UV absorption spectra of intermediates generated via photolysis of B(N-3)(3), BCl(N-3)(2), and BCl2(N-3) in low-temperature argon matrices

The UV absorption spectra of B(N-3)(3), BCl(N-3)(2) and BCl2N3 isolated in low temperature argon matrices were measured as the matrices were photolyze d with the loosely focused output of a D-2 lamp. IR spectra were taken simu ltaneously with the UV spectra, and changes in the UV spectra were correlat ed with changes in the IR spectra. A series of bands at 348.0, 353.5, 360.0 , 366.0, 372.5, and 379.5 nm appeared during the photolysis of B(N-3)(3) an d were assigned as a vibrational progression in a bending mode of NNBN. Pho tolysis of BCl(N-3)(2) generated a feature at 408 nm that displayed evidenc e of vibrational structure and a sharp band at 275 nm. The 408 nm absorptio n was tentatively assigned to ClBN2, a three-membered ring compound, and th e 275 nm band as the A(1)II <-- X(1)Sigma transition in BCl. No new UV feat ures were observed during the photolysis of BCl2N3, although the IR spectru m clearly indicated the formation of ClBNCl. These data indicate that ClBNC l has no UV absorption spectrum at wavelengths longer than 240 nm.