Dinitrogen Sulfide, N2S, Revealed by Photoelectron Spectroscopy

Article abstract of DOI:10.1021/ja00219a019

The reactive dinitrogen sulfide molecule, N2S, has been confirmed by He I photoelectron spectroscopic measurements as a major product of the thermal decomposition of 5-phenyl-1,2,3,4-thiatriazole.The adiabatic ionization energy of N2S is 10.55 eV, and its spectrum is characterized by two sharp ionization bands assigned as the ground ²Π (?_s) and first excited ²Σ(?_NN) states of the N2S⁺ ion.A broad band is tentatively assigned to the second excited ²Π (?_NN) ion state.Comparison with the spectrum of its stable analogue, OCS, indicates that the N-S bond is relatively weak, so that the S atom effects only small perturbations of the ?_g and ?_u molecular orbitals of N2 within the linear N2S molecule.Molecular orbital calculations provide data in good agreement with these observations, including estimates of the geomtry and vibration frequencies of N2S and N2S⁺.The photoelectron spectra also show that diatomic sulfur, S2, is produced in the thermal decomposition of 5-phenyl-1,2,3,4-thiatriazole, from which it is concluded that N2S is undergoing bimolecular decomposition.This confirms that N2S is not only just an unstable but also propably a highly reactive 1,3-dipole similar to diazomethane, CH2N2, and potentially useful in chemical synthesis.