Solvent-sensitive charge-transfer absorption behaviours and dual-emissive fluorescent properties of a thiazole-conjugated pyridinium complex
作者:Zhan-Xian Li、Chun-Hu Xu、Wei Sun、Yan-Chun Bai、Chao Zhang、Chen-Jie Fang、Chun-Hua Yan
DOI:10.1039/b819016j
日期:——
neutral electron donor Et3N, only I− shows a similar influence on the absorption spectrum of 4-Me++ to that of bromide anion, confirming the bromide-dependent spectral properties of 4-MeB. With the help of theoretical calculations, the absorption in visible region is attributed to the charge-transfer from bromide anion to thiazolyl-pyridinium cation, which is tuned by the distance between the bromide
合成了一种新型的荧光团,即1-(乙氧基-羰基-甲基)-4- [2-(5-甲氧基)噻唑基]溴化吡啶鎓(4-MeB),并对其光物理性质进行了研究。在具有较大介电常数(ε)的溶剂中,4-MeB被离子化为自由离子,在UV区显示出以噻唑基-吡啶鎓阳离子为中心的π→π*电子跃迁吸收带。在具有较小ε值的溶剂中,例如四氢呋喃 (THF), 1,4-二恶烷 (二恶烷) 和 乙酸乙酯(EtOAc),4-MeB以紧密离子对的形式存在,并在可见光区和UV区同时显示特征性的溴离子依赖性吸收。在其他一些阴离子,如PF 6 - ,我-和Cl - ,和中性电子供体的Et 3 N,只有我-节目上的吸收光谱相似的影响4-ME + +至溴化物阴离子的,证实了4-MeB的溴化物依赖性光谱特性。借助理论计算,可见光区域的吸收归因于从溴化物阴离子到噻唑基-吡啶鎓阳离子的电荷转移,该电荷转移通过溴化物阴离子与噻唑基-吡啶基部分之间的距