[12120-15-9]  · C38H34P2Pt  · Ethylenebis(triphenylphosphine)platinum(0)  · (MW 747.73)

(nucleophilic metal species that readily undergoes ligand exchange with alkenes2 and alkynes;3 acts as an efficient hydrosilation catalyst;4 oxidatively adds to activated C-X bonds5 and some C-C bonds, enabling rearrangement to occur6)

Physical Data: white solid, mp 126-128 °C (dec).

Solubility: sol benzene, THF, dichloromethane; insol alcohols.

Form Supplied in: commercially available as a white solid.

Preparative Methods: can be prepared by the reduction of [Pt(PPh3)2(CO)3)].PhH with Sodium Borohydride in ethylene saturated EtOH.7

Handling, Storage, and Precautions: the complex can be briefly handled in air and stored indefinitely under nitrogen. Platinum is reported to be of low toxicity.

Complexation with Alkenes.

The title reagent readily undergoes alkene ligand exchange, possibly via the unsaturated L2Pt (L = Ph3P) as the active species. Numerous platinum alkene complexes have been synthesized by this procedure.2,3,8 Electron-deficient multiple bonds are generally more strongly bound, leading to more stable complexes. In some instances, alkene complexation is a preliminary to rearrangement of the carbon framework via the intermediacy of a s bound organoplatinum species (eqs 1 and 2).6,9


The title reagent has been used to catalyze hydrosilation of a variety of functional groups, typically employing 2-4 mol % of catalyst.10-14 In one example, a racemic silane and an alkyne provided a chiral vinylsilane.10 Tanaka has used o-bis(dimethylsilyl)benzene to enable double silation of functional groups. The postulated intermediate formed from the catalyst and silane is a bis(silyl)platinum species (eq 3).11 Aldehydes and ketones have been shown to add silicon across the C=O bond, whereas unsaturated carbonyl compounds undergo 1,2- or a 1,4-addition depending on the steric environment (eq 4).12 Styrene reacts in a 1,1-fashion, presumably via a hydride shift, to afford the gem-disilyl derivative, whereas isoprene reacts in the more usual 1,2-mode (eq 5).11 More recently, silicon polymers have been prepared by employing tetrakis(dimethylsilyl)benzene and diynes (eq 6).3

Insertion into C-X Bonds.

Oxidative addition to alkyl,13 allyl,14 and alkenyl15 C-X bonds (where X = leaving group) occurs readily. Inhibition of the insertions in the presence of radical scavengers suggests a radical mechanism.13 The title reagent adds to gem-dihalomethanes to form stable complexes.16 In the case of dichloromethane, photolysis is required before insertion occurs.17 Addition to allylic C-X bonds occurs anti to the leaving group. This is postulated to be due, in part, to the electron-donating capacity of the triphenylphosphine ligands and the propensity of the complex to dissociate to form the more nucleophilic L2Pt (eq 7).14 An anomolous reaction is the insertion of platinum into the alkenyl C-Cl bond of 1,2-dichloropropene, as opposed to the expected insertion at the allylic position (eq 8).18

1. Comprehensive Organometallic Chemistry; Wilkinson, G.; Stone, F. G. A.; Abel, E. W., Eds.; Pergamon: 1982; Vol. 6, pp 614-690.
2. Gassman, P. G.; Cesa, I. G. OM 1984, 3, 119.
3. Heyns, J. B. B.; Stone, F. G. A. JOM 1978, 160, 337.
4. (a) Uchimaru, Y.; Brandl, P.; Tanaka, M.; Goto, M. CC 1993, 744; (b) Tanaka, M. Uchimaru, Y.; BSF 1992, 129, 667.
5. Blosser, P. W.; Schimpff, D. G.; Gallucci, J. C.; Wojcicki, A. OM 1993, 12, 1993.
6. Grabowski, N. A.; Hughes, R. P.; Jaynes, B. S.; Rheingold, A. L. CC 1986, 1694.
7. Blake, D. M.; Roundhill, D. M. Inorg. Synth. 1978, 18, 120.
8. White, M. R.; Stang, P. J. OM 1983, 2, 1654.
9. Beck, W.; Goetzfried, F.; Chen, M. W. CB 1978, 111, 3719.
10. Gevorgyan, V.; Borisova, L.; Popelis, J.; Lukevics, E.; Foltynowicz, Z.; Gulinski, J.; Marciniec, B. JOM 1992, 424, 15.
11. (a) Tanaka, M.; Uchimaru, Y.; Lautenschlager, H. J. JOM 1992, 428, 1; (b) Tanaka, M.; Uchimaru, Y.; Lautenschlager, H. J. OM 1991, 10, 16.
12. Uchimaru, Y.; Lautenschlager, H. J.; Wynd, A. J.; Tanaka, M.; Goto, M. OM 1992, 11, 2639.
13. Labinger, J. A.; Kramer, A. V.; Osborn, J. A. JACS 1973, 95, 7908.
14. (a) Kurosawa, H.; Ogoshi, S.; Kawasaki, Y.; Murai, S.; Miyoshi, M.; Ikeda, I. JACS 1990, 112, 2813; (b) Jones, M. D.; Kemmitt, R. D. W. CC 1985, 811.
15. Stang, P. J.; Kowalski, M. H.; Schiavelli, M. D.; Longford, D. JACS 1989, 111, 3347.
16. Kermode, N. J.; Lappert, M. F.; Skelton, B. W.; White, A. H.; Holton, J. CC 1981, 698.
17. Scherer, O. J.; Jungmann, H. JOM 1981, 208, 153.
18. Lukas, J.; Visser, J. P.; Kouwenhoven, A. P. JOM 1973, 50, 349.

Francis J. Montgomery

The Ohio State University, Columbus, OH, USA

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