Single-step co-deposition of nanostructured tungsten oxide supported gold nanoparticles using a gold–phosphine cluster complex as the gold precursor

The use of a molecular gold organometallic cluster in chemical vapour deposition is reported, and it is utilised, together with a tungsten oxide precursor, for the single-step co-deposition of (nanostructured) tungsten oxide supported gold nanoparticles (NP). The deposited gold-NP and tungsten oxide supported gold-NP are highly active catalysts for benzyl alcohol oxidation; both show higher activity than SiO2 supported gold-NP synthesised via a solution-phase method, and tungsten oxide supported gold-NP show excellent selectivity for conversion to benzaldehyde

Single-step co-deposition of nanostructured tungsten oxide supported gold nanoparticles using a gold-phosphine cluster complex as the gold precursor

The use of a molecular gold organometallic cluster in chemical vapour deposition is reported, and it is utilised, together with a tungsten oxide precursor, for the single-step co-deposition of (nanostructured) tungsten oxide supported gold nanoparticles (NP). The deposited gold-NP and tungsten oxide supported gold-NP are highly active catalysts for benzyl alcohol oxidation; both show higher activity than SiO2 supported gold-NP synthesised via a solution-phase method, and tungsten oxide supported gold-NP show excellent selectivity for conversion to benzaldehyde

Facile synthesis and characterization of novel dicarboxylate-Cu based MOFs materials

This work describes the synthesis and characterization of benzylimidazole (Bim) and piperazine (P) based metal organic framework (MOF) materials with two different linkers of adipic acid (A) and terephthalic acid (T) namely: ABim-Cu-MOF, TBim-Cu-MOF, AP-Cu-MOF, and TP-Cu-MOF. The physical and chemical characterization of these MOF materials were studied by elemental analysis (CHN), Fourier-transform infrared spectrometry (FT-IR), powder x-ray diffraction (PXRD), BET surface area and thermogravimetric analyses. The synthesized MOF materials were used as a modifier for carbon paste electrode to study its electrochemical behaviour towards ferricyanide. The electrochemical characterization revealed that the newly synthesized MOFs offer an excellent potential as electrode modifier for the redox reaction of ferricyanide. The reaction was reversible and diffusion controlled with the calculated diffusion coefficient values in the range of (4.86 × 10−5–2.66 × 10−5 cm2 s−1). © 2019 Elsevier B.V

Combined xanthorrhizol-curcumin exhibits synergistic growth inhibitory activity via apoptosis induction in human breast cancer cells MDA-MB-231

Background: It has been suggested that combined effect of natural products may improve the treatment effectiveness in combating proliferation of cancer cells. The present study was undertaken to evaluate the possibility that the combination of xanthorrhizol and curcumin might show synergistic growth inhibitory effect towards MDA-MB-231 human breast cancer cells via apoptosis induction. The effective dose that produced 50% growth inhibition (GI50) was calculated from the log dose-response curve of fixed-combinations of xanthorrhizol and curcumin generated from the sulforhodamine B (SRB) assay. The experimental GI50 value was used to determine the synergistic activity of the combination treatment by isobolographic analysis and combination-index method. Further investigation of mode of cell death induced by the combination treatment was conducted in the present study. Results: Isobole analysis revealed that substances interaction was synergistic when xanthorrhizol and curcumin were added concurrently to the cultures but merely additive when they were added sequentially. The synergistic combination treatment was then applied to the cultures to investigate the mode of cell death induced by the treatment. Immunofluorescence staining using antibody MitoCapture™ revealed the possibility of altered mitochondrial transmembrane potential, which is one of the hallmark of apoptosis. Hoechst 33258 nuclear staining assay showed the rate of apoptosis of MDA-MB-231 cells to increase in response to the treatment. Apoptotic cell death was further confirmed by DNA fragmentation assay, where internucleosomal excision of DNA was induced upon treatment with xanthorrhizol-curcumin. Conclusion: This isthe first time the combined cytotoxic effect of xanthorrhizol and curcumin on MDA-MB-231 cells has been documented and our findings provide experimental support to the hypothesis that combined xanthorrhizol-curcumin showed synergistic growth inhibitory activity on MDA-MB-231 cells via apoptosis induction

Synthesis, cytotoxicity and antineoplastic activities of novel acridine-based platinum(II) organometallic complexes

