![]() A trilithiated derivative of BsH6+ (4a) is found to prefer a planar structure. Theoretical studies using ab initio MO calculations on for X = H, F, and Li (1-3) and (4) were performed to this end. The effects of x-substituents such as the halogens on lithioboranes were also studied in detail5 It occurred to us that fluorine and lithium substitution could have a large influence on the structure and stability (in particular the ASE) of the threemembered borocyclic ring. ![]() A recent study on R2BLi (R = H, CH3, NH2, OH, and F) by Wagner et aL5 suggested lithioboranes to be moderately polar molecules with significant covalent character for the B-Li bond. The aromatic stabilization energy (ASE) deduced from an isodesmic equation suggests a value of 24.6 kcaymol as a consequence of n-delocalization (eq 1).* In this paper, the effect of substituents in controlling the nonplanarity of B&-H)sH3+ (lb) is discussed. Subramanian School of Chemistry, University of Hyderabad, Hyderabad 500 046, India Received JIsoelectronic borocyclic analogs of cyclopropenyl cation,' B3H32- (I), (11), and (111), have been predicted to be planar 2 n Huckel aromatic^.^-^ However, the A H H II Ill 20, D 3 h, 90.6 (3) Li 2.193 1.330 2.182 / cationic species (la) with a planar structure was characterized to be a transition The nonplanar C3v symmetric structure l b was predicted to be the minimum.
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