Synthesis And Properties Of Molecular Logical Gate Based On BODIPY

The development of highly selective and sensitive chemosensors has become one of the most active areas in chemistry, especially in the biology and microenvironment areas. The remarkable progress in the development of molecular logic gates has brought chemists closer to the realization of molecular-scale calculator since the first report of molecular AND logic gate based on chemosensors by de Silva et al. Compared with the modem semiconductor IT industry, molecular logic gates can be viewed as computational devices that process physical or chemical "inputs" to generate "outputs" based on a set of logical operators. The molecular logic systems can also make themselves to convenient reconfiguring, especially for application in the life sciences. The "bottom-up" method exhibits a significant advantage over conventional semiconductor counterparts. As a consequence, molecular logic gates can be designed in chemical and intracellular sensing, small object recognition and intelligent diagnostics and so on.4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (hereafter abbreviated to BODIPY) dyes as rigid and cross-conjugated molecules have attracted increasing attention over the last decade compared with polycyclic aromatic hydrocarbons and other fluorescent dyes. BODIPY compound have outstanding photo-physical properties, for example, visible excitation wavelength, narrow and intense absorption and emission band, high molar extinction coefficients, high fluorescence quantum yields, relative insensitivity to changes in polarity and pH value, moderate redox potential, easy modified structure, nanosecond excited-state lifetimes, high photo-stability.Based on the above strategies and further introducing functional substituents at meso-position, we designed and synthesized two types of novel fluorescent probes based on BODIPY dyes, the results are summarized as follows:1. Introducing bipyridine substitunent at meso-position, we synthesized a new BODIPY derivative, which act as a fluorescent logic gate for Cu2+and HPO42-. Bright green fluorescence in C2H5OH is quenched upon the addition of Cu2+ion due to the oxidative PET process. Moreover, the fluorescence intensity is restored when the HPO42-is added to the complex. And the fluorescence "turn-off and "turn-on" mechanism is consistent with DFT calculation.2. We designed and synthesized a novel thiophene fused BODIPY derivatives through thiophene fused pyrrole. Since sulphur atom has a vacant3d orbital which can coordinate with heavy metal ions such as Hg2+ad Cu2+. Nitrophenyl and amino phenyl group have been introduced into meso-position, which act as a pH probe in the NIR region. These new BODIPYs may be applicable as molecular logical gates.