Synthesis and Crystal Structures of Cadmium(II) Complexes with 2-Acetylpyridine Schiff Bases of S-Methyldithiocarbazate or 4-Phenyl 3-thiosemicarbazide

摘要

Metal complexes of the Schiff base ligand are of interest due to their unique physico-chemical properties1,2 and major biological activities.3?5 In this regard, we have reported metal (II, IV, and VI, where M(II) = Mn, Co, Ni, M(IV) = V(IV)O, M(VI) = Mo(VI)) complexes of monoor bis-Schiff base ligands derived from the condensation of salicylaldehyde or 2-acetylpyridine with dithiocarbamate or thiosemicarbazide.6 Recently, dinuclear copper(II) complexes, [Cu2(L)2(CH3COO)](ClO4) (L = 2-benzoylpyridine S-methyldithiocarbazate)7 and [Cu2L2(SO4)] (L = di-2- pyridyl ketone N(4), N(4)-(butane-1,4-diyl)thiosemicarbazone)8 were reported. In here, the sulfur atom from Schiff base ligand together with acetate or sulfate oxygen atoms as anion of starting material bridges the two copper(II) ions, respectively. Although many metal(II)-Schiff base complexes have been reported, there are few reports of dimeric Cd (II) complexes connected via a second ligand except the solvent molecule or the counter anion of the metal salt as starting material.9 In this work, we took the thiocyanate, azide, and dicyanoamide as the second ligands, respectively. For metal ions, the second ligands, especially thiocyanate can provide a variety of terminal and/or bridging coordination modes displayed by the linkage isomerism.10 As a part of the longstanding interest in the synthesis and dimension expansion of coordination compounds with mixed NNS donor system, we report herein a mono- and di-nuclear Cd(II) complexes of an acetylpyridine based dithiocarbamate or 4-phenyl-3-thio semicarbazide. Spectroscopic and thermal properties of the complexes are also discussed.