Chemical and electrochemical formation of pseudorotaxanes composed of alkyl(ferrocenylmethyl)ammmonium and dibenzo[24]crown-8
Chemical and electrochemical formation of pseudorotaxanes composed of alkyl(ferrocenylmethyl)ammmonium and dibenzo[24]crown-8
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DOI：
10.1021/ic050215f
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发表时间：
2005-08-08
影响因子：
4.6
通讯作者：
Osakada, K
中科院分区：
文献类型：
--
作者：
Horie, M;Suzaki, Y;Osakada, K
对二甲苯氨基甲基二茂铁 (1) 和正己基氨基甲基二茂铁 (2) 通过 HCl 和 NH(4)PF(6) 质子化，形成二茂铁基甲基（烷基）铵盐。通过二苯并[24]冠-8 (DB24C8) 包合这些化合物分别产生 12] 拟轮烷，[(DB24C8)(1-H)](+)(PF(6)) 和 [(DB24C8)(2-H)]+(PF(6))。前一产物的X射线衍射显示出由轴和大环分子组成的互锁结构。观察到分子间 N-H(...)O 和 C-H(...)O 相互作用以及芳香族平面的堆积。固态[(DB24C8)(1-H)]+(PF6) 通过红外光谱和元素分析进行表征。 1,1'-双(对二甲苯氨基甲基)二茂铁 (3) 的类似反应形成 [2] 和 [3] 拟轮烷的混合物，[(DB24C6)(3-H(2))(2+)(PF6)2 和 [(DB24C8)(2)(3-H(2))](2+)(PF(6))(2)。后一种具有两个 DB24C8 分子的产物被分离并通过 X 射线晶体学表征。 (1)H NMR 和质谱证实了这些拟轮烷在 CD(3)CN 溶液中的形成。在 TEMPOH（1-羟基-2,2,6,6-四甲基哌啶）和 DB24C8 存在下，1-3 在 0.4 V（相对于 Ag(+)/Ag）下进行电化学氧化，得到相应的拟轮烷。反应混合物的 ESR 光谱表明以高产率形成了 TEMPO 自由基。通过使用与光谱测量相关的流动电解方法研究配体的二烷基氨基转化为二烷基铵基团的细节。所提出的反应机制涉及通过初始氧化形成的二茂铁物种，其经历从氮到Fe(III)中心的电子转移，在氮处产生阳离子自由基，氢从TEMPOH转移到阳离子自由基，并通过DB24C8包含所得二烷基铵物种产生拟轮烷。
Protonation of p-xylylaminomethylferrocene (1) and n-hexylaminomethylferrocene (2) by HCl and NH(4)PF(6) forms the ferrocenylmethyl(alkyl)ammonium salt. Inclusion of the compounds by dibenzo[24]crown-8 (DB24C8) produces 12]pseudorotaxanes, [(DB24C8)(1-H)](+)(PF(6)) and [(DB24C8)(2-H)]+(PF(6)), respectively. X-ray diffraction of the former product indicates an interlocked structure composed of the axis and the macrocyclic molecule. Intermolecular N-H(...)O and C-H(...)O interactions and stacking of the aromatic planes are observed. [(DB24C8)(1-H)]+(PF6), in the solid state, is characterized by IR spectroscopy and elemental analyses. A similar reaction of 1,1'-bis(p-xylylaminomethyl)ferrocene (3) forms a mixture of [2] and [3]pseudorotaxanes, [(DB24C6)(3-H(2))(2+)(PF6)2 and [(DB24C8)(2)(3-H(2))](2+)(PF(6))(2). The latter product having two DB24C8 molecules is isolated and characterized by X-ray crystallography. Formation of these pseudorotaxanes in a CD(3)CN solution is evidenced by (1)H NMR and mass spectrometry. Electrochemical oxidation of 1-3 at 0.4 V (vs Ag(+)/Ag) in the presence of TEMPOH (1-hydroxy-2,2,6,6 -tetramethylpiperidine) and DB24C8 affords the corresponding pseudorotaxanes. The ESR spectrum of the reaction mixture indicates the formation of a TEMPO radical in high yield. Details of the conversion of the dialkylamino group of the ligand to the dialkylammonium group are investigated by using a flow electrolysis method linked to spectroscopic measurements. The proposed mechanism for the reaction involves the ferrocenium species, formed by initial oxidation, which undergoes electron transfer from nitrogen to the Fe(III) center, producing a cation radical at the nitrogen, Transfer of hydrogen from TEMPOH to the cation radical and inclusion of the resulting dialkylammonium species by DB24C8 yields the pseudorotaxanes.