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Diboron Bonds Between BX 3 (X=H, F, CH 3 ) and BYZ 2 (Y=H, F; Z=CO, N 2 , CNH)
Author(s) -
Yang Qingqing,
Li Qingzhong,
Scheiner Steve
Publication year - 2021
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202100332
Subject(s) - chemistry , non covalent interactions , covalent bond , crystallography , molecule , single bond , stereochemistry , chemical bond , formal charge , atom (system on chip) , ab initio , hydrogen bond , alkyl , organic chemistry , computer science , embedded system
The ability of B atoms on two different molecules to engage with one another in a noncovalent diboron bond is studied by ab initio calculations. Due to electron donation from its substituents, the trivalent B atom of BYZ 2 (Z=CO, N 2 , and CNH; Y=H and F) has the ability to in turn donate charge to the B of a BX 3 molecule (X=H, F, and CH 3 ), thus forming a B⋅⋅⋅B diboron bond. These bonds are of two different strengths and character. BH(CO) 2 and BH(CNH) 2 , and their fluorosubstituted analogues BF(CO) 2 and BF(CNH) 2 , engage in a typical noncovalent bond with B(CH 3 ) 3 and BF 3 , with interaction energies in the 3–8 kcal/mol range. Certain other combinations result in a much stronger diboron bond, in the 26–44 kcal/mol range, and with a high degree of covalent character. Bonds of this type occur when BH 3 is added to BH(CO) 2 , BH(CNH) 2 , BH(N 2 ) 2 , and BF(CO) 2 , or in the complexes of BH(N 2 ) 2 with B(CH 3 ) 3 and BF 3 . The weaker noncovalent bonds are held together by roughly equal electrostatic and dispersion components, complemented by smaller polarization energy, while polarization is primarily responsible for the stronger ones.