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  1. Wun FML, Muhd Hafizi Zainal, Syahidah Mohd Tahir, Ishak B. Ahmad, Mohammad B. Kassim
    Sains Malaysiana, 2018;47:923-929.
    The presence of two different chromophores in benzothiazole molecule namely benzothiazole and aromatic rings lead to
    interesting chemical and biological properties that attract more researches on the compounds. Three new benzothiazolylbenzoythiourea
    compounds namely 1-(1,3-benzothiazol-2-yl)-3-(benzoylthiourea) (BBT), 1-(1,3-benzothiazol-2-yl)-3-
    (4-chlorobenzoylthiourea) (BBT-4Cl) and 1-(1,3-benzothiazol-2-yl)-3-(4-methoxybenzoylthiourea) (BBT-4OCH3
    ) with
    different electron withdrawing substituents (R) at the para positions on the benzene ring of benzoylthiourea ring have
    been synthesized from the reaction of R-benzoyl isothiocyanate (R= H, Cl, and OCH3
    ) and 2-aminobenzothiazole. The
    compounds were characterized by spectroscopic techniques (infrared, 1
    H proton NMR and UV-Vis). The IR spectra showed
    the frequency signals of n (C=O), n (C=S), n (N-H) at 1664-1673, 1238-1249 and 3031-3055 cm-1, respectively. The 1
    H
    proton NMR spectra showed the presence of N-H amine and amide signals in the region of (12.14-12.35) and (14.17-14.43)
    ppm, respectively. The proton signals of the two benzothiazole and benzoylthiourea moieties appear at 7.08-8.16 ppm.
    A theoretical study based on Density Functional Theory (DFT) and Time-Dependent (TD) DFT was conducted to optimize
    the geometrical structure and investigate the electronic properties of title compounds. The highest occupied molecular
    orbital (HOMO) was found on the benzothiazole moiety; while, the lowest-unoccupied molecular orbital (LUMO) was
    located at the benzoylthiourea fragment. The DFT optimized structures possessed an intramolecular hydrogen bonding
    and the types of para substituents used influenced the properties of hydrogen bonding.
  2. Syahidah Mohd Tahir, Aisha Al-Abbasi, Qurnisha Ghazali, Mohammad B. Kassim, Khuzaimah Arifin
    Sains Malaysiana, 2018;47:1775-1785.
    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.
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