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Transition metal ions play an important role in the field of chemistry, life sciences, environmental science, and medicine, which has become one of the important tasks of analytical chemistry detection of transition metal ions in solution. Fluorescent molecular probes to molecular recognition into fluorescence signal can be felt with high sensitivity, good selectivity switch operation can achieve submicron subnanometer spatial resolution of visual ability and sub-millisecond time-resolved capacity, in situ detection (fluorescence imaging) and the use of optical fiber for long-range detection and many other advantages, fluorescence sensing Cation Recognition rapid development. Is well known, the transition metal and heavy metal ions, since they are mostly empty track exists, can occur in the transition metal ions from the fluorophore to the electron transfer or energy transfer, while the heavy metal ions can be induced to spin-orbit coupling thereby quenching fluorescence, so early detection the the class metal ions more based on fluorescence quenching. For the detection sensitivity, the fluorescence enhancement method is more superior than the fluorescence quenching method. Therefore, the use of fluorescence enhancement method to identify the transition metal or heavy metal ions has become a research hotspot in recent years. Rhodamine B has a high extinction coefficient, preferably the fluorescence quantum yield, good water-soluble, non-toxic, and low cost, is a commonly used fluorescent carrier. Chapter II, we have synthesized a new fluorescent probe molecules (Rhodamine B lactam derivatives), this compound compounds reported in the literature only a key change, turned on by the recognition of mercury ion selective the effective recognition of the copper ions, and no response, the linear range of 2.5 × 10-6-5.0 × 10-5 M, the detection limit: 6.1 x 10-7 M mercury ions. Mercury ion has a strong thiophilic, we designed and synthesized another probe (Rhodamine B sulfur-substituted products). Compared with rhodamine B, the compound occurs only an atom changes, i.e. O is replaced by S, the introduction of a mercury atom, can be efficiently with mercury ion complexation, rhodamine annular structure is destroyed, and to generate a ring-opening compounds. Mercury ion probe molecules combined solution from colorless, non-fluorescent, to the solution turns purple, produced a strong fluorescence. Of the compound in the concentration of Hg2 5 × 10-6-1.4 × 10-5 M range, there is a good linearity. The lowest detection limit: 4.3 × 10-7 M. Naphthalimide-based compound because of its having a good optical properties: good light stability, and quantum yield, the fluorescence emission wavelength of a moderate and large displacement Stocks, is an ideal phosphor carrier. This article, we have designed and synthesized based molecular resonance energy transfer (FRET) and light-induced electron transfer (PET) new ratio-type fluorescent probe 2 - (N-butyl-1, 8 - naphthalimide -4 - piperazine piperazinyl - methyl) -6 - (anthracene-9 - methyl - piperazin-yl - methyl) pyridine, to achieve a single excitation, dual emission detection mercury ions. Mercury ion the linear response range of 2.4 × 10-7-8.6 × 10-5 M, the detection limit: 4.6 x 10-8 M.
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