Synthesis and characterization of compounds with boron-boron double bonds
作者:Philip P. Power
DOI:10.1016/s0020-1693(00)92388-0
日期:1992.8
non-planar precursors) consistent with the formation of a π-bond between the boron centers. Their 11 B NMR spectra display peaks that are shifted upfield relative to the starting compounds. In the case of the amido derivative, two B-N π-bonds were cleaved in the reduction process. The electronic absorption spectrum of this compound in Et 2 O displays an intense absorption at 320 nm which may be attributed
摘要乙硼烷(4)衍生物Mes 2 BB(Mes)Ph和Me 2 N(Ph)BB(Ph)NMe 2易于与锂粉在乙醚中反应,生成双还原的盐[(Et 2 O)Li} 2 Mes 2 BB(Mes)Ph]和[(Et 2 O)Li} 2 Me 2 N(Ph)BB(Ph)NMe 2]。两种物质都被分离为红色晶体,已通过X射线晶体学,11 B NMR和电子光谱进行了表征。结构数据表明,与地层一致的B planar-B距离接近1.63 A的平面或几乎平面的B 2 C 4或B 2 C 2 N 2核(比照中性非平面前体的B nearB = 1.71 A)硼中心之间的π键。他们的11 B NMR谱图显示了相对于起始化合物向高场偏移的峰。在酰胺衍生物的情况下,在还原过程中裂解了两个BNπ键。该化合物在Et 2 O中的电子吸收光谱在320 nm处显示出强烈的吸收,这可能归因于BBπ键的π-π*跃迁。这表明该键的强度约为40kcal