Reactions of hydridotrihalostannato complexes of platinum { trans ‐[PtH(SnX 3 )(PR 3 ) 2 ]} with alkenes

An interaction of trans ‐[PtH(SnX 3 )L 2 ] (I, L = PPh 3 , PMePh 2 , PEt 3 ; PBu 3 ; X = Cl, Br) with ethylene, propene and 2‐methylpropene has been studied by means of 31 P and 1 H NMR spectroscopy. The reactions of platinum hydrides I with ethylene are rapid and reversible at −90°C, giving cis ‐[PtR(SnX 3 )L 2 ] (II, R = C 2 H 5 ). The reaction of propene with I (L = PPh 3 , PMePh 2 ) gives II, R = C 3 H 7 . 13 C and 1 H NMR spectra prove the n‐propyl structure for II, L = PMePh 2 , X = Cl. Complexes II irreversibly isomerize into trans ‐[PtR(SnX 3 )L 2 ] between −50° and 0°C. The equilibrium constants and rates are estimated for the reactions of I with alkenes. They decrease as a function of L (PMePh 2 > PPh 3 > PBu 3 > PEt 3 ) and X (Br > Cl). The reactivities of alkenes decrease with increase of steric hindrances at the double bond.