Mohammad B. Kassim

Methyl 2-(3-benzoylthioureido)acetate

In the title compound, C11H12N2O3S, the methyl acetate and benzoyl groups adopt a cis-trans configuration with respect to the thiono S atom across the C—N bonds. An intramolecular N—H⋯O hydrogen bond is observed. In the crystal packing, molecules are linked by intermolecular N—H⋯S and C—H⋯O hydrogen bonds to form a two-dimensional network lying parallel to (101).

Syntheses, redox and UV–Vis spectroelectrochemical properties of mono- and dinuclear tris(pyrazolyl)borato-oxomolybdenum(IV) complexes with pyridine ligands

Reaction of [Mo VI (Tp Me,Me )(O) 2 Cl] with a variety of pyridine-based ligands [pyridine (py), 4,4′-bipyridine (bpy), 4-phenylpyridine (phpy) and 1,2′-bis(4-pyridyl)ethene (bpe)] in toluene in the presence of Ph 3 P affords the mononuclear oxo-Mo(IV) complexes [Mo(Tp Me,Me )(O)Cl(L)] (L=py, phpy or monodentate bpy; abbreviated as Mo(py) , Mo(phpy) and Mo(bpy) , respectively) and the dinuclear complexes [{Mo(Tp Me,Me )(O)Cl} 2 (μ-L)] (L=bpy, bpe; abbreviated as Mo 2 (bpy) , Mo 2 (bpe) , respectively). The complex Mo 2 (bpy) , together with the by-product [{Mo(Tp Me,Me )(O)Cl} 2 (μ-O)], have been crystallographically characterised. Electrochemical studies on the oxo-Mo(IV) complexes reveal the presence of reversible Mo(IV)/Mo(V) couples at around −0.3 V versus ferrocene/ferrocenium in every case. For the dinuclear complexes Mo 2 (bpy) and Mo 2 (bpe) these redox processes are coincident, indicating that they are largely metal-centred and not significantly delocalised across the bridging ligand. In contrast, Mo 2 (bpe) alone shows two reversible reductions, separated by 320 mV; these could be described as ligand-centred reductions of the bpe bridge, or as Mo(IV)/Mo(III) couples which—because of their separation—are substantially delocalised onto the bridging ligand. UV–Vis spectroelectrochemical studies using an OTTLE cell at 243 K revealed that oxidation of the complexes results in spectral changes (collapse of the Mo(IV) d–d transitions, loss in intensity of the Mo→pyridine MLCT transition) consistent with the formation of a Mo(V) state following metal-centred oxidation, but that one-electron reduction of Mo 2 (bpe) results in appearance of numerous intense transitions more characteristic of a ligand radical following ligand-centred reduction.

N-[(Piperidin-1-yl)carbothioyl]benz­amide

In the title compound, C13H16N2OS, the piperidine ring exhibit a classical chair conformation. In the crystal, the molecules are linked by N—H⋯O hydrogen bonds, forming zigzag chains running parallel to the c axis.

3-(3-Meth-oxy-benzo-yl)-1,1-diphenyl-thio-urea.

The thiono and carbonyl groups in the title compound, C21H18N2O2S, adopt an anti disposition with respect to the central C—N bond. The diphenylamine rings are twisted relative to each other by a dihedral angle of 82.55u2005(10)°. The 3-methoxybenzoyl fragment is twisted relative to one of the diphenylamine rings, forming a dihedral angle of 74.04u2005(9)°. In the crystal, pairs of intermolecular N—H⋯S hydrogen bonds link the molecules into centrosymmetric dimers, forming columns parallel to the a axis.

2-Bromo-N-(dibenzyl-carbamothioyl)benzamide.

The 2-bromobenzoyl group in the title compound, C22H19BrN2OS, adopts an E conformation with respect to the thiono S atom across the N—C bond. In the crystal structure, the molecule is stablized by N—H⋯O intermolecular hydrogen bonds, forming a one-dimensional chain along the b axis.

1-Benzoyl-3-(4-hy­droxy­phen­yl)thio­urea

In the title compound, C14H12N2O2S, the aminophenol and the benzoyl groups adopt a syn–anti configuration with respect to the thiono C=S group across the thiourea C—N. The dihedral angle between the mean planes of the benzoyl and hydroxyphenyl rings is 36.77u2005(8)°. The molecules are stabilized by intramolecular N—H⋯O hydrogen bonds. In the crystal, weak intermolecular C—H⋯O, O—H⋯S and N—H⋯O hydrogen bonds link the molecules into a chain along the c axis.

