Reactions of [C,N,N′]-cyclometallated platinum compounds with phosphines: transphobia and effect of the chloro substituents: Crystal structure of [PtCl(3,5-C6H2Cl2CHNCH2CH2NMe2)(PPh3)2]

The reaction of [C,N,N′]-cyclometallated platinum compounds [PtX(C6H4−nClnCHNCH2CH2NMe2)] (1a–1g) with triphenylphosphine gave either [C,N]-cyclometallated compounds [PtX(C6H4−nClnCHNCH2CH2NMe2)PPh3] (2), in which PPh3 is trans to the imine nitrogen, or compounds [PtX(C6H4−nClnCHNCH2CH2NMe2)(PPh3)2] (4), with cleavage of the metallacycle. The stereochemistry of compounds 2 is the expected one according to the transphobia effect, while formation of compounds 4 takes place only when there is a chlorine atom adjacent to the metallated carbon. An ionic compound 3 has also been obtained using the chelate diphosphine 1,2-bis(diphenylphosphino)ethane. All compounds have been fully characterised including a structure determination for [PtCl(3,5-C6H2Cl2CHNCH2CH2NMe2)(PPh3)2] (4f).