Two new platinum(II) complexes incorporating acridine ligands with aniline moieties were successfully synthesised and characterised. The acridine-based ligands were synthesised by means of Ullmann's condensation. The reaction of cis-[PtCl2(DMSO)2] with the aforementioned ligand in a specified mol ratio gives 9-phenylaminoacridine cis-dichloro(dimethylsulfoxide)-platinum(II), 2a, and bis-[N-(3,5-dimethoxyphenyl) acridin-9-amine)]chloro platinum(II), 2b. Apparently, both complexes were slightly planar and in discrete asymmetrical units. Cytotoxicity and antineoplastic activity evaluations were conducted using WRL-68, MCF-7, HT-29, and HL60 cell lines. The novel complexes exhibited potent activity towards the cell lines. Concurrently, the MTT cytotoxicity assay revealed that all complexes significantly inhibited the proliferation of MCF-7 and HL60 cells. © 2019 Elsevier B.V

Following the Creation of Active Gold Nanocatalysts from Phosphine-Stabilized Molecular Clusters

The phosphine-stabilized gold cluster [Au₆(Ph₂P-<i>o</i>-tolyl)₆]­(NO₃)₂ is converted into an active nanocatalyst for the oxidation of benzyl alcohol through low-temperature peroxide-assisted removal of the phosphines, avoiding the high-temperature calcination process. The process was monitored using in situ X-ray absorption spectroscopy, which revealed that after a certain period of the reaction with tertiary butyl hydrogen peroxide, the phosphine ligands are removed to form nanoparticles of gold which matches with the induction period seen in the catalytic reaction. Density functional theory calculations show that the energies required to remove the ligands from the [Au₆L_<i>n</i>]²⁺ increase significantly with successive removal steps, suggesting that the process does not occur at once but sequentially. The calculations also reveal that ligand removal is accompanied by dramatic rearrangements in the topology of the cluster core

Synthesis, characterization, and evaluation of silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine as biological agents

Five new silver(I) complexes were synthesized with mixed ligands of thiosemicarbazone derivatives and diphenyl(p-tolyl)phosphine in search of new biologically active compounds. A CHN elemental analysis, powder X-ray diffraction (PXRD) data and several spectroscopic techniques such as Fourier-transform infrared spectroscopy, energy-dispersive X-ray, 1 H, 13 C, and 31 P{ 1 H} NMR were performed to elucidate the structure of these complexes. Elemental analysis suggested that the stoichiometry of the complexes formed by the reaction of silver nitrate with thiosemicarbazone in the presence of (p-tolyl)PPh 2 was indeed 1:2:1 molar ratio. The silver ions were discovered to be coordinated to the sulfur of thiosemicarbazone and phosphorus of (p-tolyl)PPh 2 , having a tetrahedral geometry based on the spectroscopic data obtained. The PXRD patterns were studied to see the degree of crystallinity of the complexes. The in vitro antiproliferative activity of these complexes was investigated toward the MDA-MB-231 and MCF-7 breast cancer cell lines, as well as the HT-29 colon cancer cell line, which yielded IC 50 values in low micromolar range. The antiplasmodial activity of these complexes was also examined against chloroquine-resistant Plasmodium falciparum parasite which demonstrated good activity and further tested for their selectivity index. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group

New Silver Complexes with Mixed Thiazolidine and Phosphine Ligands as Highly Potent Antimalarial and Anticancer Agents

Five silver(I) complexes containing a mixed ligand system of phosphine and thiazolidine were successfully synthesized. The structural information of the complexes was assembled using various spectroscopic techniques such as CHN elemental analysis, Fourier transformed infrared (FTIR), 1 H, 13 C, and 31 P{ 1 H} NMR spectroscopy, and thermogravimetric analysis (TGA). A bidentate phosphine ligand acted as a chelating agent which bond to the silver in 1: 2 molar ratios. Meanwhile, thiazolidine was attached to the silver in a 1: 1 molar ratio. The antiplasmodial properties of all synthesized complexes were investigated on chloroquine-resistant P. falciparum parasite via HRP2 assays and cytotoxicity tests on Vero cells. Of all the synthesized complexes, complex 2 showed the highest SI value (more than 12.4) followed by complex 5 (6.6). The potent properties of compounds 2 and 5 were also noted in the in vitro antiproliferative assays involving MDA-MB-231 and MCF-7 breast cancer cell lines as well as HT-29 colon cancer cell line. Complex 2 was selective for MDA-MB-231 cells (GI 50 = 1.9 ± 0.3 μM), while complex 5 acted predominantly on breast carcinoma cells (GI 50 MDA-MB-231 = 4.7 ± 1.1 μM; MCF-7 = 2.9 ± 0.9 μM) instead of colon carcinoma (HT-29) cells (GI 50 = 15.1 ± 1.9 μM)