Infrared Detection of Diimide, N2H2, and Imidogen, NH, by the Matrix Isolation Method

Abstract

Infrared and Raman spectra of solid and matrix isolated diimide, HNNH Hydrazoic acid labeled with deuterium and IoN was photolyzed in solid nitrogen at 20oK. The IoN multiplet splitting positively identifies absorptions of photolysis products as those of trans-N2H2 (at 1286 cm-I ) , trans-HNND (at 1481 and 1058 em-I), trans-N2D2 (at 946 cm-I ), and cis-N2H2 (at 3074 and 1279 em-I).The spectrum of trans-N2H2 is in agreement with a planar symmetric structure and the vibrational frequencies are quite close to corresponding vibrations of ethylene.Imidogen, NH, was also observed in both solid argon and in solid nitrogen as another photolysis product. The IoN splitting in the ammonia absorptions shows that the ammonia dimer in solid nitrogen has a cyclic structure.

Benchmark ab initio thermochemistry of the isomers of diimide, N2H2, using accurate computed structures and anharmonic force fields

“…Experimental information on the cis isomer is quite limited, basically consisting of tentative assignments of bands at 3074 and 1279 cm −1 by Rosengren and Pimentel (RP) [4] and of bands at 1034, 1347, 3025, and 3116 cm −1 by Wiberg, Fisher, and Bachhuber (WFB) [16].…”

“…The trans isomer was finally discovered in 1958 by mass spectrometry as a gaseous discharge product of hydrazine [2], and around the same time in the infrared as a photolysis product of matrix isolated hydrazoic acid [3,4]. The compound is of importance in organic chemistry for the stereospecific reduction of olefins [5] and of course as the parent of a large number of azo compounds, and in inorganic chemistry as a ligand for transition metal complexes [6].…”

Ground state and vertical excitation energies of the diazene isomers with the coupled cluster method

“…This small molecule can exist in the HNNH form, called 1,2-diazene and NNH 2 form called isodiazene. In addition, the 1,2-diazene can assume a trans or cis form, although experimentally only NNH 2 and trans HNNH forms are observed. The diazene was discovered in 1958 [1] and since that time it has undergone Correspondence to: S. Kucharski; e-mail: sak@ich.us.edu.pl In honour of Professor Karol Jankowski on the occasion of his 70th birthday.…”

“…many experimental measurements and theoretical calculations. The evidence of the two existing forms are mainly of spectroscopic nature, i.a., there were several attempts to obtain the IR [2][3][4] spectra.…”

Quantum mechanics of diatomic molecules: overlap integrals, coulomb integrals and ab initio calculations on imidogen

“…The imidogen molecule has been produced in the laborato ry (10-26) by the thermal decomposition of hydrazoic acid NgH (10,11), by the uv photochemical decomposition of N^H (12), by passing an electrical discharge through N^H (13), by the photolysis of N^H (16)(17)(18), by decomposing hydrazine N^H^ (14,19,20), by the photochemical decomposition of ammonia (15,21), and by photolysing isocyanic acid,HNCO (22,23). Imidogen has also been produced by shock wave studies of mixtures of nitrogen and hydrogen (24,25) and by the shock heating of ammonia (25,26).…”