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

• Dinuclear 1:2 electrolyte palladacycles with bridging and chelating diphosphines.
• A thorough discussion of the 31P NMR δP and J values.
• First X-ray crystallographic study with bridging Ph2PC(CH2)2PPh2.
• Study of the π⋯π and C–H⋯X intra- and intermolecular interactions in the solid state.

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)NNC(S)NHMe](Ph2PCH2PPh2)-P,S}] [ClO4]2, 1a. The crystal structures of complexes [PdCl2{Pd[2-MeOC6H3C(Me)NNC(S)NHMe](Ph2PC(CH2)2PPh2)-P,S}] and [Pd(Ph2PCH2PPh2-P,P){Pd[3-MeOC6H3C(Me)NNC(S)NHMe](Ph2PC(CH2)2P-Ph2)-P,S}]-[ClO4]2, 6 and 4a, respectively, are the first reported examples of palladacycles with the diphosphine Ph2PC(CH2)2PPh2, 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.

New dinuclear palladium complexes derived from bidentate P,S palladacycle metaloligands are described, which include the first reported examples of palladacycles with the diphosphine Ph2PC(CH2)2PPh2, bis(diphenylphosphine)-cyclopropane (dcpc), in the bridging mode.Figure optionsDownload as PowerPoint slide