engleski

Nitrosobenzene Library: Model for Topoelectronic Selectivity in Nitroso-Azodioxide Dimerization

Cross-linking of nitroso benzenes to heterodimers (azodioxides) in case when they are not sterically crowded with large groups in ortho-position, was studied by nmr, UV-VIS, and Raman spectroscopy as well as by powder x-ray crystallography. Because dimerization of nitroso compounds to azodioxides can in principle be used for construction of novel supramolecular structures, as a preliminary investigation it was of interest to study the selectivity of nitrosobenzenes in forming dimers in solid state. As observed by NMR and vibrational spectroscopy, selectivity for cross-linking is quite different in the solid state than in solution because of a considerable influence of packing factors in the former. Selectivities for cross-linking in the solid state in a complex chemical library of monomers was formulated and measured by using simple spectroscopic and diffraction methods as well as by combinatorial approach. For every member of such nitrosobenzene chemical library it is possible to measure and, by using the Tanimoto similarity coefficients, to calculate two selectivity parameters, Chemical Selectivity and Packing Selectivity. Of the two types of selectivities, packing selectivity is correlated with total dipole moments of nitroso monomer molecules, exactly as theoretically predicted. The chemical selectivity is in correlation with the x-component of the molecular dipole, i.e. the axis which is nearly collinear with nitroso group. This method is in principle proposed for more general use in investigations of similar chemical libraries with binary combined components.

nitroso compound dimerization; chemical library; spectral similarity; solid state selectivity

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