Yang Qingqing, Chi Zongqing, Li Qingzhong, Scheiner Steve
The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China.
Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA.
J Chem Phys. 2020 Aug 21;153(7):074304. doi: 10.1063/5.0018950.
The ability of the F atom of HC≡CF, HC=CHF and HCCHF to serve as an electron donor to the triel (Tr) atom of TrR in the context of a triel bond is assessed by ab initio calculations. The triel bond formed by C-F is strongest, as high as 30 kcal/mol, followed by C-F, and then by C-F whose triel bonds can be as small as 1 kcal/mol. The noncovalent bond strength diminishes in the order Tr = Al > Ga > B, consistent with the intensity of the π-hole above the Tr atom in the monomer. The triel bond strength of the Al and Ga complexes increases along with the electronegativity of the R substituent but is largest for R=H when Tr=B. Electrostatics play the largest role in the stronger triel bonds, but dispersion makes an outsized contribution for the weakest such bonds.
通过从头算计算评估了在三卤键的背景下，HC≡CF、HC=CHF和HCCHF中的F原子作为电子供体与TrR中的三卤（Tr）原子形成三卤键的能力。由C-F形成的三卤键最强，高达30千卡/摩尔，其次是C-F，然后是C-F，其形成的三卤键小至1千卡/摩尔。非共价键强度按Tr = Al > Ga > B的顺序递减，这与单体中Tr原子上方π空穴的强度一致。Al和Ga配合物的三卤键强度随着R取代基的电负性增加而增加，但当Tr = B时，R = H时三卤键强度最大。在较强的三卤键中，静电作用起最大作用，但对于最弱的此类键，色散作用贡献巨大。
