected for phosphines trans to a hydrocarbyl carbon
and a metal, respectively.22,23 The Pt-Fe bond distance
of 2.696(2) Å is normal (cf. discussion of the structure
of 6a ). The Ru-Fe bond length (2.639(3) Å) is also
unexceptional and may be compared with that of 2.742-
(2) Å in VI.4 The former bond is supported by an
unsymmetrically bridging carbonyl C(3)O(3) (Fe-C(3)
) 1.918(16) Å, Ru-C(3) ) 2.125(17) Å; Fe-C(3)-O(3)
) 147.7(14)°, Ru-C(3)-O(3) ) 131.0(13)°).
Rea ction of (CO)3F e(µ-η3:η2-C(O)C(P h )dCdCH2)-
Ru (CO)Cp (VI) w ith P t(P P h 3)2C2H4 a n d Ch a r a c-
t er iza t ion of a H et er ot r in u clea r Met a l P r od u ct ,
(P P h 3)2P t(µ3-η1:η1:η3-C(P h )CCH2)Ru (CO)Cp (µ2-CO-
)F e(CO)2 (8). Since the reactions of 1 and 2 with iron
and ruthenium carbonyls lead to insertion of the Fe-
(CO)3 and Ru(CO)3 fragments into the Pt-Ru and Pt-
Fe bonds, it was of interest to ascertain whether
reaction of a similar binuclear RuFe complex with Pt-
(PPh3)2C2H4 would result in the formation of a Ru-Pt-
Fe bonded product. The µ-allenylcarbonyl (CO)3Fe(µ-η3:
η2-C(O)C(Ph)dCdCH2)Ru(CO)Cp (VI) was selected for
this experiment, as analogous binuclear RuFe µ-allenyls
are not known. Although both CdC bonds are ligated
to metal in VI, this feature was not expected to impede
reactivity. The reactions of 1 and 2 with Fe3(CO)12 and
Ru3(CO)12 suggest that a free CdC bond of µ-allenyl
does not initiate the formation of trimetallic products.
Stirring a THF solution of equimolar amounts of VI
and Pt(PPh3)2C2H4 first at 0 °C and then at room
temperature afforded a mixture of three products (eq
6), which were separated by column chromatography
and isolated in the indicated yields: orange 6a (25%),
known4 red-orange (PPh3)(CO)2Fe(µ-η3:η2-C(O)C(Ph)d
CdCH2)Ru(CO)Cp (19%), and red (PPh3)2Pt(µ3-η1:η1:η3-
C(Ph)CCH2)Ru(CO)Cp(µ2-CO)Fe(CO)2 (8) (19%). Moni-
toring the reaction solution by 31P{1H} NMR spectroscopy
resulted in the detection of an intermediate with signals
at δ 25.4 (1J PtP ) 3877 Hz) and 22.3 (1J PtP ) 2866 Hz).
1
These values of J PtP would be consistent with the
presence of Ru or Fe and a hydrocarbyl group in the
positions trans to the respective PPh3 ligands at plati-
num.22,23 The intermediate decomposed to the afore-
mentioned three products.
(37) Blosser, P. W.; Calligaris, M.; Faleschini, P.; Wojcicki, A.
Manuscript in preparation.
(38) Mingos, D. M. P.; May, A. S. In The Chemistry of Metal Cluster
Complexes; Shriver, D. F., Kaesz, H. D., Adams, R. D., Eds.; VCH
Publishers: New York, 1990; Chapter 2.
(39) Moras, D.; Dehand, J .; Weiss, R. C. R. Acad. Sci., Ser. C 1968,
267, 1471.
(40) Braunstein, P.; Predieri, G.; Lahoz, F. J .; Tiripicchio, A. J .
Organomet. Chem. 1985, 288, C13.
(41) Elschenbroich, Ch.; Salzer, A. Organometallics, 2nd ed.; VCR
Publishers: New York, 1992; p 298.

3190 Organometallics, Vol. 19, No. 16, 2000
Willis et al.
reactions of 1 and 2. We find that 1b and 2b readily
react according to eq 7 when CO is passed through their
solutions in CD2Cl2 at room temperature.
In ca. 3 h, 31P{1H} NMR spectra showed complete
disappearance of 1b and 2b and formation of Pt(PPh3)2-
F igu r e 4. ORTEP diagram of 8. Only the ipso carbon
atoms of the PPh3 groups are shown, and the hydrogen
atoms are omitted.
1
(CO)2,17 while H NMR spectra demonstrated the pres-
ence of Cp(CO)2MCHdCdCH2 (M ) Ru, Fe). Carbon
monoxide was then replaced with Ar, and after 2 h
complete regeneration of 1b and 2b was noted. This
cycle can be repeated at least two more times without
observation of any significant decomposition.
