Molecular Crystals of Nitraminopyridine N-oxidess
A. Szemik-Hojniak, T. Glowiak,I. Deperasinska, A. Puszko and Z. Talik
Push-pull properties of the NO group in pyridine N-oxide (PNO) derivatives are strongly affected by the sort and the position of substituent in the pyridine ring. A non-linear second order response (NLO) has been found in the acentric crystals of few of the 4-nitropyridine N-oxides. In a newly synthesized series of PNO derivatives, called nitraminopyridine N-oxides (NAPNO), the above-mentioned properties are expected. Five X-ray structures together with their spectral properties have been studied to date. Mostly, they occur as the centrosymmetric dimers although in the case of meta-substitution by the nitramino group (NA) with respect to the NO group, acentric crystals are formed. This work is a continuation of the above issue and its primary purpose was to investigate the crystal and the molecular structure of 6-methyl-2-nitraminopyridine N-oxide (6M). In the second place, effect of dimerization was analyzed by means of semiempirical (PM3) calculations and both findings were compared to other N-oxides of NAPNO series. Their possible application is also proposed.