Liu Na, Li Qingzhong, Scheiner Steve, Xie Xiaoying
The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, P. R. China.
Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA.
Phys Chem Chem Phys. 2022 Jun 22;24(24):15015-15024. doi: 10.1039/d2cp01244h.
The possibility that the intramolecular Tr⋯S triel bond is strengthened by resonance is examined by quantum chemical calculations within the planar five-membered ring of TrH-CRCR-CRS (Tr = Al, Ga, In; R = NO, CH). This internal bond is found to be rather short (2.4-2.7 Å) with a large bond energy between 12 and 21 kcal mol. The pattern of bond length alternation and atomic charges within the ring is consistent with resonance involving the conjugated double bonds. This resonance enhances the triel bond strength by some 25%. The electron-withdrawing NO group weakens the bond, but it is strengthened by the electron-donating CH substituent. NICS analysis suggests the presence of a certain degree of aromaticity within the ring.
通过量子化学计算，在TrH-CRCR-CRS（Tr = Al、Ga、In；R = NO、CH）的平面五元环内研究了分子内Tr⋯S三中心键通过共振得以加强的可能性。发现这种内键相当短（2.4 - 2.7 Å），键能在12至21千卡/摩尔之间。环内键长交替和原子电荷模式与涉及共轭双键的共振一致。这种共振使三中心键强度提高了约25%。吸电子的NO基团会削弱该键，但给电子的CH取代基会加强该键。NICS分析表明环内存在一定程度的芳香性。
