TRANSITION-METAL CHEMISTRY OF MAIN-GROUP HYDRAZIDES .2. A NEW OXIME THIOSEMICARBAZIDE FRAMEWORK AS A NOVEL SN MULTIFUNCTIONAL TRIPODAL LIGAND FOR PALLADIUM(II) - SYNTHETIC AND X-RAY CRYSTAL STRUCTURAL INVESTIGATIONS

Thiosemicarbazide reacted with butane-2,3-dione oxime to give a Schiff-base product HL via the selective reaction of the hydrazine nitrogen atom. The ligating properties of this new oxime thiosemicarbazide ligand L with palladium(II) were investigated and in the complex [PdL(Cl)] 1 the palladium(II) atom is bound in a trimodal, cis arrangement to the oxime nitrogen, hydrazine nitrogen and the sulfur centre. The crystal structure of complex 1 further reveals that the oxime thiosemicarbazide HL has reacted with [PdCl2(PhCN)2] presumably via the elimination of HCI, in the thiol rather than the thione form. The hydrogen-bonding interaction of the oxime hydrogen that caused HL to be a dimer in the solid state is lost upon complexation with palladium(II), giving complex 1 a monomeric structure. X-Ray crystal data; for HL, monoclinic, space group P2(1)/c, a = 11.082(4), b = 12.679(2), c = 6.101(2) angstrom, Z = 4, R = 0.044 and R' = 0.064; 1, triclinic, space group P1BAR, a = 7.660(3), b = 12.972(5), c = 22.325(8) angstrom, alpha = 89.26(3), beta = 81.53(3), gamma = 84.75(3)-degrees, Z = 8, R = 0.045 and R' = 0.064.