Indirect Nuclear Spin-Spin Coupling Constants <sup>1</sup>J(<sup>17</sup>O,<sup>11</sup>B). First Observation And Calculation Using Density Functional Theory (Dft)
作者:Bernd Wrackmeyer、Oleg L. Tok
DOI:10.1515/znb-2006-0804
日期:2006.8.1
Coupling constants 1J(17O,11B) of borates, borane adducts and boranes with boron-oxygen bonds have been calculated on the basis of optimised molecular structures using the B3LYP/6-311+G(d,p) level of theory. This indicates that such coupling constants can be of either sign and that their magnitudes can be rather small. Since both 11B and 17O are quadrupole nuclei, it is therefore difficult to measure
已使用 B3LYP/6-311+G(d,p) 理论水平在优化分子结构的基础上计算了硼酸盐、硼烷加合物和硼烷的偶联常数 1J(17O,11B)。这表明这种耦合常数可以是任一符号,并且它们的大小可以相当小。由于 11B 和 17O 都是四极原子核,因此很难测量有代表性的数据。在三甲氧基硼烷和四乙基二硼烷的情况下,通过在高温(120°C 和 160°C)下测量 17O NMR 光谱,证明可以分别获得实验数据 1J(17O,11B)(22 和 18 Hz)。这些耦合常数的大小与计算数据合理一致。在二硼烷的情况下,这指向键角 BOB 更接近 180°而不是 140°