Institute of Inorganic Chemistry of the Czech Academy of Sciences, Husinec, Řež 250 68, Czech Republic.
Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K.
Inorg Chem. 2020 Mar 2;59(5):2651-2654. doi: 10.1021/acs.inorgchem.0c00179. Epub 2020 Feb 11.
Methylation of -BH () affords the first example of alkyl substitution of terminal hydrogen atoms on the fluorescent octadecaborane-22 molecule to give highly methylated 2,2'-Cl-1,1',3,3',4,4',7,7',8,8',10,10'-Me--BH (). This extensive chemical substitution leads to a swelling in the polyhedral volume of the 18-vertex boron atomic skeleton of the molecule and an enhancement of the absorption and solubility characteristics of this highly fluorescent molecule. We propose this "swollen polyhedral volume" to be the result of a marked increase in the relative positivity of the "cluster-only total charge" of the boron atomic skeleton caused by the combined electron-withdrawing capacity of the 12 methyl groups. Enhancement in the absorption and solubility properties may be crucial in the design of new borane-based laser materials.
甲基化- BH () 提供了第一个例子，即末端氢原子在荧光十八硼烷-22 分子上的烷基取代，得到高度甲基化的 2,2'-Cl-1,1',3,3',4,4',7,7',8,8',10,10'-Me--BH ()。这种广泛的化学取代导致分子中 18 个顶点硼原子骨架的多面体体积膨胀，并增强了这种高荧光分子的吸收和溶解度特性。我们提出这种“膨胀的多面体体积”是由于硼原子骨架的“仅簇总电荷”的相对正性显著增加的结果，这是由于 12 个甲基的组合电子受电子能力引起的。吸收和溶解度特性的增强可能在新型硼烷基激光材料的设计中至关重要。