Reactions of 1a and 2a proceed much less readily than
those of 1b and 2b. Thus, bubbling CO through a
solution of 2a in CD2Cl2 at room temperature afforded
only ca. 50% conversion to Cp(CO)2FeCH2CtCPh and
Pt(PPh3)2(CO)2 after 18 h (eq 8). Replacement of CO
Ta ble 5. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for 8
Pt-Fe
2.696(2)
2.639(3)
2.299(4)
2.258(4)
2.062(15)
1.824(18)
1.748(18)
1.918(16)
Fe-C(5)
Fe-C(6)
Fe-C(7)
Ru-C(3)
Ru-C(4)
Ru-C(7)
C(5)-C(6)
C(6)-C(7)
2.141(16)
1.965(16)
2.037(14)
2.125(17)
1.849(17)
2.102(13)
1.341(23)
1.433(19)
Ru-Fe
Pt-P(1)
Pt-P(2)
Pt-C(6)
Fe-C(1)
Fe-C(2)
Fe-C(3)
Pt-Fe-Ru
125.9(1)
138.6(1)
161.9(4)
115.8(1)
46.4(4)
101.9(1)
96.0(4)
103.5(5)
93.1(7)
93.4(6)
70.5(6)
Pt-C(6)-C(5)
Pt-C(6)-C(7)
Ru-C(7)-C(6)
Ru-C(3)-O(3)
Ru-C(4)-O(4)
Fe-C(1)-O(1)
Fe-C(2)-O(2)
Fe-C(3)-O(3)
C(5)-C(6)-C(7)
C(6)-C(7)-C(18)
114.6(11)
111.4(11)
122.0(10)
131.0(13)
168.1(14)
174.0(15)
178.3(18)
147.7(14)
120.9(13)
122.4(12)
Fe-Pt-P(2)
P(1)-Pt-C(6)
Fe-Pt-P(1)
Fe-Pt-C(6)
P(1)-Pt-P(2)
P(2)-Pt-C(6)
Fe-Ru-C(4)
C(3)-Ru-C(4)
C(3)-Ru-C(7)
C(5)-Fe-C(7)
Overall, the structure of cluster 8 has features that
are similar to those of the RuPtAu complex [(PPh3)2Pt-
(µ2-CO)RuCpAu(PPh3)2(µ3-η1:η3:η1-CH2CCPh)]+ 31 (VII),
with Ar at this point had no effect on the relative
amounts of 2a and Cp(CO)2FeCH2CtCPh in solution,
even after 18 h. The only change observed by NMR was
13
conversion of Pt(PPh3)2(CO)2 to Pt(PPh3)x (and pre-
sumably also Pt and CO).
When a CD2Cl2 solution of 1a was similarly treated
with CO for 18 h, Cp(CO)2RuC(Ph)dCdCH2 and Pt-
(PPh3)2(CO)2 were formed (eq 9). The characterization
except that the latter contains only one M-M bond.
However, the formation of 8, compared with that of VII
from 1a and [Au(PPh3)]+, involves a more extensive
rearrangement of the metal framework around the C3
hydrocarbyl ligand. In contrast to the formation of 8,
the conversion of VI to 6a , also by the reaction in eq 6,
occurs with only one major structural change, viz.,
replacement of the acyl CO by PtL2.
Rea ction s of Heter obin u clea r Meta l µ-η1:η2
-
r,â
Allen yl Com p lexes w ith CO a n d of Mon on u clea r
Meta l η1-P r op a r gyl a n d η1-Allen yl Com p lexes w ith
P t(P P h 3)2(CO)2. The formation of 3 by replacement of
one PPh3 ligand with CO upon treatment of 1a with Fe2-
(CO)9 (cf. eq 5) prompted us to examine carbonylation
of the former product was described elsewhere.23 No
corresponding η1-propargyl, Cp(CO)2RuCH2CtCPh, was
detected. The reaction can be reversed by passage of Ar
through the solution. However, if the reaction of 1a with

Metal µ-Allenyl Complexes Containing Pt
Organometallics, Vol. 19, No. 16, 2000 3191
CO is conducted for only 2 h, complex 3 and PPh3 are
h to afford 92% isolated 1a . In sharp contrast, heating
Cp(CO)2FeCH2CtCPh and Pt(PPh3(CO)2 in THF at
reflux for 24 h gave only 10% conversion to 2a (in situ
1H NMR characterization).
1
observed as products in high yield by 31P{1H} and H
NMR spectroscopy (eq 10). The reverse of this substitu-
The foregoing reactions of Cp(CO)2MCHdCdCH2 and
Cp(CO)2MCH2CtCPh (M ) Ru, Fe) with Pt(PPh3)2-
(CO)2 may be compared with analogous reactions in-
volving other Pt(0) complexes, including Pt(PPh3)2C2H4
and Pt(PPh3)4. The latter also proceed at ambient
temperature for the η1-allenyls, but require higher
temperatures for the η1-propargyls. The difference in
reactivity may be due to the more extensive rearrange-
ments required for the propargyls compared to the
allenyls, as proposed in the reaction mechanisms de-
picted in Schemes 1 and 2.
Con clu sion s
tion reaction requires heating in toluene at 100 °C for
18 h under Ar. Treatment of 3 with CO at room
temperature for 18 h resulted in the formation of Cp-
(CO)2RuC(Ph)dCdCH2, a small amount of Pt(PPh3)2-
(CO)2, and other mononuclear Pt-containing species.
