School of Applied Sciences and Humanities, Haldia Institute of Technology, Haldia, 721657, India.
Phys Chem Chem Phys. 2019 Nov 14;21(42):23301-23304. doi: 10.1039/c9cp04361f. Epub 2019 Sep 6.
Boron compounds usually exhibit Lewis acidity at the boron center due to the presence of vacant p-orbitals. We show that this chemistry can be altered by an appropriate choice of ligands to decorate the boron center. To elucidate this effect, we studied the interactions of boron with two classes of ligands, one based on penta-substituted phenyl species (CX, X = F, BO, CN) and the other based on Zintl-ion-based groups (GeY, Y = H, CH, BO, CN). An in-depth analysis of the charges and Fukui function values at the local atomic sites of the substituted boron derivatives B(CX) and B[GeY] shows that the B-center in the former is electrophilic, while it is nucleophilic in the latter. The chemical stability of the B[GeY] species is shown to be due to the presence of strong 2c-2e bonds between the B and Ge centers. Thus, the general notion of the Lewis acid nature of a boron center depends upon the choice of the ligand.
硼化合物通常由于空的 p 轨道的存在而在硼中心表现出路易斯酸性。我们表明，通过选择适当的配体来修饰硼中心，可以改变这种化学性质。为了阐明这种效应，我们研究了硼与两类配体的相互作用，一类基于五取代的苯基物种（CX，X = F、BO、CN），另一类基于 Zintl 离子基基团（GeY，Y = H、CH、BO、CN）。对取代硼衍生物 B(CX) 和 B[GeY] 的局部原子位点的电荷和 Fukui 函数值进行深入分析表明，前者的 B 中心是亲电性的，而后者的 B 中心是亲核性的。B[GeY] 物种的化学稳定性归因于 B 和 Ge 中心之间存在强的 2c-2e 键。因此，硼中心路易斯酸性的一般概念取决于配体的选择。
