Spectroscopic and solid state characterization of bimetallic terdentate [C,N,S] thiosemicarbazone Palladium(II) metallacycles with bridging and chelating [P,P] diphosphine ligands

Abstract Bimetallic cyclometallated palladium(II) complexes readily react with silver perchlorate and tertiary diphosphines to give dipalladium compounds with terdentate [ C , N , S ] thiosemicarbazones, and with bridging and chelating [ P , P ] ligands, of the type [Pd(Ph 2 PCH 2 PPh 2 - P , P ){Pd[4-MeOC 6 H 3 C(Me) NN C(S)NHMe](Ph 2 PCH 2 PPh 2 )- P , S }] [ClO 4 ] 2 , 1a . The crystal structures of complexes [PdCl 2 {Pd[2-MeOC 6 H 3 C(Me) NN C(S)NHMe](Ph 2 PC(CH 2 ) 2 PPh 2 )- P , S }] and [Pd(Ph 2 PCH 2 PPh 2 - P , P ){Pd[3-MeOC 6 H 3 C(Me) NN C(S)NHMe](Ph 2 PC(CH 2 ) 2 P-Ph 2 )- P , S }]-[ClO 4 ] 2 , 6 and 4a , respectively, are the first reported examples of palladacycles with the diphosphine Ph 2 PC(CH 2 ) 2 PPh 2 , bis(diphenylphosphine)cyclopropane (dcpc), in the bridging mode. The short-bite diphosphines produce strained four-membered rings at the metal; the structures for 1a and 4a show the P–C–P carbon atom puckered away from the metal coordination plane.