Four-electron Oxidative Dehydrogenation Induced by Proton-Coupled Electron Transfer in Ruthenium Complex with 2-(1,3,4,5-Tetrhydropyrimidine-2-yl) phenolate
Four-electron Oxidative Dehydrogenation Induced by Proton-Coupled Electron Transfer in Ruthenium Complex with 2-(1,3,4,5-Tetrhydropyrimidine-2-yl) phenolate
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2-(1,3,4,5-四氢嘧啶-2-基)酚盐钌配合物中质子耦合电子转移诱导的四电子氧化脱氢
DOI：
10.1021/ic401667v
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发表时间：
2013
影响因子：
4.6
通讯作者：
Yukinari Sunatsuki
中科院分区：
文献类型：
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作者：
Ryoji Mitsuhashi;Takayoshi Suzuki;Yukinari Sunatsuki
合成了通式为[Ru（O-N）（bpy）2]n+（O-N =不对称双齿酚盐配体; bpy = 2，2 ′-联吡啶）的钌（II或III）配合物，并对其晶体结构和电化学性质进行了表征。 钌与2-（2-咪唑啉基）苯酚（Himn-）或2-（1，4，5，6-四氢嘧啶-2-基）苯酚（Hthp-）的配合物可通过加入过量的KOtBu而被去质子化，尽管去质子化的物种在暴露于空气中时容易被再质子化。与这些Ru II络合物不同，它们的Ru III类似物在加入碱后显示出有趣的配体氧化反应。在[RuIII（Himn）（bpy）2]2+存在下，Himn-的双电子氧化和RuIII中心的还原导致2-咪唑啉基转化为2-咪唑基。另一方面，相应的Hthp-配合物表现出配体的四电子氧化，形成2-（2-嘧啶基）苯酚盐（pym-）。咪唑啉基和1，4，5，6-四氢嘧啶基的芳构化反应也通过电化学生成的RuIII络合物实现。
New ruthenium(II or III) complexes with general formula [Ru(O-N)(bpy)2]n+(O-N = unsymmetrical bidentate phenolate ligand; bpy = 2,2′-bipyridine) were synthesized, and their crystal structures and electrochemical properties were characterized. RuIIcomplexes with 2-(2-imidazolinyl)phenolate (Himn–) or 2-(1,4,5,6-tetrahydropyrimidin-2-yl)phenolate (Hthp–) could be deprotonated by addition of excess KOtBu, although the deprotonated species were easily reprotonated by exposure to air. Unlike these RuIIcomplexes, their RuIIIanalogs showed interesting ligand oxidation reactions upon addition of bases. With [RuIII(Himn)(bpy)2]2+, two-electron oxidation of Himn–and reduction of the RuIIIcenter resulted in conversion of the 2-imidazolinyl group to a 2-imidazolyl group. On the other hand, the corresponding Hthp–complex exhibited four-electron oxidation of the ligand to form 2-(2-pyrimidyl)phenolate (pym–). These aromatization reactions of imidazolinyl and 1,4,5,6-tetrahydropyrimidyl groups were also achieved by the electrochemically generated RuIIIcomplexes.