Aroylthiourea ligands, 1-aroyl-3-cyclohexyl-3-methylthiourea (HL1
), 1-(2-chloroaroyl)-3-cyclohexyl-3-methylthiourea
(HL2
), 1-(3-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL3
) and 1-(4-chloroaroyl)-3-cyclohexyl-3-methylthiourea
(HL4
) were synthesized through a condensation reaction of methylcyclohexylamine and aroylisothiocyanate with a
general formula (X-Ph)(CO)NH(CS)N(C6
H5
)(CH3
) 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, 13C) and X-ray crystallography.
1-(3-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL3
) 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 P21
/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 13C 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
Tp*VOL1
, Tp*VOL2
, Tp*VOL3
and Tp*VOL4
and all complexes were characterized accordingly. X-ray study showed that
Tp*VOL1
adopted a monoclinic crystal, a=3.415(2), b=19.463(3), c=14.22(3) Å, β=107.411(4)°, Z= 4 and V=3542.7(11)
Å with P21
/c space group. The VO2+ center adopted a pseudo-octahedral geometry O2N3S, with the oxovanadium(IV)
coordinated to the bidentate ligand (X-Ph)(CO)NH(CS)N(C6
H5
)(CH3
) and tridentate Tp* ligands. The results showed
that aroylthiourea ligands behave as bidentate chelate through O and S atom and the Tp* C3v symmetry adds stabilization
to the VO2+ through its protective tripodal geometry.