Intermolecular Hydrogen Bonds between a Radical and a Diamagnetic Matrix: CW-ESR Investigations of 2,6-Di-<i>tert</i>-butyl-4-hydroxymethylphenol
作者:Toshiki Yamaji、Islam SM Saiful、Masaaki Baba、Seigo Yamauchi、Jun Yamauchi
DOI:10.1246/bcsj.82.58
日期:2009.1.15
We propose a novel formation model of an intermolecular hydrogen bond between radicals and a diamagnetic matrix in the condensed phase. W-band and multi-frequency ESR studies revealed that the polycrystalline radical sample generated from PbO2 oxidation of 2,6-di-tert-butyl-4-hydroxymethylphenol in toluene solution in vacuum at room temperature has an anomalously large 1H-hyperfine interaction. It was concluded that this interaction is attributed to hydrogen bonding between thepara-OH or the phenolic OH of the primary phenol. Although the phenol shows interesting radical chemical reactions unlike other 2,6-di-tert-butylphenol derivatives, the generated radical species were successfully defined by the solution ESR investigations. This may be the first ESR observation of an anomalously large hyperfine doublet structure coming from a proton on an intermolecular hydrogen bond between a radical and a diamagnetic phenol.which is a paramagnetic center in the molecular structure of the radicals and the
我们提出了一种新的形成模型,即凝聚相中自由基与二磁性基体之间的分子间氢键。W 波段和多频 ESR 研究表明,在室温真空中,PbO2 氧化甲苯溶液中的 2,6- 二叔丁基-4-羟甲基苯酚所生成的多晶自由基样品具有异常大的 1H 超精细相互作用。得出的结论是,这种相互作用归因于初级苯酚的para-OH 或酚羟基之间的氢键。尽管与其他 2,6- 二叔丁基苯酚衍生物不同,该苯酚显示出有趣的自由基化学反应,但溶液 ESR 研究成功地确定了生成的自由基种类。这可能是首次通过 ESR 观察到异常大的超频双特结构,它来自自由基与二磁性苯酚之间分子间氢键上的质子。