Research On The Design、Synthesis And Application Of Ferrocene And Carbazole Multichannel Probes

New molecular probes containing ferrocene groups have a fast electron-transfer rate and exhibit excellent charge/discharged properties can be applied in molecular recognition and as electrochemical sensors.Meanwhile,carbazole and naphthalimide fluorescent dyes have good planar conjugation properties,intramolecular charge transfer and high fluorescence quantum yield.These two kinds of fluorescent dyes are also widely used.In this paper,four kinds of multichannel fluorescent probes were designed and synthesized by using ferrocene,carbazole and naphthalimide as models to detect Cu²⁺,Hg²⁺,pH and H₂S in water environment and living cells.At the same time,the synthesis and recognition mechanism of new ferrocene-based probes were studied.The main contents are as follows:In the first part,ferrocenyl dithiocarbamate derivatives were synthesized by one-pot method using ferrocenylhydrazone（1 equiv.）and ammonium dithiocarbamate（3 equiv.）and LiO^tBu（3 equiv.）,dioxane（3 mL）under 90 ^oC inert gas for 12 hours.The yield of products was 21-81%.The structures of products 3a and 3e were confirmed by single crystal X-ray diffraction.The method is simple,mild and has good universality of substrates.At the same time,this method also provides a new way to synthesize new ferrocene-based probes containing nitrogen and sulfur atoms.In the second part,a novel multichannel probe 3-1 ferrocenyl-naphthalimide was designed and synthesized by using an easy method.The color of the solution containing probe 3-1 changed from yellow to colorless upon the addition of Cu²⁺and Hg²⁺,respectively.Interestingly,probe3-1 exhibitedhighlyselective fluorescent turn-on for Cu²⁺and turn-off for Hg²⁺in aqueous solution.The probe 3-1was a electrochemical Cu²⁺and Hg²⁺ion sensor in which the Fc/Fc⁺redox couple was significantly shifted(ΔE_1/2=178 mV andΔE_1/2=53 mV)on complexation,respectively.Therefore,probe 3-1 can act as a naked-eye chemosensor,electrochemical and a fluorescent probe for Cu²⁺and Hg²⁺,respectively.Furthermore,this is the first reported that the probe can bifunctional fluorescent detect intracellular Cu²⁺and Hg²⁺by fluorescent imaging studies.（?）In the third part,we have designed and synthesized 1-substituted and1,1′-disubstituted ferrocene-based unsymmetrical azines under metal-free conditions.The crystal structure of 3k,5i and 5g revealed that conjugative interactions between the ferrocene,phenyl rings with the entire azine fragment exists.Furthermore,our electrochemical and optical analysis provided support for extended conjugation,which suggested larger substituent effect in this system.Density functional theory calculations also supported the results.Thus,these results reflected a stronger conjugative interaction between the ferrocene,phenyl rings with the entire azine fragment.At the same time,it provides a theoretical basis for the design and application of ferrocene-based azine probes.In the fourth part,we developed the 1–Hg²⁺complex can monitor a wide range of acidic pH（1.0-7.0）simply by observing the color change of aqueous solution with good fluorescent stability（>120 min）and reversibility.Meanwhile,at acidity（pH=4）,the probe can also be applied in living cell by imaging.Furthermore,chemosensor5-1 can be used as colorimetric and turn-on fluorescent probe for determination of Hg²⁺ions in practical systems and living cells with low detection limit（73 nM）.Considering these merits,chemosensor 5-1 provides a useful guidance for the design of new colorimetric and fluorescent Hg²⁺ions chemosensor and pH indicator.（?）In the fifth part,ferrocenyl-based carbazole derivative has been synthesized by a simple one-step reaction.Meanwhile,The newly synthesized receptor 6-1 displayed reversible fluorescent“turn on”response toward Hg²⁺with good quantum yield in aqueous environment.The color of the solution containing receptor 6-1 changed from colorless to yellow upon the addition of Cu²⁺ions.Therefore,receptor 6-1 can act as a fluorescent chemosensor for Hg²⁺and a naked-eye probe for Cu²⁺in aqueous environment.Quantification of absorption titration analysis shows that the detection limit was 6.15×10^-7 M for 1-Cu²⁺and 3.16×10^-7 M for 1-Hg²⁺,respectively.The experimental results show that the ferrocene group plays a crucial role in the ion recognition performance of the receptor.Finally,the receptor 6-1 has been used successfully for determination of Hg²⁺in living cells.（?）In the sixth part,the first fluorescent probe 7-1 was developed to detect H₂S and tBuO.redox cycle in living cells.Upon the addition of H₂S,the color of the probe 7-1solution changed from yellow to colorless.Meanwhile,the probe 7-1 displayed excellent properties such as good selectivity,qualitative detection（1-10μM）,low detection limit（21 nM）,and very fast response times（<50 s）for monitor of H₂S.The probe 7-1 is successfully used to real-time imaging the variation of H₂S and t BuO.in living cells.These merits play a crucial role in the H₂S detection in consideration of the fast metabolism in homeostasis regulation.（?）...