Substituent and solvent effects on the fluorescent and photochromic properties of 2-(2-pyridyl)imidazole containing diarylethene derivatives
作者:Xuefeng Peng、Jian-Guo Deng、Hai-Bing Xu
DOI:10.1039/c3ra43110j
日期:——
Five diarylethene derivatives with 2-(2-pyridyl)imidazole as the ethene bridges (PI-BTEs) were synthesized and characterized. The structures and performances of the PI-BTEs (L1–L5) could be modified from not only the thiophene unit, but also the substituent on the imidazole nitrogen. Noteworthily, replacing the thiophene with the benzothiophene, the fatigue resistance is significantly improved, the centre absorption bands of the closed forms shift from 572 nm (L3) to 550 nm (L2), and the colours of the solutions change from pale pink in L3 to red-purple in L2. Additionally, the Stokes shift (Δν) values of L3 in various solvents display good linear relationships with the donor number (DN) of the solvents, and the solvent polarity parameter Δf.
合成并表征了五种以2-(2-吡啶基)咪唑为乙烯桥的二芳乙烯衍生物(PI-BTEs)。PI-BTEs(L1–L5)的结构和性能不仅可以通过噻啉单元进行修改,还可以通过咪唑氮上的取代基进行调整。值得注意的是,用苯并噻吩替代噻啉后,耐疲劳性显著提高,闭合形式的中心吸收带从572 nm(L3)位移到550 nm(L2),溶液的颜色从L3中的浅粉色变为L2中的红紫色。此外,L3在各种溶剂中的斯托克斯位移(Δν)值与溶剂的供体数(DN)和溶剂极性参数Δf表现出良好的线性关系。