Synthesis and Spectroscopic Studies of Molybdenum and Tungsten Complexes of N‐Isonicotinyl‐N′‐aryl‐thiosemicarbazides

Abstract

Molybdenum and tungsten complexes of the formula [M₂O₄L₂(H₂O)₂] [where M = Mo(V) or W(V), HL = N‐isonicotinyl‐N′‐phenylthiosemicarbazide (HInptsc), N‐isonicotinyl‐N′‐p‐methylphenylthiosemicarbazide (HInMeptsc), N‐isonicotinyl‐N′‐p‐methoxyphenylthiosemicarbazide (HInMeOptsc), N‐isonicotinyl‐N′‐p‐chlorophenyl‐thiosemicarbazide (HInClptsc)] have been prepared and their structure elucidated on the basis of analytical, molar conductance, magnetic susceptibility, electronic, nuclear magnetic resonance, and infrared spectral data. Molar conductances suggest that the complexes are non‐electrolytes. IR studies indicate mono‐anionic bidentate chelating behavior of the ligands. Magnetic moments are indicative of diamagnetic behavior of the complexes. However, electronic spectra are in accord with an octahedral environment around the metal ions in all the complexes. ¹H and ¹³C NMR spectra of the metal complexes of the ligands HInMeOptsc and HInptsc, respectively, are consistent with the proposed stoichiometry. X‐ray powder diffraction of the complexes shows their amorphous nature.