Synthesis, Structure and Spectroscopic Properties of Oxovanadium Tris(3,5-dimethylpyrazolyl)borate Aroylthiourea Complexes

Abstract

Aroylthiourea ligands, 1-aroyl-3-cyclohexyl-3-methylthiourea (HL 1), 1-(2-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL 2), 1-(3-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL 3) and 1-(4-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL 4) were synthesized through a condensation reaction of methylcyclohexylamine and aroylisothiocyanate with a general formula (X-Ph)(CO)NH(CS)N(C 6 H 5)(CH 3) where X = H, o-Cl, m-Cl and p-Cl, fully characterized by CHNS micro elemental analysis, infrared spectroscopy, UV-visible, nuclear magnetic resonance (1 H, 13 C) and X-ray crystallography. 1-(3-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL 3) crystallized in the monoclinic system, a=14.504(3), b=4.9599(11), c=22.325(5) Å, β=98.461(7)°, Z= 4 and V=1588.5(6) Å with space group P2 1 /c. The IR spectra of the ligands exhibits the characteristic v(CO) and v(N-H) at range 1701-1640 cm-1 and 3317-3144 cm-1 , respectively. Whereas the 1 H and 13 C NMR spectra shows the resonances for N-H and-CO groups at range 8.3-8.5 and 160-163 ppm, respectively. A onepot reaction involving the aroylthiourea ligand, oxovanadium(IV) ion and potassium hydrotris(3,5-dimethylpyrazolyl) borate (KTp*) complex gave the desired [oxovanadium(IV)(tris(pyrazolyl)borate)(aroylthiourea)] complexes namely