Catalytic oxidative desulfurisation over Co/Fe-γAl2O3 catalyst: performance, characterisation and computational study.

The world faces the challenge to produce ultra-low sulfur diesel with low-cost technology. Therefore, this research emphasised on production of low sulfur fuel utilising nanoparticle catalyst under mild condition. A small amount of cobalt oxide (10-30 wt%) was introduced into the Fe/Al2O3 catalyst through the wet impregnation method. Cobalt modification induces a positive effect on the performance of the iron catalyst. Hence, the insertion of cobalt species into Fe/Al2O3 led to the formation of lattice fringes in all directions which resulted in the formation of Co3O4 and Fe3O4 species. The optimised catalyst, Co/Fe-Al2O3, calcined at 400 °C with a dopant ratio of 10:90 indicating the highest desulfurisation activity by removing 96% of thiophene, 100% of dibenzothiophene (DBT) and 92% of 4,6-dimethyl dibenzothiophene (4,6-DMDBT). Based on the density functional theory (DFT) on Co/Fe-Al2O3, two pathways with the overall energy of -40.78 eV were suggested for the complete oxidation of DBT.

Effect of Cu doping on the photocatalytic activity of InVO4 for hazardous dye photodegradation under LED light and its mechanism.

Cu doped InVO4 (xCu-InVO4 (x = 0.06-0.15 wt %) was synthesized by a facile one-pot hydrothermal method for the removal of methylene blue (MB) under LED light irradiation. The X-ray photoelectron spectroscopy (XPS) analysis indicated the coexistence of V5+ and V4+ species due to the O-deficient nature of the xCu-InVO4. The synthesized photocatalysts displayed a morphology of spherical and square shaped particles (20-40 nm) and micro-sized rectangle rods with a length range of 100-200 µm. The xCu-InVO4 exhibited superior adsorption and photodegradation efficiency compared to pristine InVO4 and TiO2 due to the presence of O2 vacancies, V4+/V5+ species, and Cu dopant. The optimum reaction conditions were found to be 5 mg L-1 (MB concentration), pH 6, and 100 mg of photocatalyst mass with a removal efficiency and mineralization degree of 100% and 96.67%, respectively. The main active species responsible for the degradation of MB were •OH radicals and h+. Reusability studies indicated that the 0.13Cu-InVO4 was deactivated after a single cycle of photocatalytic reaction due to significant leaching of V4+ and Cu2+ species.

Floating ZnO QDs-Modified TiO2/LLDPE Hybrid Polymer Film for the Effective Photodegradation of Tetracycline under Fluorescent Light Irradiation: Synthesis and Characterisation.

In this work, mesoporous TiO2-modified ZnO quantum dots (QDs) were immobilised on a linear low-density polyethylene (LLDPE) polymer using a solution casting method for the photodegradation of tetracycline (TC) antibiotics under fluorescent light irradiation. Various spectroscopic and microscopic techniques were used to investigate the physicochemical properties of the floating hybrid polymer film catalyst (8%-ZT@LLDPE). The highest removal (89.5%) of TC (40 mg/L) was achieved within 90 min at pH 9 due to enhanced water uptake by the LDDPE film and the surface roughness of the hybrid film. The formation of heterojunctions increased the separation of photogenerated electron-hole pairs. The QDs size-dependent quantum confinement effect leads to the displacement of the conduction band potential of ZnO QDs to more negative energy values than TiO2. The displacement generates more reactive species with higher oxidation ability. The highly stable film photocatalyst can be separated easily and can be repeatedly used up to 8 cycles without significant loss in the photocatalytic ability. The scavenging test indicates that the main species responsible for the photodegradation was O2●-. The proposed photodegradation mechanism of TC was demonstrated in further detail based on the intermediates detected by LC-time-of-flight/mass spectrometry (LC/TOF-MS).

Bis{4-[(2-hy-droxy-5-meth-oxy-3-nitro-benzyl-idene)amino]-phen-yl} ether.

