Hemilability and regioselectivity in palladium and platinum complexes of dppm(E) [E = O, S, Se] ligands

Hemilability and nonrigidity in a series of mixed P^Pdouble bond; length as m-dashE donor ligands where E = O, S, or Se have been studied in palladium and platinum complexes of the type [M{κ2-(dimethylamino)ethylnaphthyl-C,N)}(P^Pdouble bond; length as m-dashE)][SbF6] where P^Pdouble bond; length as m-dashE = Ph2PCH2P(E)Ph2.The role of the donor in hemilability, regioselectivity and the binding preferences of particular donors trans to the metallated carbon atom were also investigated. NMR parameters including couplings to 195Pt and 77Se were investigated for cis and trans isomers. The magnitude of 2J13C–77Se couplings can readily distinguish the cis and trans isomers. A large through-space 13C–77Se 3J coupling was observed in one of the amino methyl groups of the dppm(Se) complexes.