Synthesis and Crystal Structure of a Mn(II) Complex with Thiosemicarbazone Derivative of Pyridine-3-carbaldehyde Showing Unusual Coordination Mode of Tridentate Thiosemicarbazone

1 INTRODUCTION Heterocyclic thiosemicarbazones as well as their metal complexes have been attracting considerable interest due to their biological activities, such as antiviral, antibacterial, antimalarial, antifungal, and antitumoral activities1～5]. This prompted us to carry out structural studies of these complexes to provide a basis for understanding their behaviors in living systems. Although quite a number of investigations on the 2-heterocyclic thiosemicarbazones have ap- peared6…

Synthesis and Crystal Structure of a Mn(II) Complex with Thiosemicarbazone Derivative of Pyridine-3-carbaldehyde Showing Unusual Coordination Mode of Tridentate Thiosemicarbazone

The title complex Mn(HL)4(NCS)2(CH3CH2OH)2 has been achieved via self- assembly by incorporating manganese(II) into pyridine-3-carbaldehyde thiosemicarbazonate ligand, and characterized by elemental analysis and single-crystal X-ray diffraction study. The crystal crystallizes in triclinic, space group P1, with a = 8.896(2), b = 9.530(2), c = 14.520(4) , α = 87.035(4), β = 88.112(4), γ = 69.434(4)o, V = 1150.9(5) 3, Z = 1, Mr = 984.17, Dc = 1.420 g/cm3, μ(MoKα) = 0.612 mm-1, F(000) = 511, the final R = 0.0574 and wR = 0.1547 for 2855 observed reflections with I > 2σ(I). The complex contains one six-coordinated manganese ion connected by two thiosemicarbazide ligands, in which the thiosemicarbazone ligand acts as a monodentate ligand and coordinates to the center metal atoms via the pyridyl nitrogen atoms, two ethanol molecules and two isothiocyanic anions to give rise to a mononuclear structure. The coordination of a po- tentially tridentate thiosemicarbazone in manganese(II) complex without using its sulfur and imine nitrogen sites is unusual. Hydrogen bonds existing in the complex link the different components to stabilize the crystal structure.