The mol-ecule of the title compound, C28H22N4O9, exhibits crystallographically imposed twofold rotational symmetry, with a dihedral angle of 66.0 (2)° between the planes of the two central benzene rings bounded to the central oxygen atom. The dihedral angle between the planes of the central benzene ring and the terminal phenol ring is 4.9 (2)°. Each half of the mol-ecule exhibits an imine E configuration. An intra-molecular O-H⋯N hydrogen bond is present. In the crystal, the mol-ecules are linked into layers parallel to the ab plane via C-H⋯O hydrogen bonds. The crystal studied was refined as a two-component pseudomerohedral twin.

The crystal structure of ((cyclo-hexyl-amino){(Z)-2-[(E)-5-meth-oxy-3-nitro-2-oxido-benzyl-idene-κO]hydrazin-1-yl-idene-κN 2}methane-thiol-ato-κS)(dimethyl sulfoxide-κS)platinum(II): a supra-molecular two-dimensional network.

The PtII atom in the title complex, [Pt(C15H18N4O4S)(C2H6OS)], exists within a square-planar NS2O donor set provided by the N, S, O atoms of the di-anionic tridentate thio-semicarbazo ligand and a dimethyl sulfoxide S atom. The two chelate rings are coplanar, subtending a dihedral angle of 1.51 (7)°. The maximum deviation from an ideal square-planar geometry is seen in the five-membered chelate ring with an S-Pt-S bite angle of 96.45 (2)°. In the crystal, mol-ecules are linked via N-H⋯O, C-H⋯O, C-H⋯N and C-H⋯π inter-actions into two-dimensional networks lying parallel to the ab plane. The conformations of related cyclo-hexyl-hydrazine-1-carbo-thio-amide ligands are compared to that of the title compound.

Synthesis of lignin based composites of TiO2 for potential application as radical scavengers in sunscreen formulation.

Titanium dioxide (TiO2) is added in sunscreens due to its ability to absorb ultraviolet (UV) light. However, upon irradiation of UV light, reactive oxygen species particularly hydroxyl radical which can damage human skin will be generated. In this study, lignin/TiO2 composites were employed to quench the hydroxyl radicals generated by the TiO2. The lignin was extracted from oil palm empty fruit bunch (OPEFB) via kraft and soda pulping processes. The kraft lignin composite was labelled as KL/TiO2 whereas the soda lignin composite was labelled as SL/TiO2. The lignins and the composites were characterized by FTIR, UV spectroscopy, 13C NMR, SEM, EDX, and XRD. The relative hydroxyl radical production of composites and TiO2 were compared through photo-oxidation of coumarin to 7-hydroxycoumarin as a test medium. The effect of types and amounts of lignin used were studied. The KL/TiO2 composite showed the least radical production due to higher phenolic hydroxyl content of kraft lignin. The activity of the hydroxyl radicals will be quenched when it abstract hydrogen atoms from the phenolic hydroxyl groups.

Crystal structure of (E)-N-cyclo-hexyl-2-(2-hy-droxy-3-methyl-benzyl-idene)hydrazine-1-carbo-thio-amide.

The asymmetric unit of the title compound, C15H21N3OS, comprises of two crystallographically independent mol-ecules (A and B). Each mol-ecule consists of a cyclo-hexane ring and a 2-hy-droxy-3-methyl-benzyl-idene ring bridged by a hydrazinecarbo-thio-amine unit. Both mol-ecules exhibit an E configuration with respect to the azomethine C=N bond. There is an intra-molecular O-H⋯N hydrogen bond in each mol-ecule forming an S(6) ring motif. The cyclo-hexane ring in each mol-ecule has a chair conformation. The benzene ring is inclined to the mean plane of the cyclo-hexane ring by 47.75 (9)° in mol-ecule A and 66.99 (9)° in mol-ecule B. The mean plane of the cyclo-hexane ring is inclined to the mean plane of the thio-urea moiety [N-C(=S)-N] by 55.69 (9) and 58.50 (8)° in mol-ecules A and B, respectively. In the crystal, the A and B mol-ecules are linked by N-H⋯S hydrogen bonds, forming 'dimers'. The A mol-ecules are further linked by a C-H⋯π inter-action, hence linking the A-B units to form ribbons propagating along the b-axis direction. The conformation of a number of related cyclo-hexa-nehydrazinecarbo-thio-amides are compared to that of the title compound.

