Article ID Journal Published Year Pages File Type
1251942 Vibrational Spectroscopy 2012 12 Pages PDF
Abstract

X-ray crystal structures of two isomers C8H11N3O3, 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 CH3 groups lead to change of the unit-cell structure, molecular and intermolecular arrangement. Both structures are monoclinic, space group P21/c and P21/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 NH⋯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.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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