Electronic and structural properties of N → B-ladder boranes with high electron affinity
Electronic and structural properties of N → B-ladder boranes with high electron affinity
复制标题
DOI：
10.1039/c7qo00876g
复制
发表时间：
2018-02-07
影响因子：
5.4
通讯作者：
Pammer, Frank
中科院分区：
文献类型：
--
作者：
Grandl, Markus;Sun, Yu;Pammer, Frank
通过双官能团四元吡啶、嘧啶和1，5-萘啶前体与9 H-BBN和Piers硼烷（（C6 F5）（2）BH）的二次硼氢化反应，高产率地合成了一系列新的π共轭N -> B-梯形硼烷。几个梯形硼烷的结构已被证实的X-射线晶体学，其光学和电化学性质已被表征，并通过DFT计算补充。个别梯形硼烷的电子结构，以及源自硼基侧链的化学结构的光学性质的差异，进行了讨论。结果一致地表明，与前体相比，梯形硼烷的光学带隙显著减小，并且电子亲合势强烈增加至-3.4至-4.0 eV。化学和电化学还原物种的进一步调查表明，在这些种类的系统中的过量电子有效地离域整个共轭系统。
A series of new pi-conjugated N -> B-ladder boranes has been prepared in high yield by two-fold hydroboration of bifunctional quaterpyridine-, pyrimidine-, and 1,5-naphthyridine-based precursors with 9H-BBN and Piers' borane ((C6F5)(2)BH). The structures of several ladder-boranes have been confirmed by X-ray crystallography, and their optical and electrochemical properties have been characterized, and complemented by DFT calculations. The electronic structure of the individual ladder boranes, as well as differences in the optical properties that originate from the chemical structure of the boryl-side-chains, are discussed. The results consistently show that, compared to the precursors, the optical gaps of the ladder boranes are significantly reduced, and the electron affinities are strongly increased to between -3.4 and -4.0 eV. Further investigations of chemically and electrochemically reduced species indicate that excess electrons in these kinds of systems are effectively delocalized throughout the conjugated systems.