Bishop Sophie, Tremblay Marie-Hélène, Gellé Alexandra, Skene W G
Laboratoire de caractérisation photophysique des matériaux conjugués, Département de Chimie , Université de Montréal , CP 6128 Centre-ville , Montreal , Quebec.
J Phys Chem A. 2019 Apr 4;123(13):2687-2693. doi: 10.1021/acs.jpca.8b10593. Epub 2019 Mar 20.
With the aim of achieving reversible oxidation and color tuning, the effect of the central aromatic on the spectroscopic, electrochemical, and spectrochemical properties of a series of electrochromic azomethine triads was investigated. The absorption of the alkylated thiophene derivatives was blue-shifted relative to their unalkylated counterparts when the central aromatic was either a bi- or terthiophene. It was further found that the alkylated thiophene derivatives had larger Stokes shifts than their unsubstituted counterparts. Theoretical calculations demonstrated that the torsion angles of these alkylated cores with respect to the flanking azomethines were responsible for the spectroscopic effects. While the electrochemical oxidation potential of the triads varied by only 100 mV, the reversibility of their anodic process was contingent on the central aromatic. The absorption of the electrochemically produced state red-shifted between 165 and 280 nm from its corresponding neutral state, leading to perceived color changes between orange and blue. Reversible color changes were chemically mediated with ferric chloride/hydrazine. The absorption of the chemically oxidized state shifted between 155 and 220 nm from the corresponding neutral state, contingent on the central aromatic. The palette of perceived colors that was possible with oxidation included orange, yellow, blue, and gray.
为了实现可逆氧化和颜色调节，研究了中心芳烃对一系列电致变色偶氮甲碱三联体的光谱、电化学和光谱化学性质的影响。当中心芳烃为联噻吩或三联噻吩时，烷基化噻吩衍生物的吸收相对于未烷基化的对应物发生蓝移。进一步发现，烷基化噻吩衍生物的斯托克斯位移比未取代的对应物更大。理论计算表明，这些烷基化核心相对于侧翼偶氮甲碱的扭转角是造成光谱效应的原因。虽然三联体的电化学氧化电位仅变化100 mV，但其阳极过程的可逆性取决于中心芳烃。电化学产生状态的吸收相对于其相应的中性状态在165至280 nm之间发生红移，导致在橙色和蓝色之间观察到颜色变化。用氯化铁/肼进行化学介导实现了可逆颜色变化。化学氧化状态的吸收相对于相应的中性状态在155至220 nm之间移动，这取决于中心芳烃。氧化时可能出现的颜色范围包括橙色、黄色、蓝色和灰色。
