Low-temperature matrix isolation of the 1,1-diazene H_2NN. Electronic and infrared characterization

Abstract

We report the photochemical generation of H_2NN (3) in a glass at 80 K and an argon matrix at 10 °K and the isotopically substituted species, D_2NN (3-d_2), H_2N^(15)N (3-^(15)N) and D_2N^(15)N (3-d2, ^(15)N), facilitating the electronic and infrared spectral characterization of 3. Irradiation of carbamoyl azide (4) in a rigid medium (2-methyltetrahydrofuran (2-MTHF) at 80 K) with a 1000-W Xenon lamp through Corning filters CS-7-54 (UV transmitting, visible 440-660 cut-out filters) affords a blue-violet glass. Electronic absorption spectroscopy (80 K) reveals a structured absorption spectrum in the visible (λ_(max) 636 nm) (Figure 1). This is assigned to the n,π* transition for H_2NN. The vibrational progression shows an average spacing of 1300 cm^(-1), presumably the N-N stretching frequency of 81 of H_2NN. Warming the glass to softening (90 °K) results in Joss of the blue-violet species. Irradiation of 4-d_2^(12) affords a similar electronic absorption spectrum.