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Lowering the Reduction Potential of a Boron Compound by Means of the Substituent Effect of the Boryl Group: One‐Electron Reduction of an Unsymmetrical Diborane(4) |
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| Authors: | Hiroki Asakawa Ka‐Ho Lee Prof?Dr Ko Furukawa Prof?Dr Zhenyang Lin Prof?Dr Makoto Yamashita |
| Institution: | 1. Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1‐13‐27, Kasuga, Bunkyo‐ku, 112‐8551 Tokyo (Japan) http://www.chem.chuo‐u.ac.jp/～element/index‐e.html;2. Department of Chemistry, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon (Hong Kong);3. Center for Instrumental Analysis, Institute for Research Promotion, Niigata University, 8050 Ikarashi 2‐no‐cho, Nishi‐ku, Niigata 950‐2181 (Japan) |
| Abstract: | We have clarified and observed the high electron affinity of pinB?BMes2 ( 1 ; Mes=mesityl, pin=pinacolato). By using electrochemistry, it was shown that 1 has a higher electron affinity than those of B2pin2 and Mes3B. One‐electron reduction of 1 gave the corresponding radical anion. The ESR spectroscopy and DFT calculation revealed the unsymmetrical distribution of electron density over the B?B bond. UV/Vis spectroscopy showed that the SOMO‐related absorption supports the deep purple color of the radical anion. DFT studies on the torsion angle dependency of the LUMO levels and relative energies revealed the reason why 1 has high electron affinity as a result of the substituent effect of the Bpin group. |
| Keywords: | boranes density functional calculations radical anions substituent effect torsion angles |