Chelate structures of 5-(H/Br)-2-hydroxybenzaldehyde-4-allyl-thiosemicarbazones (H2L): Synthesis and structural characterizations of [Ni(L)(PPh3)] and [Ru(HL)2(PPh3)2]

The reactions of 5-R-2-hydroxybenzaldehyde-4-allyl-thiosemicarbazone {R: H (L1); Br (L2)} with [MII(PPh3)nCl2] (M = Ni, n = 2 and M = Ru, n = 3) in a 1:1 molar ratio have given stable solid complexes corresponding to the general formula [Ni(L)(PPh3)] and [Ru(HL)2(PPh3)2]. While the 1:1 nickel complexes are formed from an ONS donor set of the thiosemicarbazone and the P atom of triphenylphosphine in a square planar structure, the 1:2 ruthenium complexes consist of a couple from each of N, S and P donor atoms in a distorted octahedral geometry. These mixed-ligand complexes have been characterized by elemental analysis, IR, UV–Vis, APCI-MS, 1H and 31P NMR spectroscopies. The structures of [Ni(L2)(PPh3)] (II) and [Ru(L1H)2(PPh3)2] (III) were determined by single crystal X-ray diffraction.

The reactions of 5-R-2-hydroxybenzaldehyde-4-allyl-thiosemicarbazone {R: H (L1); Br (L2)} with [MII(PPh3)nCl2] (M, n = Ni, 2 and Ru, 3) in a 1:1 molar ratio have given the stable solid complexes [Ni(L)(PPh3)] and [Ru(HL)2(PPh3)2]. While the 1:1 nickel complexes are formed from an ONS donor set of the thiosemicarbazone and the P atom of triphenylphosphine in a square planar structure, the 1:2 ruthenium complexes consist of a couple from each of N, S and P donor atoms in a distorted octahedral geometry.Figure optionsDownload as PowerPoint slide