Photochemical generation of H2NCNX, H2NNCX, H2NC(NX) (X = O, S) in low-temperature matrices

Abstract

The [NH, C, N, O] and the [NH, C, N, S] molecular systems were investigated by computational and matrix-isolation spectroscopic methods. The determination of the equilibrium structures and relative energies by CCSD(T) method was followed by the computation of the harmonic and anharmonic vibrational wavenumbers, infrared intensities, relative Raman activities, and UV excitation energies. These computed data were used to assist the identification of products obtained by UV laser photolysis of 3,4-diaminofurazan and 3,4-diaminothiadiazole in low-temperature Ar and Kr matrices. It is shown that two open-chain HNNCX and HNCNX and one cyclic HNC(NX) (X = O, S) isomers are generated in the case of both systems. Except for HNNCO and HNCNS, the present study reports the first generation and spectroscopic identification of these compounds.

Matrix-isolation study of pseudohalogens and their derivatives

“…Although some new bands with same wavenumber values as in the 254 nm experiments were observed, their intensities were ~50 and ~5 times smaller in the 365 and 313 nm experiments, respectively, compared to the intensity of corresponding bands in the 254 nm experiments. 134 Despite the many possible isomers which can be constructed using these atoms and the amino group, only two of the isomers, aminoisocyanate (H 2 NNCO) and cyanamide-N-sulfide (H 2 NCNS) were generated before. From these two, experimentally observed isomers, only the 1,2,5-thiadiazole-3,4-diamine was prepared following a literature method and the purity of the product was checked using solid-phase IR and Raman spectroscopy (see Figure B1).…”