[20436-52-6]  · C12H31ClP2Pt  · trans-Chlorohydridobis(triethylphosphine)platinum(II)  · (MW 467.87) (trans)


(catalyst for nitrile hydration1)

Physical Data: mp 81-82 °C; bp 130 °C/0.01 mmHg; sublimes at 75 °C/0.01 mmHg.

Solubility: sol organic solvents, incl. pentane (avoid chlorinated solvents).

Form Supplied in: white solid; commercially available.

Analysis of Reagent Purity: mp, NMR, IR.

Preparative Method: prepared in three steps from PtCl2.2

Handling, Storage, and Precautions: air stable as the solid.

Nitrile Hydration.

The hydration of nitriles to amides is catalyzed by (Et3P)2PtHCl (1) and the PMe3 analog under mild conditions (80 °C) in the presence of one equivalent of Sodium Hydroxide per Pt (eq 1).1 The maximum rate with acetonitrile occurs at about a 1:1 mixture of water to nitrile (70 and 178 moles amide per mol Pt per hour for Et3P and Me3P complexes, respectively). Phase transfer catalysts can be added to increase the rate with water-immiscible nitriles. Further addition of triethylphosphine also increases the reaction rate. In general, the trimethylphosphine analog appears to give higher rates than the triethylphosphine complex.

The title reagent might have particular value with hydrolysis-sensitive compounds, since the reaction conditions are much milder than those used with acid or base catalysts. The catalyst is particularly selective for hydrolysis of a nitrile in the presence of a conjugated double bond. For instance, conjugate addition of water to the alkenic double bond of acrylonitrile can be minimized, especially at lower temperatures. In addition, compounds which contain esters undergo selective nitrile hydrolysis (eq 2).

Methacrylate Polymerization.

Various trans-PtHX(PEt3)2 species catalyze the polymerization of methyl methacrylate in CCl4.3 The rate follows NO3 > Cl > Br > NO2 > CN. Co-polymerizations of methyl methacrylate with styrene have also been reported.4 The monomer reactivity ratios were 0.50 and 0.65, respectively, and were suggested to proceed via a radical mechanism.

Alkene Hydrogenation.

Catalytic hydrogenation of simple alkenes, both terminal and internal, linear and cyclic, have been accomplished with (1) under ambient conditions in the presence of mineral acid.5

Alkene Hydroformylation.

In the presence of Tin(II) Chloride, (1) catalyzes the hydroformylation of 1-hexene with moderate performance.6

Alkene Hydrosilation.

Complex (1) can function as an alkene hydrosilylation catalyst, but the activity is not as good as other catalysts.7

1. (a) Jensen, C. M.; Trogler, W. C. JACS 1986, 108, 723. (b) Trogler, W. C.; Jensen, M. US Patent 4 684 751 (1987).
2. Phillips, J. R.; Trogler, W. C.; Brammer, M.; Packett, D. L. OS 1992, 29, 189.
3. N. Kameda NKK 1989, 1172 (CA 1989, 111, 174 698j).
4. Kameda, N.; Imamura, Y.; Masatami, T. NKK 1974, 346 (CA 1974, 81, 78 296t).
5. Giustiniani, M.; Dolcetti, G.; Pietropaolo, R.; Belluco, U. IC 1969, 8, 1048.
6. Scrivanti, A.; Paganelli, S.; Matteoli, U.; Botteghi, C. JOM 1990, 385, 439.
7. Skvortsov, N. K.; Trofimov, A. E.; Titov, K. E.; Spevak, V. N.; Vasil'ev, V. V. ZOB 1991, 61, 574.

Timothy T. Wenzel

Union Carbide Corporation, South Charleston, WV, USA

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