Structural and vibrational investigation of para-nitraminopyridine N-oxide. A combined experimental and theoretical studies

The X-ray and vibrational spectroscopic analysis of para-nitraminopyridine N-oxide are reported. The crystals of investigated compound belong to P2(1) of the monoclinic system, Z=4, a=3.735 A, b=11.767 A, c=14.679 A and beta=93.27 degrees . Room temperature powder infrared and Raman spectra of the title compound and its deuterated analogue were measured. The molecular structure of p-nitraminopyridine N-oxide has been calculated with the aid of density functional (B3LYP) method with the extended 6-311++G(d,p) basis set. The calculated geometrical parameters of investigated molecule in gas phase were compared with experimental X-ray data. The harmonic frequencies, potential energy distribution (PED) and IR intensities of p-nitroaminopyridine N-oxide and its deuterated analogue were calculated with B3LYP method. The assignment of the experimental spectra has been made on the basis of the calculated PED. The time depend Hartree-Fock (TDHF) method was used for calculations of hyperpolarizability beta coefficient.