Schiff base-nickel, palladium, and platinum complexes derived from N-cyclohexyl hydrazine carbothioamide and 3-hydroxy-4-methoxybenzaldehyde: Selective antiproliferative and proapoptotic effects against colorectal carcinoma.

The bidentate N-cyclohexyl-2-(3-hydroxy-4-methoxybenzylidene)hydrazine-1-carbothioamide Schiff base ligand (HL) was coordinated to divalent nickel, palladium and platinum ions to form square planar complexes. The nickel and palladium complexes, [NiL2 ], [PdL2 ] form square planar complexes with 2:1 ligand to metal ratio. The platinum complex, [PtL(dmso)Cl] formed a square planar complex with 1:1 ligand to metal ratio. Platinum undergoes in situ reaction with DMSO before complexing with the ligand in solution. The cytotoxicity of HL, [NiL2 ], [PdL2 ], and [PtL(dmso)Cl] were evaluated against human colon cancer cell line (HCT-116), human cervical cancer (Hela) cell line, melanoma (B16F10) cells, and human normal endothelial cell lines (Eahy926) by MTT assay. The [NiL2 ] complex displayed selective cytotoxic effect against the HCT 116 cancer cell line with IC50 of 7.9 ± 0.2 µM. However, HL, [PdL2 ], and [PtL(dmso)Cl] only exhibited moderate cytotoxic activity with IC50 = 75.9 ± 2.4, 100.0 ± 1.8, and 101.0 ± 3.6 µM, respectively. The potent cytotoxicity of [NiL2 ] was characterized using Hoechst and Rhodamine assays. The nickel complex, [NiL2 ], caused remarkable nuclear condensation and reduction in mitochondrial membrane potential. In addition, molecular docking studies confirms that [NiL2 ] possesses significant binding efficiency with Tyrosine kinase. Altogether, the results revealed that [NiL2 ] exhibits cytotoxicity against the cancer cells via Tyrosine kinase-induced proapoptosis pathway. This study demonstrates that the [NiL2 ] complex could be a promising therapeutic agent against colorectal carcinoma.

(E)-2-(2-Hy-droxy-3-methyl-benzyl-idene)-N-methyl-hydrazine-1-carbo-thio-amide: supra-molecular assemblies in two-dimensions mediated by N-H⋯S and C-H⋯π inter-actions.

In the title compound, C10H13N3OS, the azomethine C=N double bond has an E configuration. The phenyl ring and methyl-hydrazine carbo-thio-amide moiety [maximum deviation = 0.008 (2) Å] are twisted slightly with a dihedral angle of 14.88 (10)°. In the crystal, mol-ecules are linked into sheets parallel to the ab plane via N-H⋯S hydrogen bonds and C-H⋯π inter-actions.

Influence of Mg/CTAB ratio on the structural, physicochemical properties and catalytic activity of amorphous mesoporous magnesium silicate catalysts.

