Wang Zhong-Xia, Yu Xian-He, Li Feng, Kong Fen-Ying, Lv Wei-Xin, Wang Wei
School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng 224051, China.
J Mater Chem B. 2018 Mar 28;6(12):1771-1781. doi: 10.1039/c7tb02708g. Epub 2018 Mar 7.
The shape of nanoparticles is decisive for their intrinsic physicochemical properties, as well as for the anisotropic behavior of individual particles in many instances. Herein, boron-doped nitrogen-rich carbon rugby ball-like nanodots (BNCRDs) have been synthesized by a heterophase polymerization route at a vital mass ratio of phenylboronic acid and uric acid in the precursor solution. Unexpectedly, the as-prepared BNCRDs showed stable dispersions of ellipsoidal carbonaceous polymer nanodots (rugby ball-like structures that are approximately 150 nm in length) as novel carbon dot derivatives. The anisotropic BNCRDs are water-soluble compounds that have highly enhanced photoluminescence (PL), which is accompanied by a large red shift of the emission peak upon the addition of Hg and is nearly quenched upon the addition of Cu. This is due to the chelation-enhanced fluorescence property of the BNCRDs following Hg complexation with sterically efficient heteroaromatics in the BNCRDs and the chelation enhancement quenching effect of the BNCRDs following Cu complexation with the N/O donor atoms of the surface of the BNCRDs, respectively. Importantly, the BNCRD PL, which is changed by Hg and Cu, exhibits high selectivity and sensitivity for the pyrophosphate ion (PPi) in the ranges 50 nM-280 μM and 10 nM-100 μM through a photoluminescent reset process, respectively, and could be attributed to the effective coordination/chelation interactions between Hg/Cu and the plentiful oxygen groups of PPi. These results indicate that anisotropic BNCRDs can act not only as a ratiometric sensor for Hg but also as a dual-mode PPi-selective sensor via ratiometric displacement and a competitive mechanism. With the broad diversity in the molecular backbone of the carbon dots via rich chemical routes, anisotropic BNCRDs have been developed with unique structural, electrical, and attractive functions, which greatly expands the research horizon of carbon-based composites.
纳米颗粒的形状对于其固有物理化学性质起着决定性作用，在许多情况下，对于单个颗粒的各向异性行为也是如此。在此，通过前驱体溶液中苯硼酸和尿酸的关键质量比，采用异相聚合路线合成了硼掺杂富氮碳橄榄球状纳米点（BNCRDs）。出乎意料的是，所制备的BNCRDs呈现出稳定分散的椭圆形碳质聚合物纳米点（长度约为150 nm的橄榄球状结构），作为新型碳点衍生物。各向异性的BNCRDs是水溶性化合物，具有高度增强的光致发光（PL），在加入Hg时发射峰有很大的红移，而在加入Cu时几乎猝灭。这分别归因于Hg与BNCRDs中空间高效杂芳烃络合后BNCRDs的螯合增强荧光特性，以及Cu与BNCRDs表面的N/O供体原子络合后BNCRDs的螯合增强猝灭效应。重要的是，受Hg和Cu影响而变化的BNCRD PL，通过光致发光重置过程，分别在50 nM - 280 μM和10 nM - 100 μM范围内对焦磷酸根离子（PPi）表现出高选择性和灵敏度，这可归因于Hg/Cu与PPi丰富的氧基团之间有效的配位/螯合相互作用。这些结果表明，各向异性的BNCRDs不仅可以作为Hg的比率传感器，还可以通过比率位移和竞争机制作为双模式PPi选择性传感器。通过丰富的化学路线，碳点分子骨架具有广泛的多样性，已开发出具有独特结构、电学和吸引人功能的各向异性BNCRDs，这极大地扩展了碳基复合材料的研究视野。
