We have generated new heterogeneous catalysts by immobilizing dioxomonoperoxomolybdenum(VI) on amino acid functionalized Merrifield resin, which exhibit excellent activity, stability and selectivity for the oxidation of thioethers and dibenzothiophene (DBT) to the corresponding sulfoxides or sulfones by H 2 O 2 at ambient temperature. The synthetic protocols are high-yielding, halogen-free, environmentally clean and safe, and operationally simple. The catalysts, [MoO 2 (O 2 )(L) 2 ] 2− -MR [L = valine (MRVMo) or alanine (MRAMo) and MR = Merrifield resin] were prepared by reacting H 2 MoO 4 with 30% H 2 O 2 and the respective amino acid functionalized resin, at near neutral pH. The compounds were characterized by elemental analysis, spectral studies (FTIR, Raman, 13 C NMR and 95 Mo NMR, diffuse reflectance UV-Vis and XPS), SEM, EDX, XRD, Brunauer-Emmett-Teller (BET) and TGA-DTG analysis. The easy recyclability of the catalysts for several catalytic cycles without change in activity and selectivity, their complete chemoselectivity towards the sulfur group of substrates bearing other oxidation prone functional groups, are important "green" attributes of these catalysts. † Electronic supplementary information (ESI) available: 13 C NMR chemical shifts and thermogravimetric data, N 2 adsorption/desorption isotherms, FTIR spectra, bar diagram for the recyclability of the catalyst, calculation for the efficiency of H 2 O 2 , characterization of sulfoxides and sulfones. See

An efficient and eco-compatible route for the selective oxidation of a variety of thioethers to the corresponding sulfoxide or sulfone with 30% aqueous H 2 O 2 in water, using newly synthesized peroxoniobium (pNb) complexes as catalysts, is described. The catalysts with formulas Na 2 [Nb(O 2 ) 3 (arg)]·2H 2 O (arg = arginate) (NbA) and Na 2 [Nb(O 2 ) 3 (nic)(H 2 O)]·H 2 O (nic = nicotinate) (NbN) have been synthesized from the reaction of sodium tetraperoxoniobate with 30% H 2 O 2 and the respective organic ligand in an aqueous medium, and these have been comprehensively characterized by elemental analysis, spectral studies (FTIR, Raman, 1 H NMR, 13 C NMR and UV-vis), EDX analysis and TGA-DTG analysis. The density functional theory (DFT) method has been used to investigate the structure of the synthesized pNb complexes. The catalysts are physiologically safe and can be reused for at least six reaction cycles without losing their activity or selectivity. The oxidation is chemoselective for sulfides or sulfoxides leaving the CC or alcoholic moiety unaffected. The developed methodologies, apart from being high yielding and straightforward, are completely free from halogen, organic co-solvent, or co-catalysts.

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Calcineurin (CN) is a major calmodulin binding serine/threonine phosphatase which plays a crucial role in numerous mammalian signal transduction pathways. Calcineurin inhibitors represent a valuable tool for elucidating CN dependent cellular processes. The present work deals with the synthesis and comprehensive characterization of a new polymer anchored peroxo niobium complex, [Nb2(O2)6(carboxylate)2]‐PA (Nb2) [PA=poly(sodium acrylate)], and identification of a set comprising of neat homoleptic as well as polymer immobilized peroxo complexes of vanadium(V) and niobium(V) as potent CN inhibitors. The in‐vitro effect of the complexes on calmodulin mediated dephosphorylation activity of CN was investigated using a physiological substrate of calcineurin, RII‐phosphopeptide as well as a non‐protein substrate p‐nitrophenyl phosphate (p‐NPP). Enzyme kinetic analysis data revealed that the compounds inhibit function of CN via uncompetitive pathway with Ki values ranging between 1–3 μM, suggesting the formation of an enzyme‐inhibitor‐substrate complex during the course of inhibition.