Alcohol imination catalyzed by carbon nanostructures synthesized by C(sp2)-C(sp3) free radical coupling

Imines are important intermediates for synthesizing various fine chemicals, with the disadvantage of requiring the use of expensive metal-containing catalysts. We report that the dehydrogenative cross-coupling of phenylmethanol and benzylamine (or aniline) directly forms the corresponding imine with a yield of up to 98%, and water as the sole by-product, in the presence of a stoichiometric base, using carbon nanostructures as the "green" metal-free carbon catalysts with high spin concentrations, which is synthesized by C(sp2)-C(sp3) free radical coupling reactions. The catalytic mechanism is attributed to the unpaired electrons of carbon catalysts to reduce O2 to O2·-, which triggers the oxidative coupling reaction to form imines, whereas the holes in the carbon catalysts receive electrons from the amine to restore the spin states. This is supported by density functional theory calculations. This work will open up an avenue for synthesizing carbon catalysts and offer great potential for industrial applications.

Enzymatic mechanisms of biological magnetic sensitivity

Primary biological magnetoreceptors in living organisms is one of the main research problems in magnetobiology. Intracellular enzymatic reactions accompanied by electron transfer have been shown to be receptors of magnetic fields, and spin-dependent ion-radical processes can be a universal mechanism of biological magnetosensitivity. Magnetic interactions in intermediate ion-radical pairs, such as Zeeman and hyperfine (HFI) interactions, in accordance with proposed strict quantum mechanical theory, can determine magnetic-field dependencies of reactions that produce biologically important molecules needed for cell growth. Hyperfine interactions of electrons with nuclear magnetic moments of magnetic isotopes can explain the most important part of biomagnetic sensitivities in a weak magnetic field comparable to the Earth's magnetic field. The theoretical results mean that magnetic-field dependencies of enzymatic reaction rates in a weak magnetic field that can be independent of HFI constant a, if H << a, and are determined by the rate constant of chemical transformations in the enzyme active site. Both Zeeman and HFI interactions predict strong magnetic-field dependence in weak magnetic fields and magnetic-field independence of enzymatic reaction rate constants in strong magnetic fields. The theoretical results can explain the magnetic sensitivity of E. coli cell and demonstrate that intracellular enzymatic reactions are primary magnetoreceptors in living organisms. Bioelectromagnetics. 38:511-521, 2017. © 2017 Wiley Periodicals, Inc.