This study investigated the physicochemical and catalytic properties of mesoporous magnesium silicate catalysts prepared at various Mg/CTAB ratios (0.25, 0.50, 0.75 and 1.00). The XPS analysis detected a mixture of enstatite and magnesium carbonate species when the Mg/CTAB ratio was 0.25, and 0.50. A mixture of forsterite and magnesium carbonate species were detected when the Mg/CTAB ratio was 0.75 whereas for the Mg/CTAB ratio of 1.00, enstatite and magnesium metasilicate species were detected. A catalyst with the Mg/CTAB ratio of 1.00 demonstrated the highest catalytic activity in the oxidation of styrene. The styrene conversion rate was 59.0%, with 69.2% styrene oxide (StO) selectivity. The H2O2 molecules were activated regio-specifically by the magnesium species to prevent rapid self-decomposition while promoting selective interaction with styrene. All the parameters that influence the styrene conversion and product selectivity were evaluated using analysis of variance (ANOVA) with Tukey's test. The ANOVA analysis showed that the reaction time (h), Mg/CTAB ratio, styrene/H2O2 ratio, catalyst loading (mg) and temperature (°C) affect styrene conversion and product selectivity (StO) significantly (p < 0.05). The oxidation of styrene was well fitted to the pseudo-first-order model. The activation energy, E a of the catalysed styrene epoxidation reaction was calculated to be 27.7 kJmol-1. The catalyst can be reused several times without any significant loss in its activity and selectivity. The results from this study will be useful in designing and developing low cost, high activity catalysts from alkaline earth metals.

Crystal structure of (E)-2-[3-(tert-but-yl)-2-hy-droxy-benzyl-idene]-N-cyclo-hexyl-hydrazine-1-carbo-thio-amide.

In the title compound, C18H27N3OS, the cyclo-hexane ring has a chair conformation. The azomethine C=N double bond has an E configuration. The nearly planar hydrazinecarbo-thio-amide moiety and substituted benzene ring are twisted by 31.13 (5)° relative to each other. The amide moiety and the cyclo-hexane ring are almost perpendicular to each other; a similar conformation was previously observed in reported structures. In the crystal, mol-ecules are linked by N-H⋯S hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif.

6,6'-[(1E,1'E)-Oxybis(4,1-phenyl-ene)bis-(aza-nylyl-idene)bis-(methanylyl-idene)]bis-(2-methyl-phenol): supra-molecular assemblies in two dimensions mediated by weak C-H⋯N, C-H⋯O and C-H⋯π inter-actions.

The title compound, C28H24N2O3, is a flexible Schiff base, having a dihedral angle of 59.53 (5)° between the mean planes of two phenyl rings bounded in the centre by a single O atom. The dihedral angles between the mean planes of the phenyl rings bonded to the central O atom and the mean planes of the terminal methyl-phenol rings are 31.47 (6) and 36.03 (5)°, respectively. The sp2-hybridized character of the azanylylidene groups is confirmed by their bond lengths and bond angles. In the crystal, mol-ecules are linked into centrosymmetric dimers by weak C-H⋯N inter-actions and connected into dimeric chains through weak C-H⋯O inter-actions. These chains are inter-connected into a two-dimensional network parallel to (1[Formula: see text]1) via weak C-H⋯π inter-actions.

Crystal structure of (E)-4-meth-oxy-2-{[(5-methyl-pyridin-2-yl)imino]-meth-yl}phenol.

The mol-ecule of the title Schiff base compound, C14H14N2O2, displays an E conformation with respect the imine C=N double bond. The mol-ecule is approximately planar, with the dihedral angle formed by the planes of the pyridine and benzene rings being 5.72 (6)°. There is an intra-molecular hydrogen bond involving the phenolic H and imine N atoms.

Crystal structure of 2-methyl-N-{[2-(pyri-din-2-yl)eth-yl]carbamo-thio-yl}benzamide.

In the title compound, C16H17N3OS, a benzoyl thio-urea derivative, the planes of the pyridine and benzene rings are inclined to one another by 66.54 (9)°. There is an intra-molecular N-H⋯O hydrogen bond present forming an S(6) ring motif. In the crystal, mol-ecules are linked via pairs of N-H⋯N hydrogen bonds, forming inversion dimers, which are reinforced by pairs of C-H⋯S hydrogen bonds. The dimers are linked via C-H⋯π inter-actions, forming ribbons along [010].