Sintesis dan Penentuan struktur ligan terbitan N-bromobenzoil-N’-(1,10-fenantrolin-5-il) tiourea

Derivatives of N-bromobenzoyl-N-(1,10-phenanthrolin-5-yl)thiourea were successfully synthesized from the reaction of 1,10phenanthroline with x-bromobenzoylisothiocyanate (x = ortho, meta and para) to give phen-o-BrBT, phen-m-BrBT and phen-pBrBT, respectively. The molecular structures of the derivatives compounds were elucidated based on the crystal structure of Nbromobenzoyl-N-(1,10-phenanthrolin-5-yl)thiourea, CHNS elemental analysis, mass spectrometry, spectroscopic data (infrared, ultraviolet-visible, nuclear magnetic resonance and luminescence) and cyclic voltammetry.The mass spectrum show similar m/z values at 460.9 and 260.0, which represent the molecular ions for [(phen-x-BrBT)-Na] and [BrBT], respectively. The presence of a v(NH) (3389-3599 cm) and the disappearance of ν(NH2) bands from 1,10-phenanthroline-5-amine indicate the formation of the N-bromobenzoyl-N-(1,10-phenanthrolin-5-yl)thiourea. Attachment of a Br atom to the benzoyl moiety reduced the stretching frequency of C=O group by >20 cm compared with phen-BT ligand. The compounds exhibit two π→π* bands at 231 and 269270 nm for the phenanthroline and benzoyl moieties, respectively. The resonance for N-H proton appeared at δ = 11.53-12.49 ppm. In addition, C resonance signals for C=S and C=O groups were recorded at around 182 and 167.39-169.08 ppm, respectively. The synthesis and effect of a Br substitution on the structural and luminescence properties of N-bromobenzoyl-N(1,10-phenanthrolin-5-yl)thiourea derivatives are presented and discussed in this study.

1-Benzoyl-3-(pyridin-2-yl)-1H-pyrazole

In the title compound, C15H11N3O, the dihedral angle betwen the heterocyclic rings is 9.23u2005(5)° and the dihedral angle between the benzoyl and pyrazole rings is 58.64u2005(5)°. In the crystal, inversion dimers linked by pairs of C—H⋯O hydrogen bonds generate R 2 2(10) loops. The dimers stack into a column running parallel to the b-axis direction.

Photocatalytic degradation of bromothymol blue with Ruthenium(II) bipyridyl complex in aqueous basic solution

Ru(II) bipyridyl photocatalyst with the formula, [Ru(bpy)2(o-CH3-bzpypz)](PF6)2] (Ru01) and [Ru(bpy)2(o-Cl-bzpypz)](PF6)2] (Ru02), where bpy = 2,2’-bipyridyl, o-CH3-bzpypz = (3-(pyridin-2-yl)-1H-pyrazol-1-yl)(o-tolyl)methanone and o-Cl-bzpypz = (2-chlorophenyl)(3-(pyridin-2-yl)-1H-pyrazol-1-yl)methanone, has been successfully synthesized and characterized on the basis of C, H, N elemental analysis, IR, UV-Vis and NMR spectroscopy. Both Ru(II) complexes showed Infrared stretching frequencies at 1742-1736u2005cm−1 v(C=O), 1605u2005cm−1 v(C=N) and 842-837u2005cm−1 v(PF). Full geometry optimization of the complex structures were carried out using DFT method with B3LYP exchange-correlation functional and 6-31G (d,p) basis-set for H, C, N, O and Cl; and LAN2LDZ basis set as effective core potential for the ruthenium centre. The highest-occupied molecular orbital (HOMO) energy levels of Ru01 and Ru02 are −5.63 and −5.55 eV, respectively. The photocatalytic properties of the Ru(II) complexes were evaluated by studying the de...

The Reduction Behaviour of Cerium Doped Iron Oxide in Hydrogen and Carbon Monoxide Atmosphere

The reduction behaviour of 3% cerium doped (Ce-Fe2O3) and undoped iron oxide (Fe2O3) by hydrogen in nitrogen (10%,v/v) and carbon monoxide in nitrogen (10%,v/v) atmospheres have been investigate by temperature programmed reduction (TPR). The phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD). TPR results indicate that the reduction of Ce doped and undoped iron oxide in both reductants proceed in three steps reduction (Fe2O3 → Fe3O4 → FeO → Fe) with Fe3O4 and FeO were the intermediate. TPR results also suggested that by adding Ce metal into iron oxide the reduction to metallic Fe by using both reductant gaseous give better reducibility compare to the undoped Fe2O3. The reduction process of Ce and undoped Fe2O3 become faster when CO was used as a reductant instead of H2. Furthermore, in CO atmosphere, Ce-Fe2O3 give complete reduction to metallic iron at 700 0C which about 200 0C temperature lower than other samples. Meanwhile, XRD analysis indicated that Ce doped iron oxide composed better crystallite phases of Fe2O3 with higher intensity and a small amount of FeCe2O4.