Herein, to develop the comprehension of the microbiological activity of metal complexes based on benzaldehyde‐N4‐thiosemicarbazone derivatives, we described the synthesis, characterization of copper(II), zinc(II) and cadmium(II) complexes with vanillin‐4‐methylthiosemicarbazone (MTSVN) and 3,4‐dihydroxybenzaldehyde‐4‐methylthiosemicarbazone (MTSDHB). The crystal structures of the [ZnCl2(MTSVN)2] (L1 C1) and [CdBr2(MTSDHB)2.H2O]2 (L2C5) complexes were determined by the single X‐Ray diffraction method, the central ion is coordinated through the sulphur. For the other complexes, the ion is coordinated through the sulfur as well as azomethine nitrogen atom of the thiosemicarbazone. All these compounds, the two ligands and the new nine complexes were screened in vitro for their antifungal activity against human pathogenic fungi: Candida albicans and Aspergillus fumigatus, and for their antibacterial activity against Gram (+) bacteria such as Bacillus subtilis and Enterococcus faecalis as well as against Gram (−) bacteria such as Paracoccus yeei and Acinetobacter baumanii. By investigating the structure‐activity relationships, we found that the two ligands MTSVN (L1) exhibited significant effect against E. faecalis and A. baumanii and the MTSDHB (L2) acted only against E. faecalis. Furthermore, all the complexes (L1C1–L1C4 and L2C1–L2C5) showed significant antifungal and antibacterial activities against gram‐positive, gram‐negative bacteria, and two fungal human pathogens.

2-propenal semicarbazone (FASC) and CO ll, Ni n, CuII, Zn H and Cd I! chlorides or bromides gave the complexes: [M(FASC)eX2], [M(FASC)2]X2 or [M(FASC)X2] which were characterized starting from elemental analysis and molar conductances. Their structures are discussed on the basis of magnetic moments, infrared and electronic spectra ; in addition, the NMR data are used in the case of Zn H and Cd u species. The main cell parameters are given using X-ray diffraction powder diagrams.

Novel silylated hydroborate clusters comprising the closo-decaborate cage were prepared and characterized by (1)H, (13)C, (11)B, (29)Si NMR and mass spectroscopy ESI. The synthesis of such silylated clusters was achieved using reactive derivatives of [B10H10](2-), [1-B10H9N2](-) and [2-B10H9CO](-). These silylated decaborate clusters constitute a new class of precursors that can be covalently anchored onto various silica supports without any prior surface modification. As a proof of concept, the synthesized precursors were successfully anchored on mesoporous silica, SBA-15 type, in different percentages, where the mesoporous material retained its structure. All materials modified with closo-decaborate were characterized by (11)B and (29)Si solid state NMR, XRD, TEM and nitrogen sorption.

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The copper complexes of 2‐furaldehyde and furan oximes have previously demonstrated potent cytotoxicity, L1210 DNA synthesis inhibition, DNA topoisomerase II inhibition and DNA fragmentation. Currently a series of cobalt metal complexes of 2‐furaldehyde oximes were compared with copper complexes of furan oximes to determine whether the type of metal is important to the cytotoxicity and mode of action of the complexes. The cobalt complexes of furan oximes, like the copper complexes, were shown to be cytotoxic to suspended tumor cell lines, e.g. leukemias, lymphomas, acute monocytic leukemia and HeLa‐S3 uterine carcinoma. The cobalt complexes did not demonstrate dramatic cytotoxicity against the growth of tumors derived from solid human tumor lines. The cobalt complexes preferentially inhibited L1210 DNA synthesis, followed by inhibition of RNA and protein synthesis from 25 to 100 µM over 60 min. These agents, like the copper complexes of 2‐furaldehyde and furan oximes, were inhibitors of DNA polymerase α activity and de novo purine synthesis with marginal inhibition of ribonucleoside reductase and dihydrofolate reductase activities with DNA fragmentation. Unlike the copper complexes, the cobalt complexes did not inhibit L1210 DNA topoisomerase II activity but did reduce thymidylate synthetase activity. Thus, varying the type of metal within the complexes of 2‐furaldehyde and furan oximes produces differences in both cytotoxicity and mode of action. Copyright © 1999 John Wiley & Sons, Ltd.

Objective: The aim of this work was to characterize the antioxidant properties and to evaluate the total phenol content of leaves, bark, pericarp, and pulp extracts of Lebanese Annona squamosa Linn. (A. squamosa),, as well as a total screening of secondary metabolites present in the various plant parts studied. Methods: Two solvent systems were used for extraction: ethanol 80 % and methanol 80 %. The antioxidant activity of different extracts was investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The Total Phenol Content (TPC) of the different plant parts are determined and compared via Folin-Ciocalteu method. The results were presented as the mean of three separate experiments and error bars were used to illustrate standard deviation. Results: The phenolic content was found to be highest in the A. squamosa leaves methanolic and ethanolic extracts (117.2 mg and 112.92 gallic acid extract/g, respectively). The results showed that A. squamosa leaves methanolic and ethanolic extracts display the highest antioxidant activities than the bark, pulp and pericarp extracts, with half-maximal inhibitory concentration values 13.61 and 15.97 μg. ml-1 respectively. Ethanol 80 % and methanol 80 % were found to be efficient for the extraction of phenolic compounds. Conclusion: Results of this study indicate the presence of promising compounds in Lebanese A. squamosa that are able to act as antioxidants and free radical scavengers.

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The synthesis and characterization of Co II , Ni II , Cu II and Cd II complexes with 2-furfuralsemicarbazone (FSC) and 5-methyl 2-furfuralsemicarbazone (MFSC) are reported. These ligands lead to the complexes: [ML 2 X 2 ] or [MLX 2 ] (L = FSC or MFSC) whose structures were determined using elemental analysis, molar conductivity, magnetic measurements, i.r., far i.r. and electronic spectra as well as by n.m.r. FSC and MFSC act as bidentate ligands in most of the Co II , Ni II , Cu II and Cd II complexes. MFSC is a monodentate ligand in [NiBr 2 (MFSC) 4 ].