Iron(III) complex with N2O2-thiosemicarbazidato and azide ligands. Synthesis mechanism, experimental and theoretical studies

Reaction of acetylacetone-S-methyl-thiosemicarbazone and 4-methoxy-salicylaldehyde in presence of Fe(ClO4)3 and NaN3 resulted in a mixed ligand complex, [Fe(L)N3], where L is N2O2-chelating thiosemicarbazidato ligand formed by template condensation. The first iron complex of the thiosemicarbazidato structure bearing a nitrogen ligand instead of chlorine in the 5th coordination site of iron(III) was characterized by using elemental analysis and spectroscopic methods. Crystallographic analysis clearly revealed the square pyramidal environment of iron(III) center. To support and compare the experimental data, the molecular geometries, vibrational frequencies, NMR chemical shifts, molecular electrostatic potential surface and HOMO-LUMO energies were performed by using DFT-B3LYP method. Formation of the iron(III) complex was explicated by identification the reaction intermediates using experimental and theoretical methods.