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

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(Ph2PCH2PPh2-P, P){Pd[4-MeOC6H3C(Me) = NN = C(S) NHMe] (Ph2PCH2PPh2)-P,S}] [ClO4](2),1a. The crystal structures of complexes [PdCl2{Pd[(2)-MeOC6H3C(Me) = NN = C(S) NHMe](Ph2PC(CH2)(2)PPh2)-P, S}] and [Pd(Ph2PCH2PPh2-P, P){Pd[3-MeOC6H3C(Me) = NN = C(S) NHMe] (Ph2PC(CH2)(2)P-Ph-2)-P,S}]-[ClO4](2), 6 and 4a, respectively, are the first reported examples of palladacycles with the diphosphine Ph2PC(CH2)(2)PPh2, 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. (C) 2013 Elsevier B. V. All rights reserved.