| Molecules and ions recognition is an important phenomenon in chemistry, biology and the materials science, and is the basical concept of supramolecular chemistry. The crucial recognition events occur in a much smaller world than that we are accustomed to. Therefore it needs to output the macroscopic signals with the special designed molecular detectors in order to understand and investigate the intermolecular act of recognition. In these signals, the most direct way is expressed by the light signal form, namely visualization. By introducing the special designed fluorescence probes into the target system, it will be able to transform the molecular recognition information into the fluorescence signals to transmit the outside world, thus will cause the communication between the human and the molecular possible and put up a bridge connecting the macrocosm and the microcosm, which is the key point and the hot spot in the current molecule-ion probe research field. The present paper contains following several aspects:1. Cu2+ PET fluorescence probes in living cells:owing to the quenching nature of paramagnetism Cu2+ to the fluorescence molecule excited state, it is a challenging work to design the high selective and sensitive fluorescence enhancement Cu2+ fluorescence probe. The present paper designed and synthesized three Cu2+ fluorescence probes. Probe L1 (bis(2-hydroxyl-naphthalene-carboxaldehyde) benzil dihydrazone) could selectively recognize Cu2+ by the fluorescence quenching way, but Hg2+ had disturbance. Probe L2 was synthesized from the reaction of 6-hydrazino-benzo [de] isoquinoline-1,3-diones with 4-tert-Butyl-2,6-diformyl-phenol. L2 could selectively distinguish Cu2+, and Hg2+ did not disturb it. L2 could be applied in the living cell fluorescence image. As a advancement of such research, by virtue of the electrochemistry survey and the quantum chemistry theoretical calculation, the electronic donor and the acceptor component which match with the Cu2+ redox potential was carefully chosen. The third probe L3, with appropriate front track energy level, was synthesized from the reaction of 7-diethylaminocoumarin-3-aldehyde with benzyl-dihydrazone. The fluorescence of L3 itself was extremely weak. After the Cu2+ coordinating, owing to the orbital energy level reasonable match, the photo induced electron transfer (PET) was blocked. As a result, the fluorescence of L3 obviously increased 75 times. L3 had many merits such as high selectivity, high sensitivity, good water-solubility, and so on. The focuse fluorescence image of living cell of L3 binding Cu2+ indicated L3 was an excellent Cu2+ fluorescence probe in the life system. 2. The design and synthesis of FRET ratio fluorescence probes and entire spectrum fluorescence molecules:It is currently a hot spot in fluorescence sensors research field to design and synthesis dual channel fluorescence probes based on fluorescence resonance energy (FRET) by virtue of fluorescence groups that energy match. In present paper, probes RC1 and RC2 were linked by rhodamine 6G (green fluorescence) or rhodamine B (red fluorescence) group as energy accepter with coumarin (blue fluorescence) group as energy donor through the ethylene diamine group. The selective and competitive experiments indicated the two probes could distinguish Cu2+ through FRET ratio fluorescence. CRB and CR6G were linked by rhodamine B or rhodamine 6G with coumarin through hydrazine group. Such two fluorescence probes could simultaneously distinguish Cu2+ and Hg2+ in aqueous solution by the UV-vis and fluorescence spectra double channels. Based on these probes linked by two fluorophores, the rare earth ion with sharp line emission spectrum was introduced to develop the three fluorescence channel. Single molecule compound RC1-Eu, containing RC1 (containing blue and green fluorophores) and Eu (launching red fluorescence), was synthesized through coordination reaction. By subtly regulating energy transfer process and the efficiency, RC1-Eu could separately launched blue, green and red three-primary colors, and could simultaneously emit blue, green, and red three-primary colors to produce white light when excitated at appropriate wavelength.3. The design and synthesis of fluorescence probes based on metal complexes target biological small molecules:Fluorescence probes target small biological molecules such as monosaccharides, amino acids, ribonucleic acids have important applications in life science and medicine. Based on the pure organic fluorescence probes research, the present paper designed and synthesized a series of fluorescence probes based on fluorescence active Ir, Eu and Ru complexes coordinated with phenanthroline derivatives. Probe Ir-OH (phenanthroline benzene boric acid Ir complex) could selectively recognize fructose in several mono-saccharides by fluorescence quenching approach. Ir-CHO (phenanthroline aldehyde Ir complex) and Eu-CHO (phenanthroline aldehyde Eu complex) could selectively recognize glutamic acid, glutathione and metallothionein by interacting with the particular fragments of them by the N-terminal acylation approach. Ru-N,N (N,N-dimethyl-phenanthroline Ru complex) could selectively distinguish ATP in twelve kinds of ribonucleic acid in CH3CN: H2O (9:1, v/v) solution by fluorescence enhancement response. |
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