Michalczyk Mariusz, Zierkiewicz Wiktor, Scheiner Steve
Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
Department of Chemistry and Biochemistry, Utah State University Logan, Utah, 84322-0300, United States.
Chemphyschem. 2018 Nov 19;19(22):3122-3133. doi: 10.1002/cphc.201800774. Epub 2018 Oct 10.
Complexes between TrR (Tr=B, Al, Ga; R=H, F, Cl, Br, CH ) molecules and pyrazine have been characterized at the MP2 and CCSD(T) levels of theory. The adducts can be grouped according to the type of molecular arrangement. The first situation places the Tr atom in the plane of the pyrazine ring and contains a triel bond to the N lone pair. For the boron complexes the orbital interaction energy is almost equal to the electrostatic component, while the former is only half the latter for Tr=Al and Ga. The two monomers are stacked above one another in the second configuration, which depends to a greater degree upon orbital interaction and dispersion. The former complexes are more strongly bonded than the latter. Interaction energies (E ) for the stronger complexes vary between -50 and -20 kcal/mol for BBr and Ga(CH ) paired respectively with pyrazine. E is much smaller for the stacked configurations, ranging from -8 for GaF to -1.4 kcal/mol for BF . The value of the maximum of the electrostatic potential correlates poorly with E , attributed in part to monomer distortions upon complexation.
已在MP2和CCSD(T)理论水平上对TrR（Tr = B、Al、Ga；R = H、F、Cl、Br、CH ）分子与吡嗪之间的配合物进行了表征。加合物可根据分子排列类型进行分组。第一种情况是将Tr原子置于吡嗪环平面内，并包含一个与N孤对的三价元素键。对于硼配合物，轨道相互作用能几乎等于静电成分，而对于Tr = Al和Ga，前者仅为后者的一半。在第二种构型中，两个单体相互堆叠，这种构型在更大程度上取决于轨道相互作用和色散。前者的配合物比后者的键合更强。对于分别与吡嗪配对的BBr和Ga(CH )，较强配合物的相互作用能（E ）在-50至-20 kcal/mol之间变化。对于堆叠构型，E要小得多，范围从GaF的-8到BF 的-1.4 kcal/mol。静电势最大值与E 的相关性很差，部分原因是络合时单体发生了畸变。
