Synthesis and characterization of diphenylether-based oxime ligands containing unilaterally substituted 1,3,4-thiadiazole groups and investigation of their some transition metal complexes

Abstract

In this study, we synthesized six novel oxime ligands derived from substituted 1,3,4-thiadiazoles, along with their corresponding monomeric transition metal complexes involving Co²⁺, Ni²⁺, and Cu²⁺ ions. Comprehensive structural characterizations were then performed to analyze these compounds. To achieve this, 4-(chloroacetyl) diphenyl ether was synthesized by reacting diphenyl ether with chloroacetyl chloride using a Friedel–Crafts reaction. The starting oxime compound, (E)-N-hydroxy-2-oxo-2-(4-phenoxyphenyl)acetylmidoyl chloride, was synthesized by reacting 4-(chloroacetyl) diphenyl ether with butyl nitrite in a 1:1 molar ratio, with HCl as the catalyst. The target oxime compounds were subsequently synthesized by reacting substituted 2-amino-1,3,4-thiadiazole derivatives with (E)-N-hydroxy-2-oxo-2-(4-phenoxyphenyl)acetylmidoyl chloride, following established procedures from the literature. The structural characterizations of all synthesized organic compounds were carried out using elemental analysis, FTIR spectroscopy, ¹H and ¹³C NMR spectroscopy, and mass spectrometry. The target complexes were synthesized by reacting the ligands with MCl₂·nH₂O salts (M = Co²⁺, Ni²⁺, Cu²⁺). Their structures were confirmed using FTIR spectroscopy, magnetic susceptibility measurements, elemental analysis, and ICP-OES.