INFRARED-SPECTRA OF BORON ATOM-AMMONIA REACTION-PRODUCTS IN SOLID ARGON

Pulsed laser ablated boron atoms were reacted with ammonia during cond ensation at 10 K with excess argon. Reaction products were identified from matrix infrared spectra by isotopic substitution (B-10, B-11 (NH3 )-N-15, ND3), photolysis behavior, and comparison to ab initio calcula ted frequencies. The major primary reaction is insertion to form the [ HBNH2] intermediate, which either dissociates to BH and NH2, eliminat es H or H-2 to give products, or relaxes in the matrix. The major prim ary product is iminoborane, HBNH, a reactive molecule isoelectronic wi th acetylene, and a minor primary product is the photosensitive BNH ra dical. A second boron atom can react with primary products, and the ma jor secondary reaction products are cyclic B2N radical and linear BNBH . These studies show that atomic boron reacts readily with ammonia.