Wu Boning, Liang Min, Maroncelli Mark, Castner Edward W
Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey , 610 Taylor Road, Piscataway, New Jersey 08854, United States.
Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
J Phys Chem B. 2015 Nov 19;119(46):14790-9. doi: 10.1021/acs.jpcb.5b09216. Epub 2015 Nov 9.
Ionic liquids with electron-donating anions are used to investigate rates and mechanisms of photoinduced bimolecular electron transfer to the photoexcited acceptor 9,10-dicyanoanthracene (9,10-DCNA). The set of five cyano anion ILs studied comprises the 1-ethyl-3-methylimidazolium cation paired with each of these five anions: selenocyanate, thiocyanate, dicyanamide, tricyanomethanide, and tetracyanoborate. Measurements with these anions dilute in acetonitrile and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide show that the selenocyanate and tricyanomethanide anions are strong quenchers of the 9,10-DCNA fluorescence, thiocyanate is a moderately strong quencher, dicyanamide is a weak quencher, and no quenching is observed for tetracyanoborate. Quenching rates are obtained from both time-resolved fluorescence transients and time-integrated spectra. Application of a Smoluchowski diffusion-and-reaction model showed that the complex kinetics observed can be fit using only two adjustable parameters, D and V0, where D is the relative diffusion coefficient between donor and acceptor and V0 is the value of the electronic coupling at donor-acceptor contact.
具有供电子阴离子的离子液体用于研究光致双分子电子转移至光激发受体9,10-二氰基蒽（9,10-DCNA）的速率和机理。所研究的一组五种氰基阴离子离子液体包含1-乙基-3-甲基咪唑阳离子与以下五种阴离子中的每一种配对：硒氰酸盐、硫氰酸盐、双氰胺、三氰甲烷化物和四氰硼酸盐。在乙腈和1-乙基-3-甲基咪唑双（三氟甲基磺酰）酰胺中稀释这些阴离子进行测量表明，硒氰酸盐和三氰甲烷化物阴离子是9,10-DCNA荧光的强猝灭剂，硫氰酸盐是中等强度的猝灭剂，双氰胺是弱猝灭剂，而对于四氰硼酸盐未观察到猝灭现象。猝灭速率可从时间分辨荧光瞬态和时间积分光谱获得。应用Smoluchowski扩散-反应模型表明，观察到的复杂动力学仅使用两个可调参数D和V0即可拟合，其中D是供体和受体之间的相对扩散系数，V0是供体-受体接触时的电子耦合值。
