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基于汞离子促进硫羰基脱硫的不可逆反应,合成了两种分别含有丙烯酰基酰肼基硫脲基团和丙烯基酰肼基硫脲基团的罗丹明B荧光探针(RhBHA和RhBCH),用以高选择性、高灵敏度检测水溶液中的Hg2+离子.通过荧光发射光谱和可见光下颜色变化研究了硫羰基所处的化学环境对汞离子促进的脱硫反应的影响.研究结果表明,引入罗丹明B荧光生色团后,分子的“开环-闭环”转换过程与分子内氢键作用没有相互影响,分子内氢键加速了汞离子的脱硫反应,伴随“开环-闭环”转换过程的颜色变化通过肉眼即可观察到.此外,还研究了分子间氢键作用对脱硫反应速率的影响.通过加入汞离子后荧光强度随时间变化的跟踪发现,若溶剂与RhBHA形成分子间氢键作用,会使汞离子诱导的脱硫反应有所迟缓.这种分子间的氢键作用,对能促进快速脱硫反应的分子内氢键作用产生影响.
Two Rhodamine B fluorescent probes (RhBHA and RhBCH) containing acryloyl hydrazide thiourea groups and acrylyl hydrazinothiourea groups, respectively, were synthesized based on the irreversible reaction of mercury ions to promote thiourea desulfurization. Hg2 + ions in aqueous solution were detected with high selectivity and high sensitivity.The influence of the chemical environment of thiocarbonyl on the desulfurization reaction promoted by mercury ion was studied by fluorescence emission spectroscopy and color change under visible light.The results showed that the introduction of rhodamine B Fluorescent chromophores, the molecular “open-closed-loop ” conversion process and intramolecular hydrogen bonding interaction has no effect, intramolecular hydrogen bonding accelerated mercury ion desulfurization reaction, with “open-loop - closed loop ” conversion The color change of the process can be observed with the naked eye.In addition, the effect of intermolecular hydrogen bonding on the desulfurization reaction rate has also been studied.Tracking of the fluorescence intensity with time after addition of mercury ion shows that if the solvent and RhBHA form intermolecular hydrogen Key role, will make the mercury ion-induced desulfurization reaction slowed down.Such hydrogen bonds between molecules, can promote rapid desulfurization reaction of intramolecular hydrogen bonding effect.