Di- and tri-nuclear complexes of palladium(II) containing doubly- and triply-bridging pyridine-2-thionato (pyS) ligands: crystal structure of [Pd3(C6H4CH2NMe2)3(pyS)2][BF4

Abstract

The complex [Pd2Cl2(dmp)2][dmp = 2-(dimethylaminomethyl)phenyl] reacts with 1H-pyridine-2-thione (pySH) or with the 6-methyl substituted derivative (mpySH) in the presence of triethylamine to generate the dinuclear complexes [Pd2(dmp)2(pyS)2] and [Pd2(dmp)2(mpyS)2]. These exist as head-to-tail isomers with folded conformations so that the palladium co-ordination planes are approximately parallel. Fluxional enantiomerisation of the mpyS-bridged compound leading to N-methyl group exchange has been studied. These bridged dimers behave as cyclic bidentate sulphur ligands. [Pd2(dmp)2(pyS)2] reacts with [Pd(dmp)(solvent)2]+ to give [Pd3(dmp)3(pyS)2]+; the X-ray structure of [Pd3(dmp)3(pyS)2][BF4] is reported. The cation contains a cage of three palladium atoms linked by two triply-bridging pyS ligands. Related η3-2-methylallyl trimers and mixed-ligand trimers have also been synthesised by the same method.