Diboron Bonds Between BX₃ (X=H, F, CH₃) and BYZ₂ (Y=H, F; Z=CO, N₂, CNH)

Abstract

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.

Quantum‐Rod On‐Chip LEDs for Display Backlights with Efficacy of 149 lm W−1: A Step toward 200 lm W−1

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“…[ 29 ] Thus, for the on‐chip application, we need to improve the thermal and optical stability of the QRs with a large absorption cross‐section. The thermal quenching of quantum materials can be explained by the thermally activated physical process, [ 30 ] including electron resonance tunneling into pre‐existing surface trap states, injection over the barrier energy back to the core, and recombines with the confined holes. Recently, numerous research papers are published focusing on the structural optimization of core–shell nanocrystals to improve photochemical and thermal stability.…”

“…[ 26 ] Recently, Zhong's group revealed the highest stability that Cd x Zn 1− x Se y S 1− y @ZnS of ZnSe rich QDs with multi outer ZnS shell retaining 85.1% of QY at 500 K in vacuum. [ 30 ]…”

Catalytic Kinetic Resolution and Desymmetrization of Amines

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Triel bonds within anion···anion complexes

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