J. Lorenc, J. Hanuza, J. Janczak
Mar 1, 2012
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Influential Citations
11
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Journal
Vibrational Spectroscopy
Abstract
Abstract X-ray crystal structures of two isomers C 8 H 11 N 3 O 3 , i.e. 2-N-ethylamino-5-methyl-4-nitropyridine N-oxide (EN5MPO) and 2-N-ethylamino-3-methyl-4-nitropyridine N-oxide (EN3MPO) have been determined. The different substitutions of the CH 3 groups lead to change of the unit-cell structure, molecular and intermolecular arrangement. Both structures are monoclinic, space group P 2 1 / c and P 2 1 / n with a parallel and antiparallel orientation along the a -axis, respectively. In each of the two subunits, the methyl carbons and N-atoms of the nitro group are almost coplanar with the pyridine ring, but the N-oxide bonds are inclined from this plane. The crystal structures are stabilized by a set of the weak inter- and intramolecular hydrogen bonds of the N H⋯O type. The structures of both isomers have been confirmed by the results of IR and Raman spectra measurements, quantum chemical calculations and potential energy distribution (PED). The role of methyl group introduced in 3 or 5 position of 2-N-ethylamino-4-nitropyridine N-oxide has been analysed.