Passage of Ar through this reaction mixture produced
some 1a , but no detectable 3.
This study has demonstrated that reactions of metal
η1-propargyls with zerovalent metal compounds can be
used for synthesis of heterobinuclear metal µ-η1:η2
-
R,â
allenyl complexes (III). Previously reported products of
such reactions include µ-η3:η2-allenyl/propargyl (I) and
µ3-η1:η2:η2-allenyl (II) complexes.3,4 We have now found
that treatment of Cp(CO)2MCH2CtCPh (M ) Ru, Fe)
with Pt(PPh3)4 or Pt(PPh3)2C2H4 affords (PPh3)2Pt(µ-
η1:η2R,â-C(Ph)dCdCH2)M(CO)Cp (1a , 2a ). The η1-alle-
nyls Cp(CO)2MCHdCdCH2 (M ) Ru, Fe) react with
Pt(PPh3)2C2H4 analogously, and significantly faster than
the η1-propargyls, to yield (PPh3)2Pt(µ-η1:η2R,â-CHdCd
CH2)M(CO)Cp (1b, 2b) (eqs 1, 2). The new heterobi-
nuclear metal complexes show two types of chemical
behavior that are unprecedented for metal µ-allenyls.
First, they serve as precursors of open trinuclear metal
µ3-allenyl products, (PPh3)(CO)Pt(µ3-η1:η2:η2-C(R)dCd
CH2)M′(CO)3M(CO)Cp (M, M′ ) Ru, Fe, 4-7), which are
obtained upon reaction of 1 and 2 with Ru3(CO)12 or Fe2-
(CO)9 (eqs 4, 5). These reactions proceed by insertion of
M′(CO)3 into the Pt-M(CO)Cp bond rather than by
coordination to M′(CO)3 of the free CâdCγ bond of the
µ-allenyl ligand. Second, 1 and 2 display unusual
propensity to fragmentation into mononuclear metal
complexes upon reaction with CO. Accordingly, Cp-
(CO)2MCHdCdCH2 (M ) Ru, Fe), Cp(CO)2RuC(Ph)d
CdCH2, and Cp(CO)2FeCH2CtCPh, as well as Pt(PPh3)2-
(CO)2, are obtained by carbonylation of the appropriate
1 and 2 (eqs 7-9). These reactions are readily reversed
by passage of Ar at ambient temperature into solution
of the η1-allenyl products, but not of the η1-propargyl
product.
Several aspects of the aforementioned reactions invite
further comments. That the CO-induced fragmentation
of 1b and 2b proceeds much more rapidly than that of
1a and 2a appears to be influenced by two factors: (i)
the substituent at the allenyl CR (H or Ph) and (ii) the
nature of the organometallic product (η1-allenyl or η1-
propargyl). That the µ-CHdCdCH2 complexes react
faster than their µ-C(Ph)dCdCH2 counterparts has also
been observed for similar fragmentations of 1a and 1b
induced by fumaronitrile and several alkynes.23 This
reactivity order may be attributed to the expected
stronger M-(η2-C(R)dC) interaction in 1a and 2a than
in 1b and 2b caused by the electron-withdrawing R )
Ph group. However, steric effects associated with the
Ph substituent may also be a contributing factor. The
slower formation of Cp(CO)2FeCH2CtCPh from 2a than
of the appropriate η1-allenyl complexes from 1a ,b and
2b may be ascribed to the apparent requirement of
migration of Fe from CRdCâ to CâdCγ to afford the η1-
propargyl product (cf Scheme 2). However, it is not clear
why 1a yields Cp(CO)2RuC(Ph)dCdCH2, and 2a fur-
nishes Cp(CO)2FeCH2CtCPh upon reaction with CO.
Both Cp(CO)2RuCH2CtCPh and Cp(CO)2FeCH2CtCPh
are stable compounds, but Cp(CO)2FeC(Ph)dCdCH2,
unlike Cp(CO)2RuC(Ph)dCdCH2, has not been re-
ported.
The reverse of the reactions in eqs 7-9 also proceeds
much more rapidly for the Ru and Fe η1-allenyls than
for the η1-propargyl Cp(CO)2FeCH2CtCPh. These and
related reactions were also investigated on a synthetic
scale by use of equimolar amounts of the η1-allenyl or
η1-propargyl complex and Pt(PPh3)2(CO)2. With Cp-
(CO)2MCHdCdCH2 (M ) Ru, Fe) in THF at room
temperature, the reaction was over in 2 h, and excellent
isolated yields (87-90%) of 1b and 2b were obtained.
With Cp(CO)2RuCH2CtCPh, the reaction required re-
flux temperature of THF and reached completion in 2
Ack n ow led gm en t . This investigation was sup-
ported by the National Science Foundation and The
Ohio State University. We thank J ohnson Matthey
Aesar/Alfa for a loan of ruthenium chloride.
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates, thermal parameters, and bond distances and
angles for 1a , 3, 6a , and 8. This material is available free of
charge via the Internet at http://pubs.acs.org.
OM000205G