Chandrasekaran Yogesh, Venkatramaiah Nutalapati, Patil Satish
Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India), Fax.
Chemistry. 2016 Apr 4;22(15):5288-94. doi: 10.1002/chem.201504485. Epub 2016 Mar 1.
This study reports the synthesis and photophysical properties of a star-shaped, novel, fluoranthene-tetraphenylethene (TFPE) conjugated luminogen, which exhibits aggregation-induced blue-shifted emission (AIBSE). The bulky fluoranthene units at the periphery prevent intramolecular rotation (IMR) of phenyl rings and induces a blueshift with enhanced emission. The AIBSE phenomenon was investigated by solvatochromic and temperature-dependent emission studies. Nanoaggregates of TFPE, formed by varying the water/THF ratio, were investigated by SEM and TEM and correlated with optical properties. The TFPE conjugate was found to be a promising fluorescent probe towards the detection of nitroaromatic compounds (NACs), especially for 2,4,6-trinitrophenol (PA) with high sensitivity and a high Stern-Volmer quenching constant. The study reveals that nanoaggregates of TFPE formed at 30 and 70% water in THF showed unprecedented sensitivity with detection limits of 0.8 and 0.5 ppb, respectively. The nanoaggregates formed at water fractions of 30 and 70% exhibit high Stern-Volmer constants (Ksv=79,998 and 51,120 M(-1), respectively) towards PA. Fluorescence quenching is ascribed to photoinduced electron transfer between TFPE and NACs with a static quenching mechanism. Test strips coated with TFPE luminogen demonstrate fast and ultra-low-level detection of PA for real-time field analysis.
本研究报道了一种星形新型芴-四苯乙烯（TFPE）共轭发光体的合成及其光物理性质，该发光体表现出聚集诱导蓝移发射（AIBSE）。外围庞大的芴单元可防止苯环的分子内旋转（IMR），并诱导蓝移且增强发射。通过溶剂化显色和温度相关发射研究对AIBSE现象进行了研究。通过扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究了通过改变水/四氢呋喃（THF）比例形成的TFPE纳米聚集体，并将其与光学性质相关联。发现TFPE共轭物是一种有前景的用于检测硝基芳香化合物（NACs）的荧光探针，特别是对2,4,6-三硝基苯酚（PA）具有高灵敏度和高斯特恩-沃尔默猝灭常数。研究表明，在THF中30%和70%水含量下形成的TFPE纳米聚集体表现出前所未有的灵敏度，检测限分别为0.8和0.5 ppb。在水含量为30%和70%时形成的纳米聚集体对PA表现出高斯特恩-沃尔默常数（分别为Ksv = 79,998和51,120 M⁻¹）。荧光猝灭归因于TFPE和NACs之间具有静态猝灭机制的光致电子转移。涂有TFPE发光体的测试条展示了对PA的快速和超低水平检测，用于实时现场分析。
