A series of metal acetylacetonates covalently anchored onto amine functionalized silica were prepared by the complexation of metal acetylacetonates [Co(acac) 2 , Cu(acac) 2 , Pd(acac) 2 , Ru(acac) 3 , Mn(acac) 3 , Co(acac) 3 ] with organically modified 3-aminopropyl silica and their catalytic activities were tested for the oxidation of aromatic aldehydes, α,β-unsaturated aldehydes and benzyl alcohols to the corresponding carboxylic acids in aqueous medium. Different metal acetylacetonates have been chosen with a view to select the most active heterogeneous catalyst for oxidations. The characterization of the catalysts was done on the basis of FTIR, TGA and AAS analysis. SiO 2 -Co(acac) 2 catalyzes the oxidation of aromatic aldehydes under air atmosphere without using any additional oxidant; however, t-BuOOH was found to be a highly efficient oxidant for the oxidation of α,β-unsaturated aldehydes and heterocyclic aldehydes, as well as the direct oxidation of benzyl alcohols to the corresponding carboxylic acids. The most active catalyst was found to be highly stable and recyclable under the reaction conditions. † Electronic supplementary information (ESI) available.

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Metals are essential cellular components selected by nature to function in several indispensable biochemical processes for living organisms. Transition metal complexes are important in catalysis, materials synthesis, photochemistry, and biological systems. Medicinal inorganic chemistry can exploit the unique properties of metal ions for the design of new drugs. The use of metals and their salts for medicinal purposes has been present throughout history. With the advancement in the field of inorganic chemistry the role of transition metal complexes as therapeutic compounds is becoming increasingly important. Recent advances in inorganic chemistry have made possible formation of number of transition metal complexes with organic ligand of interest, which can be used as therapeutic agent. This review illustrates the role of metals and the recent progress in the field of medicinal bioinorganic chemistry with new approaches to the design of innovative metal-based drugs and their application.

This paper reports a series of novel metal acetylacetonates covalently anchored onto amine functionalized silica/starch composite, prepared by the Schiff condensation of metal acetylacetonates [Co(acac) 2 , Cu(acac) 2 , Pd(acac) 2 , Ru(acac) 3 , Mn(acac) 3 , Co(acac) 3 ] with organically modified 3-aminopropyl silica/starch composite. Different metal acetylacetonates have been chosen with a view to select the most active heterogeneous catalyst. Among various catalysts, covalently anchored Cu(acac) 2 onto amine functionalized silica/starch composite [ASS-Cu(acac) 2 ] was found to be the most active and recyclable catalyst for the one-pot thioetherification and one-pot three component synthesis of 2H-indazoles via consecutive C-N and N-N bond formations. All the catalysts were characterized by FTIR, TGA and AAS analysis and the most active catalyst, [ASS-Cu(acac) 2 ] was further characterized by SEM and TEM. The catalyst could be recovered by simple filtration and reused with almost consistent activity for four consecutive runs.

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Silica functionalized Mn(acac) 3 was prepared and employed for the one-pot oxidative synthesis of 2-arylbenzimidazoles, 2-arylbenzothiazoles; and oxidation of benzoins to benzils under air atmosphere using water as the reaction medium. Environmentally friendly procedure, chemoselectivity and excellent yields are main advantages of this procedure. In all the cases, the catalyst was found to be highly active and selective; passes hot filtration test successfully; and could be recycled several times with a slight loss of activity.

A series of novel 6-{5-aryl- 4H-1,2,4-triazol-3-ylthio}methyl-3-substituted-[1,2,4]triazolo [3,4-b] [1,3,4] thiadiazoles and 2-{(5-aryl-4H-1,2,4-triazol-3-ylthio)-N-4-aryl}acetamides containing 1,2,4-triazole moiety were synthesized and characterized by 1 H, 13 C, DEPT, and D 2 O. The synthesized compounds were evaluated for their antibacterial activity against three strains of bacteria along with antifungal activity against five fungal species. It has been found that tested compounds showed moderate activity.