Synthesis and Spectroscopic Characterization of Some Transition Metal Complexes of 4-Nitro-N-(2-oxo-1,2-dihydropyrimidin-4-ylcarbamothioyl) benzamide (NPB)

Abstract

An isothiocyanate derivative was reacted with cytosine under appropriate reaction conditions to create 4-nitro-N-(2-oxo-1,2-dihydropyrimidin-4-ylcarbamothioyl)benzamide (NPB), a novel ligand. A number of analytical and spectroscopic methods, including as elemental analysis, ¹H NMR, ¹³C NMR, FT-IR, as well as UV–visible spectroscopy, were used to purify and characterize the synthesized ligand. These methods verified the ligand's functional groups and suggested molecular structure. The ligand was then reacted with various divalent metal ions to create a range of transition metal complexes. To ascertain the complexes' structural and electrical characteristics, conductivity experiments, FT-IR spectroscopy, UV-visible spectroscopy, along with magnetic susceptibility investigations were used. Through the use of suitable donor atoms, the ligand and metal ions were successfully coordinated, according to the analytical & spectral data. All complexes were isolated as stable crystalline solids exhibiting different colors depending on the metal ion involved. It was discovered that the metal-to-ligand molar ratio was 1:2, which translates to a (ligand: metal) ratio of 2:1. An octahedral geometry was suggested for the synthesized compounds based on the spectral and analytical data that were obtained. The complexes' overall molecular formula is [M(NPB)₂Cl₂], where M²⁺ = Mn, Co, Ni, Cu, Zn, Cd, & Hg.