Dipotassium tetra­aqua­bis­[3,5-bis­(dicyano­methyl­ene)cyclo­pentane-1,2,4-trionato(1−)-κN]cobaltate(II)

The title structure, K2[Co(C11N4O3)2(H2O)4], is isotypic with K2[Fe(C11N4O3)2(H2O)4]. The CoII atom is in a distorted octa­hedral CoN2O4 geometry, forming a dianionic mononuclear entity. Each dianionic unit is associated with two potassium cations and inter­acts with adjacent units through O—H⋯N and O—H⋯O hydrogen bonds

Synthesis of N-arylpyridinium salts bearing a nitrone spin trap as potential mitochondria-targeted antioxidants

The generation of excess reactive oxygen species (ROS) in mitochondria is responsible for much of the oxidative stress associated with ageing (aging), and mitochondrial dysfunction is part of the pathology of neurodegeneration and type 2 diabetes. Lipophilic pyridinium ions are known to accumulate in mitochondria and this paper describes a general route for the preparation of nitrone-containing N-arylpyridinium salts having a range of lipophilicities, as potential therapeutic antioxidants. The compatibility of nitrones with the Zincke reaction is the key to their synthesis. Their trapping of carbon-centred radicals and the EPR spectra of the resulting nitroxides are reported

Synthesis of donor–acceptor chromophores by the [2 + 2] cycloaddition of arylethynyl-2H-cyclohepta[b]furan-2-ones with 7,7,8,8-tetracyanoquinodimethane

Arylethynyl-2H-cyclohepta[b]furan-2-ones reacted with 7,7,8,8-tetracyanoquinodimethane (TCNQ) in a formal [2 + 2] cycloaddition reaction, followed by ring opening of the initially formed cyclobutene derivatives, to afford the corresponding dicyanoquinodimethane (DCNQ) chromophores in excellent yields. The intramolecular charge-transfer (ICT) interactions between the 2H-cyclohepta[b]furan-2-one ring and DCNQ acceptor moiety were investigated by UV/Vis spectroscopy and theoretical calculations. The redox behavior of the novel DCNQ derivatives was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which revealed their multistep electrochemical reduction properties depended on the number of DCNQ units in the molecule. Moreover, a significant color change was observed by visible spectroscopy under electrochemical reduction conditions.ArticleORGANIC & BIOMOLECULAR CHEMISTRY. 10(12):2431-2438 (2012)journal articl

Metal-organic frameworks as heterogeneous catalysts for oxidation reactions

In this Perspective, we describe the use of metal-organic frameworks (MOFs) as heterogeneous catalysts for oxidations using hydroperoxides or molecular oxygen. These two types of oxidants fulfill the requirements of green chemistry in terms of environmental benignity and sustainability. For the sake of clarity and to illustrate the possibilities of using MOFs as oxidation catalysts, we have constrained ourselves to present the results obtained for the oxidation of cycloalkanes, oxidation of benzylic positions, oxidation of cycloalkenes and aerobic oxidation of alcohols. The use of MOFs as catalysts for enantioselective oxidations has been dealt with in a separate section in which the peculiarity of the required oxidants and the advantages of having homo chiral MOFs have been discussed. The key features of MOFs as catalysts, the similarities with inorganic porous solids and future developments in this field have been discussed in separate sections.Financial support by the Spanish DGI (CTQ2009-11587 and CTQ2010-18671 and Consolider MULTICAT) is gratefully acknowledged. Funding of European Commission through an integrated project (MACADEMIA) is also acknowledged.Amarajothi, DM.; Alvaro Rodríguez, MM.; García Gómez, H. (2011). Metal-organic frameworks as heterogeneous catalysts for oxidation reactions. Catalysis Science and Technology. 1(6):856-867. https://doi.org/10.1039/c1cy00068cS8568671