Synthesis and structural characterisation of new binuclear Pd(II) complexes with both bridging and terminal pyrazolate ligands

Dinuclear pyrazolato-bridged Pd(II) complexes Pd2L40 and Pd2L41 have been prepared by reacting Pd(Ac)2 and one equivalent of HL0 (3-phenyl-5-(2-pyridyl)pyrazole) or HL1 (3-phenyl-5-(6-methyl-(2-pyridyl))pyrazole. The new complexes have been characterised by elemental analyses, IR, 1H NMR and in the case of PdL14 by single crystal X-ray diffraction methods. This structure shows two palladium atoms bridged by two L1 ligands. The square-planar geometry of each Pd atom is completed by a bidentate chelating L1 ligand. The six-membered dipalladacycle formed by the two Pd atoms and the two bridging pyrazolato ligands adopts a distorted boat-like conformation.