Department of Chemistry, Indian Institute of Technology Madras (IIT M), Chennai 600 036, India.
Department of Chemistry, Mrinalini Datta Mahavidyapith, Birati, Kolkata 700051, India.
Langmuir. 2023 Apr 4;39(13):4739-4755. doi: 10.1021/acs.langmuir.3c00144. Epub 2023 Mar 20.
A pyrene-based highly emissive low-molecular-weight organogelator, [2-(4-fluorophenyl)-3-(pyren-1-yl)acrylonitrile] (F1), is presented, which divulges thixotropic and thermochromic fluorescence switching via reversible gel-to-sol transition and tremendous superhydrophobicity (mean contact angles: 149-160°), devoid of any gelling and/or hydrophobic units. The rationale for the design strategy reveals that the restricted intramolecular rotation (RIR) in J-type self-assembly promotes F1 for the prolific effects of aggregation- and gelation-induced enhanced emission (AIEE and GIEE). Meanwhile, hindrance in charge transfer via the nucleophilic reaction of cyanide (CN) on the C═C unit in F1 facilitates the selective fluorescence "turn-on" response in both solution [9:1 (v/v) DMSO/water] and solid state [paper kits] with significantly lower detection limits (DLs) of 37.23 nM and 13.4 pg/cm, respectively. Subsequently, F1 discloses CN modulated colorimetric and fluorescence "turn-off" dual-channel response for aqueous 2,4,6-trinitrophenol (PA) and 2,4-dinitrophenol (DNP) in both solution (DL = 49.98 and 44.1 nM) and solid state (DL = 114.5 and 92.05 fg/cm). Furthermore, the fluorescent nanoaggregates of F1 in water and its xerogel films permit a rapid dual-channel "on-site" detection of PA and DNP, where the DLs ranged from nanomolar (nM) to sub-femtogram (fg) levels. Mechanistic insights reveal that the ground-state electron transfer from the fluorescent [F1-CN] ensemble to the analytes is responsible for anion driven sensory response, whereas the unusual inner filter effect (IFE) driven photoinduced electron transfer (PET) was responsible for self-assembled F1 response toward desired analytes. Additionally, the nanoaggregates and xerogel films also detect PA and DNP in their vapor phase with reasonable percentage of recovery from the soil and river water samples. Therefore, the elegant multifunctionality from a single luminogenic framework allows F1 to provide a smart pathway for achieving environmentally benign real-world applications on multiple platforms.
一种基于芘的高度发光的低分子量有机凝胶剂，[2-(4-氟苯基)-3-(芘-1-基)丙烯腈]（F1），被呈现出来，它通过可逆的凝胶到溶胶转变和巨大的超疏水性（平均接触角：149-160°）揭示出触变性和热致变色荧光开关，而无需任何凝胶和/或疏水性单元。设计策略的原理表明，J 型自组装中的受限分子内旋转（RIR）促进了 F1 的聚集和凝胶诱导增强发射（AIEE 和 GIEE）的丰富效果。同时，氰化物（CN）在 F1 的 C═C 单元上的亲核反应阻碍了电荷转移，这促进了在溶液[9:1（v/v）DMSO/水]和固态[纸试剂盒]中选择性荧光“开启”响应，分别具有显著更低的检测限（DL）为 37.23 nM 和 13.4 pg/cm。随后，F1 显示出 CN 调制的比色和荧光“关闭”双通道响应，用于水溶液中的 2,4,6-三硝基苯酚（PA）和 2,4-二硝基苯酚（DNP），分别在溶液（DL = 49.98 和 44.1 nM）和固态（DL = 114.5 和 92.05 fg/cm）中。此外，F1 在水中的荧光纳米聚集体及其干凝胶薄膜允许对 PA 和 DNP 进行快速双通道“现场”检测，其中 DL 范围从纳摩尔（nM）到亚飞克（fg）水平。机制研究表明，荧光[F1-CN]配合物到分析物的基态电子转移是阴离子驱动传感响应的原因，而异常的内滤效应（IFE）驱动的光致电子转移（PET）是自组装 F1 对所需分析物响应的原因。此外，纳米聚集体和干凝胶薄膜还可以在气相中检测 PA 和 DNP，并从土壤和河水样品中以合理的回收率进行检测。因此，来自单个发光骨架的优雅多功能性使 F1 能够为在多个平台上实现环境友好的实际应用提供一条智能途径。
