Gandra Upendar Reddy, Lo Rabindranath, Managutti Praveen B, Butt Abdul Mannan, Reddy Pogula Sreekanth, Qurashi Ahasan Ul Haq, Mohamed Sharmarke, Mohideen M Infas H
Department of Chemistry, Khalifa University of Science and Technology, Abu Dhabi, P.O. Box 127788, United Arab Emirates.
Institute for Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstr. 8, D-07743 Jena, Germany.
Analyst. 2025 Jan 27;150(3):489-497. doi: 10.1039/d4an01265h.
In this report, we successfully engineered a novel probe based on an acceptor-donor-acceptor (A-D-A) architecture featuring dicyanovinyl-substituted thieno[3,2-]thiophene, termed DCVTT. The designed probe self-assembles into luminous nanoparticles (DCVTT NPs) upon introducing mixed aqueous solutions. These fluorescent nanostructures served as a ratiometric probe for detecting cyanide (CN) ions in aqueous-based environments, owing to the robust Intramolecular Charge Transfer (ICT) characteristics of DCVTT. The A-D-A substituents in DCVTT significantly enhanced ICT behavior by promoting more efficient electron transfer between the donor and acceptor groups. This improved electron transfer process leads to heightened sensitivity in detection applications. In the case of cyanide (CN) sensing, this enhanced ICT behavior manifests as a strong colorimetric response, allowing for a visible color change before and after interaction with cyanide. Speculation regarding the interaction mechanism between DCVTT and CN is proposed based on the findings of various experimental analyses. The detection limit (LOD) for DCVTT in identifying CN is 0.83 nM, significantly lower than the CN concentration thresholds deemed safe by the World Health Organization (WHO) and the United States Environmental Protection Agency (EPA). Time-Dependent Density Functional Theory (TD-DFT) has been utilized to theoretically analyze the optical properties of DCVTT both before and after the introduction of the CN ions. A paper-based test strip was developed to demonstrate its practical application to enable efficient qualitative CN detection by visual inspection. Furthermore, this sensing platform demonstrates highly accurate quantitative detection of CN in apple seeds. No prior reports have utilized fluorescence techniques to estimate apple seeds' CN levels.
在本报告中，我们成功设计了一种基于供体-受体-供体（A-D-A）结构的新型探针，其特征为二氰基乙烯基取代的噻吩并[3,2-b]噻吩，称为DCVTT。在引入混合水溶液后，所设计的探针自组装成发光纳米颗粒（DCVTT NPs）。由于DCVTT具有强大的分子内电荷转移（ICT）特性，这些荧光纳米结构可作为比率探针，用于检测水基环境中的氰化物（CN）离子。DCVTT中的A-D-A取代基通过促进供体和受体基团之间更有效的电子转移，显著增强了ICT行为。这种改进的电子转移过程提高了检测应用中的灵敏度。在氰化物（CN）传感方面，这种增强的ICT行为表现为强烈的比色响应，使得与氰化物相互作用前后会出现明显的颜色变化。基于各种实验分析的结果，提出了关于DCVTT与CN之间相互作用机制的推测。DCVTT识别CN的检测限（LOD）为0.83 nM，显著低于世界卫生组织（WHO）和美国环境保护局（EPA）认为安全的CN浓度阈值。利用含时密度泛函理论（TD-DFT）从理论上分析了引入CN离子前后DCVTT的光学性质。开发了一种纸质测试条以证明其实际应用，通过目视检查能够高效地进行定性CN检测。此外，该传感平台在苹果籽中对CN进行了高精度的定量检测。此前尚无利用荧光技术估算苹果籽中CN含量的报道。
