摘要:
Three molybdenum–dinitrogen complexes [MoN2,Mox(N2) and Mo(N2)3] have been synthesized in Kr matrices and characterized by means of the effects of isotopic substitution on the dinitrogen stretching frequencies. The Mo–N force constants calculated from these spectra are found to be 17.21±0.02 mdyn/Å for MoN2 and fr=18.72 mdyn/Å and frr=0.36 mdyn/Å for Mo(N2)3. The Mo complexes appear to be unique in that rapid formation during co-deposition with N2 occurs only upon photoexcitation of the Mo 7S–7P atomic resonance transition situated at 355 nm in Kr matrices. Although minor amounts of the dinitrogen complexes are formed during deposition in the absence of radiation, their concentration is not increased by thermal annealing. Each of the complexes gives rise to its own electronic absorption spectrum. Irradiation into the electronic absorption bands of individual complexes induced selective photodissociation. Photoinduced growth and decomposition studies allowed correlations to be made between the vibrational and corresponding electronic spectra.