Synthetic, Cyclovoltammetric, and UV-Photoelectron Spectroscopic Studies of 2,3-Dihydro-1H-1,3,2-diazaboroles and 1,3,2-Diazaborolidines

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• 作者：Lothar Weber ; Imme Domke ; Wilko Greschner ; Karinne Miqueu ; Anna Chrostowska ; and Patrick Bayl&egrave ; re
• 刊名：Organometallics
• 出版年：2005
• 出版时间：October 24, 2005
• 年：2005
• 卷：24
• 期：22
• 页码：5455 - 5463
• 全文大小：237K
• 年卷期：v.24,no.22(October 24, 2005)
• ISSN：1520-6041

文摘

The oxidation potentials E_ox of a series of 2,3-dihydro-1H-1,3,2-diazaboroles^tBuNCH=CHN(^tBu)BR (1a-i) and of the corresponding saturated 1,3,2-diazaborolidines 2a(R = NH₂), 2b (OMe), 2c (Me), 2d (NMe₂), 2e (H), 2f (SMe), 2g (SnMe₃), 2h (Br), 2i (CN)were determined by cyclovoltammetry in CH₂Cl₂ solution. The potentials E_ox of theirreversible electrochemical oxidations range from E_ox = -288 mV (1a) to 752 mV (1i). Incontrast to this, E_ox of the corresponding diazaborolidines are anodically shifted by 260 mV(1d, 2d) to 752 mV (1b, 2b) and vary from 280 mV (2a) to 1164 mV (2i). Gas-phasephotoelectron spectra of representatives of both series of compounds were recorded andassessed by density functional calculations. The first ionization potentials of the 2,3-dihydro-1H-1,3,2-diazaboroles range in the series 1c (7.1 eV) < 1f (7.3 eV) < 1e = 1h (7.4 eV) < 1i(7.7 eV). They differ by less than 0.3 eV from the first ionization potentials determined forthe saturated analogues [1st IP for 2c (7.3 eV) < 2e = 2f (7.4 eV) < 2h (7.7 eV)].