Crystal structure of N-carbamo-thioyl-2-methyl-benzamide.

There are two mol-ecules in the asymmetric unit of the title compound, C9H10N2OS. In one, the dihedral angle between the aromatic ring and the carbamo-thioyl group is 52.31 (7)° and in the other it is 36.16 (6)°. Each mol-ecule features an intra-molecular N-H⋯O hydrogen bond, which generates an S(6) ring and the O and S atoms have an anti disposition. In the crystal, mol-ecules are linked by N-H⋯S and N-H⋯O hydrogen bonds, generating separate [130] and [1-30] infinite chains. Weak C-H⋯O and C-H⋯S inter-actions are also observed.

Crystal structure of 2-methyl-N-[(4-methyl-pyridin-2-yl)carbamo-thio-yl]benzamide.

In the title compound, C15H15N3OS, there is an intra-molecular N-H⋯O hydrogen bond and an intra-molecular C-H⋯S hydrogen bond involving the C=O and C=S bonds which lie on opposite sides of the mol-ecule. The mol-ecule is non-planar with the benzene and pyridine rings being inclined to one another by 26.86 (9)°. In the crystal, mol-ecules are linked by pairs of N-H⋯S hydrogen bonds, forming inversion dimers with an R 2 (2)(8) ring motif. The dimers are linked via C-H⋯S hydrogen bonds, forming slabs parallel to the bc plane.

Crystal structure of 4-methyl-N-[(4-methyl-pyridin-2-yl)carbamo-thioyl]-benzamide.

In the title compound, C15H15N3OS, the dihedral angle between the planes of the benzene and pyridine rings is 26.86 (9)°. Intra-molecular N-H⋯O and C-H⋯S hydrogen bonds both generate S(6) rings. The C=O and C=S bonds lie to opposite sides of the mol-ecule. In the crystal, inversion dimers linked by pairs of N-H⋯S hydrogen bonds generate R 2 (2)(8) loops.

Crystal structure of 3-(4-methyl-phen-yl)-1-phenyl-5-[(E)-2-phenyl-ethen-yl]-1H-pyrazole.

In the title compound, C24H20N2, the dihedral angles between the pyrazole ring and the pendant phenyl, toluoyl and phenyl-ethenyl rings are 41.50 (8), 4.41 (8) and 31.07 (8)°, respectively. In the crystal, inversion dimers linked by a π-π stacking inter-actions between the phenyl-ethenyl rings are observed [centroid-centroid separation = 3.5857 (9) Å].

Crystal structure of 5-[4-(di-methyl-amino)-phen-yl]-3-(4-methyl-phen-yl)-4,5-di-hydro-1H-pyrazole-1-carbaldehyde.

The title compound, C19H21N3O, comprises a central pyrazole ring which is N-connected to an aldehyde group and C-connected twice to substituted benzene rings. The pyrazole ring is twisted on the C-C single bond, and the least-squares plane through this ring forms dihedral angles of 82.44 (5) and 4.52 (5)° with the (di-methyl-amino)-benzene and p-tolyl rings, respectively. In the crystal, weak C-H⋯O hydrogen bonds link mol-ecules into supra-molecular tubes along the b axis.

Crystal structure of 5-(4-meth-oxy-phen-yl)-3-(4-methyl-phen-yl)-4,5-di-hydro-1H-pyrazole-1-carbaldehyde.

In the title compound, C18H18N2O2, the pyrazole ring has a twisted conformation on the CH-CH2 bond. The tolyl ring and the 4-meth-oxy-phenyl ring are inclined to the mean plane of the pyrazole ring by 4.40 (9) and 86.22 (9)°, respectively, while the two aromatic rings are inclined to one another by 88.75 (9)°. In the crystal, mol-ecules are linked via bifurcated C-H⋯(O,O) hydrogen bonds and C-H⋯π inter-actions, forming sheets lying parallel to the ab plane.