Mechanism of B‐H Redistribution during Reduction of Polyborazylene by Hydrazine

Abstract Density functional theory has been used to elucidate the mechanistic underpinnings of the regeneration of ammonia‐borane (H 3 B−NH 3 , AB ) from polyborazylene (B x N x H x , PBz ) in the presence of hydrazine (H 2 N−NH 2 , Hz ). Herein, borazine (B 3 N 3 H 6 , Bz ) is used as the simplest relevant model of PBz for the regeneration process. Digestion of Bz using Hz was found to occur by a string of Lewis acid base adduct (between B atoms of Bz and Hz molecule) formation and Hz assisted proton transfer processes. Later, B−H bonds of HB(NHNH 2 ) 2 , the Bz digested product, are redistributed to form hydrazine‐borane (H 3 B−NH 2 NH 2 , HzB ) and B(NHNH 2 ) 3 . Redistribution of B−H bonds occurs through hydroboration and concerted proton‐hydride transfer. Another B−H redistributed product, B(NHNH 2 ) 3 , produces HzB as a result of proton and hydride transfer from cis‐diazene ( Dz ), the oxidized product of Hz in presence of O 2 .