m-Phenylene-Linked Bis-(Biradicals). Generation, Characterization and Computational Studies

m-Phenylene-linked biscarbenes, bisnitrenes and carbenonitrenes can be formed photochemically from appropriate nitrogenous precursors. Generation of such reactive intermediates under matrix-isolation conditions allows for their characterization by spectroscopic techniques such as ESR, UV/vis and IR. The latter method is also useful in characterizing secondary products derived from these reactive intermediates. Computational chemistry methods complement experimental IR data, aiding, thus, in identification of such compounds. In addition electronic structure calculations help in developing qualitative and semi-quantitative models, which can be useful in predicting ground-state multiplicities. The parent systems of m-phenylene-linked carbenes and nitrenes have high-spin ground states, but a switching to lower multiplicity can be achieved by chemical substitution. The ground state and various low-lying excited states of m-phenylenecarbenonitrenes can be reasonably approximated by simple valence-bond depictions. Finally, m-phenylenecarbenonitrenes are photoreactive in the inert matrix isomerizing to cyclopropene derivatives

Lipidomics and Free Radical Modifications of Lipids

The free-radical-induced modification of biologically relevant molecules is an active field of interdisciplinary research, spanning from chemistry to biochemistry, biology and medicine. Lipid modifications are also attracting attention for their relationship with structural and functional roles in physiological and pathological conditions of living organisms. The discipline of lipidomics studies the lipid behavior in an innovative and multidisciplinary context. Combining lipidomics with free radical chemistry, the research field becomes an ideal setting for the chemical biology approach, to study the basis of molecular mechanisms and chemical reactivity and connect them with free-radical-based processes occurring in the biological environment. This paper will give an overview of the approaches for studying free radical processes on lipids and some biological consequences, which represent also subjects of interdisciplinary collaborations among European research groups and contribute to the general topic of the COST Action 'Free Radicals in Chemical Biology'

Tricyclo­[3.3.1.03,7]nonane-3,7-diyl bis­(methane­sulfonate)

The crystal structure of the title compound, C11H18O6S2, was determined to investigate the effect of the eclipsed mesyl groups on the bond length of the vicinal quaternary C atoms. The two quaternary C atoms of the noradamantane skeleton and the two O atoms to which they are connected all located essentially in the same plane [maximum deviation 0.01 Å], resulting in an eclipsing conformation of the C—O bonds. The C—C bond of the quaternary C atoms is 1.597 (3) Å is considerably longer than the other C—C bonds of the mol­ecule