G.-F. Zhang, J.-B. She, Y.-L. Dou
Apr 1, 2006
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Zeitschrift für Kristallographie - New Crystal Structures
Abstract
C5H3N3O5, orthorhombic, Pna2\ (no. 33), a = 12.335(4) A, b = 9.636(3) A, c = 5.738(2) A, V = 682.0 A3, Z = 4, Rgf(F) = 0.031, wRreffF2) = 0.085, T = 298 K. Source of material Under stirring, 1.4 g (0.01 mol) 2-hydroxy-3-nitropyridine was dissolved in 2 ml fuming H2SO4 (50 % SO3 content). 1.5 ml mix- ture ® = 1.6 g/ml) of oleum with fuming HNO3 was added slowly and kept below 40 °C. The solution was stirred at RT for 1 h and slowly rised to 90 °C in 2 h, followed by keeping at 90 °C for addi- tional 4 h. The solution was cooled to RT and poured on 20 g ice. 1.05 g (75 %) pale yellow needles were obtained. Single crystals suitable for X-ray diffraction analysis were isolated after several weeks from aqueous solution (m.p. 175-176 °Q. Discussion Pyridone and hydroxypyridine are tautomeric organic molecules. The calculation of two tautomeric forms of unsubstituted hydroxypyridine, benzoid and quinoid structures, resulted in the difference of energies. The benzoid form is slightly more prefera- ble than the quinoid form (1). Nitropyridine and its derivatives have been paid much attention due to their practical applications: 2-hydroxy-3,5-dinitropyridine is extremely important as an inter- mediate for oxidative dyestuffs, medicines or agrochemicals (2), Also some derivatives of the nitropyridine have nonlinear optics property (3). A variety of substituted nitropyridine compounds are used as herbicidal chemicals to control the growth of unde- sired plants (4). 2-Hydroxyl-3,5-dinitropyridine and its metal complexes have higher explosion temperature and lower sensi- tivity. So, they are used as energetic catalysts for solid propellants in order to adjust and improve their trajectory properties (5). The atoms of nitropyridone moiety (including N3, 04, 05) dis- play an almost coplanar configuration with a mean deviation to the least-squares plane of 0.0134 A. The plane through N2, 02 and 03 has a dihedral angle of 12.5° with the above-mentioned plane. The C2—N2, C2—C3 and C4—C5 distances are 1.462(3) A, 1.363(4) A and 1.360(3) A, respectively, which agree well with the corresponding distance in compound 3-nitro-2- pyridone (6). The distances 1.456(3) A for CI—C2 and 1.390(4) A for C3—C4 are slightly longer than the respective dis- tances in 3-nitro-2-pyridone (1.439(3) A and 1.371(4) A, respec- tively), while the distances of 1.223(3) A for CI—Ol and 1.325(4) A for C5—N1 are slightly shorter than the correspond- ing distances in the same compound (1.236(3) A and 1.339(4) A, respectively) (6).