Triplet potential energy surface for BH 2 N: A DFT study

The triplet potential energy surfaces (PES) for the isomerization and dissociation reactions of BH 2 N isomers was investigated using the DFT/B3LYP method of theory. Thirteen BH 2 N isomer species and two dissociated products were identified, in which five isomerization reactions and four dissociation pathways were found. On the triplet PES, the nonplanar trans ‐iminoborane ( 1 ) can isomerize to the lowest triplet state of planar aminoboranylidene ( 3 ) and the triplet state planar borylnitrene ( 4 ) directly by two three‐membered ring transition states (TS 1–3 and TS 1–4 ), respectively. The cis‐trans isomerization of iminoborane ( 1 and 2 ) by transition state (TS 1–2 ), the internal conversion of 1 and that of 2 by two transition states (TS 1a–1b and TS 2a–2b ) are also considered in the triplet PES. On the other hand, the dissociation product of B–N–H ( 5 ) and H atom can be predicted by the dissociation reaction of nonplanar cis ‐iminoborane ( 2 ) and a planar structure aminoboranylidene ( 3 ) with the transition state of TS 2–5 and TS 3–5 . At the same time, the dissociation product H–B–N ( 6 ) and H atom can be predicted by the dissociation reaction of nonplanar cis ‐iminoborane ( 2 ) and a planar structure borylnitrene ( 4 ) with the transition state of TS 2–6 and TS 4–6 . By analysis of the whole potential energy surface, we can find the isomerization from planar the triplet state aminoboranylidene ( 3 ) to the triplet state planar borylnitrene ( 4 ) is not carried out in one step directly, but achieved in multistep reactions of ( 3 )   TS   1–3→ ( 1 )   TS   1–4→ ( 4 ). © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005