Stable Spiro-Fused Diarylaminyl Radicals: A New Type of a Neutral Mixed-Valence System.

A new type of neutral mixed-valence system was synthesized using a facile one-pot procedure. The spiro-conjugated framework is additionally "fastened" with a biphenyl bridge, which does not directly participate in spin delocalization but makes the molecule stable and influences the reorganization energy and the energy barrier of the intramolecular electron transfer. The in-depth experimental and quantum-chemical study allowed determining the radicals as the Class II Robin-Day-mixed-valence systems. The structure of the radicals was confirmed by the X-ray data, which are relatively rare for Class II MV molecules. Advanced properties of the radicals, such as an ambipolar redox behavior and panchromatic absorption in the visible and NIR regions, along with their stability, make them of interest for materials science. All radicals demonstrate the SOMO-HOMO inversion phenomenon, which was supported by the DFT and the experimental study.

Reversibly switchable methanofullerene by photoexcitation and reduction.

A cyclopropanated derivative of the trifluoromethylated fullerene Cs-C70(CF3)8 demonstrates reversible switching behavior triggered by excited state electron transfer or by negative charging. The switching between the state with connected 62-electron π-system and the state with disjoint 28- and 32-electron conjugated caps is effected by opening/closure of the cyclopropanated bond. A pronounced alteration of the electronic properties upon seemingly minor changes in a large fullerene molecule is an attractive feature for the organic electronic devices where similar fullerene compounds are commonly utilized as electron acceptor materials.

Three Month Heterochronic Parabiosis Has a Deleterious Effect on the Lifespan of Young Animals, Without a Positive Effect for Old Animals.

Our previous study showed that an exchange of blood between heterochronic parabionts for 3 months did not rejuvenate the immune system of the old partners. Moreover, the young immune system became more aged and began to function according to the "old" principle. Does this forced aging affect all systems of the organism in this model? We checked the levels of corticosterone, testosterone, insulin-like growth factor 1 (IGF-1), insulin, and thyroxine in the blood of heterochronic parabionts, but did not find significant changes compared with age-related controls. Since numerous data support the possibility of rejuvenation of the brain, muscles, and other tissues using the model of heterochronic parabiosis, as well as opposite data, we planned to assess the overall effect of this long-term blood exchange on the rate of organism aging. We measured the life span of animals whose blood was exchanged for 3 months and then were disconnected. Median and maximum life expectancy decreased in young heterochronic parabionts compared with the isochronic control. Old heterochronic parabionts showed only a small trend toward an increase in the median life span, but it was not statistically significant, and the maximum life span did not change compared with the isochronic parabionts. These data support our assumption that old blood contains factors capable of inducing aging in young animals. The mechanism of selective suppression of aging factor production in the organism could be a key research field for life extension.

Electrochemically Induced Dimerization of p9mp-C70(CF3)12 Trifluoromethylated Fullerene.

We report a comprehensive study of a novel isomer of C70(CF3)12, p9mp-C70(CF3)12, whose electrochemical behavior differs from most of the other trifluoromethylated fullerenes. The addition pattern of p9mp-C70(CF3)12 is established by means of 19F-19F COSY NMR spectroscopy and DFT calculations. Like p7mp-C70(CF3)10, the new isomer p9mp-C70(CF3)12 undergoes dimerization to the [C70(CF3)12]22- upon single-electron reduction. The electrochemical observations are supported by the DFT calculations of dimerization energy and the temperature dependence of the CW X-band EPR spectroscopy data. Experimentally determined dimerization energies of p9mp-C70(CF3)12-• and p7mp-C70(CF3)10-• in solution are ca -8 and -26 kJ mol-1, respectively, in good correspondence with DFT data.