6-Nitro-[1,10]phenanthroline-1-ium nitrate: crystal structure, ab initio calculations and protonation character

The title compound, 6-nitro-[1,10]phenanthroline-1-ium nitrate, has been synthesized and characterized by elemental analysis, electron absorption spectroscopy, IR, 1H and 13C NMR spectroscopy. The X-ray crystal structure study showed that the compound crystallizes in the monoclinic system, space group Cc; with Mr ¼ 288:22 (C12H8N4O5), a ¼ 13:861ð3Þ; b ¼ 10:142ð2Þ; c ¼ 8:7320ð17Þ A ° , b ¼ 103:70ð3Þ8; V ¼ 1192:6ð4Þ A ° 3, Z ¼ 4; Dc ¼ 1:605 g/cm3, Fð000Þ ¼ 592; m(Mo Ka) ¼ 0.129 mm21, R ¼ 0:0439; wR ¼ 0:1125; GOF ¼ 1.110. In the crystal lattice, the molecules create a network structure through hydrogen bonds. Ab initio calculations of the structures, charges distribution, natural bond orbitals, topological analysis and thermodynamic functions of 5-nitro-[1,10]phenanthroline and its protonated cation were performed at HF/6-311G** and B3LYP/6-311G** levels of theory. The calculation results are in a good agreement with the X-ray data and show that the protonated structure is stable. The calculation of second order optical nonlinearity was carried out and a higher molecular hyperpolarizability of 24.66 £ 10230 esu was predicted. q 2003 Elsevier B.V. All rights reserved.