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Nature and Strength of Lewis Acid/Base Interaction in Boron and Nitrogen Trihalides
Author(s) -
Rodrigues Silva Daniela,
Azevedo Santos Lucas,
Freitas Matheus P.,
Guerra Célia Fonseca,
Hamlin Trevor A.
Publication year - 2020
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.202001127
Subject(s) - lewis acids and bases , adduct , boron , frustrated lewis pair , chemistry , acceptor , molecule , crystallography , computational chemistry , nitrogen , bond strength , stereochemistry , organic chemistry , catalysis , physics , adhesive , condensed matter physics , layer (electronics)
We have quantum chemically investigated the bonding between archetypical Lewis acids and bases. Our state‐of‐the‐art computations on the X 3 B−NY 3 Lewis pairs have revealed the origin behind the systematic increase in B−N bond strength as X and Y are varied from F to Cl, Br, I, H. For H 3 B−NY 3 , the bonding trend is driven by the commonly accepted mechanism of donor−acceptor [HOMO(base)−LUMO(acid)] interaction. Interestingly, for X 3 B−NH 3 , the bonding mechanism is determined by the energy required to deform the BX 3 to the pyramidal geometry it adopts in the adduct. Thus, Lewis acids that can more easily pyramidalize form stronger bonds with Lewis bases. The decrease in the strain energy of pyramidalization on going from BF 3 to BI 3 is directly caused by the weakening of the B−X bond strength, which stems primarily from the bonding in the plane of the molecule (σ‐like) and not in the π system, at variance with the currently accepted mechanism.