Different Nature of the Interactions between Anions and HAT(CN)6: From Reversible Anion-π Complexes to Irreversible Electron-Transfer Processes (HAT(CN)6=1,45,819,12-Hexaazatriphenylene)
Different Nature of the Interactions between Anions and HAT(CN)6: From Reversible Anion-π Complexes to Irreversible Electron-Transfer Processes (HAT(CN)6=1,45,819,12-Hexaazatriphenylene)
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DOI：
10.1021/ja309960m
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发表时间：
2013-02-20
影响因子：
15
通讯作者：
Ballester, Pablo
中科院分区：
文献类型：
--
作者：
Aragay, Gemma;Frontera, Antonio;Ballester, Pablo
我们报道了实验证据表明，HAT（CN）（6），一种众所周知的强电子受体芳香族化合物，与单原子或多原子阴离子之间建立的相互作用的性质从几乎完全形成可逆的阴离子-稀土络合物转变，具有明显的电荷转移（CT）或形式电子转移（ET）特征，与阴离子自由基[HAT（CN）（6）]（中心点-）和二价阴离子[HAT（CN）（6）]（2-）物质的定量和不可逆净产生有关。优选的相互作用模式由相互作用阴离子的电子供体能力决定。因此，较弱的刘易斯碱性阴离子如Br-或I-倾向于主要形成阴离子-π络合物。相反，强刘易斯碱性F-或-OH阴离子显示净ET过程。ET过程可以是热诱导的或光诱导的，这取决于电子供体（阴离子）和电子受体（HAT（CN）（6））之间的HOMO/LUMO能量差。这些ET过程可能涉及阴离子-π络合物的中间性，具有强ET特征并产生离子对自由基络合物。我们假设，形成溶剂笼状复合物的对自由基的不可逆解离是由阴离子产生的自由基的稳定性降低（高反应性）引起的。
We report experimental evidence indicating that the nature of the interaction established between HAT(CN)(6), a well-known strong electron acceptor aromatic compound, with mono- or polyatomic anions switches from the almost exclusive formation of reversible anion-re complexes, featuring a markedly charge transfer (CT) or formal electron-transfer (ET) character, to the quantitative and irreversible net production of the anion radical [HAT(CN)(6)](center dot-) and the dianion [HAT(CN)(6)](2-) species. The preferred mode of interaction is dictated by the electron donor abilities of the interacting anion. Thus, weaker Lewis basic anions such as Br- or I- are prone to form mainly anion-pi complexes. On the contrary, stronger Lewis basic F- or -OH anions display a net ET process. The ET process can be either thermal or photoinduced depending on the HOMO/LUMO energy difference between the electron donor (anion) and the electron acceptor (HAT(CN)(6)). These ET processes possibly involve the intermediacy of anion-pi complexes having strong ET character and producing an ion-pair radical complex. We hypothesize that the irreversible dissociation of the pair of radicals forming the solvent-caged complex is caused by the reduced stability (high reactivity) of the radical resulting from the anion.