Preferences of rhodamine coupled (aminoalkyl)-piperazine probes towards Hg(II) ion and their FRET mediated signaling
Preferences of rhodamine coupled (aminoalkyl)-piperazine probes towards Hg(II) ion and their FRET mediated signaling
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DOI：
10.1039/c3ob40648b
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发表时间：
2013-08-14
影响因子：
3.2
通讯作者：
Bag, Bamaprasad
中科院分区：
文献类型：
--
作者：
Biswal, Biswonath;Bag, Bamaprasad
金属离子诱导的罗丹明偶联双-（氨基丙基）-哌嗪（1-3）和（氨基乙基）-哌嗪(4)探针在MeCN和MeCN- h2o二元混合介质中的吸收和发射信号模式表明，这些探针在MeCN中表现出不同程度的光信号扰动。它们的络合诱导信号可以在溶剂介质中存在水组分的情况下选择性地调谐到Hg(II)，其中金属-探针相互作用和金属离子的水化等竞争性相互作用是诱导水促进Hg（II）选择性的决定因素。在罗丹明偶联的双（氨基丙基）哌嗪受体的另一端附着另一个荧光团（分别为2和3中的蒽和硝基苯并呋喃唑基团），使这些探针能够促进络合诱导的荧光共振能量转移（FRET），从激发的荧光团到开环的罗丹明，同时通过操作PET抑制和罗丹明脱乙酰化过程做出贡献。在选择性Hg（II）络合作用下，这些探针在557 nm附近的吸收跃迁增强，从而导致溶液中无色到粉红色的变化，这意味着一种显色信号模式，而同时荧光扩增和/或FRET启动导致荧光信号传导，以促进低浓度下的检测。在其他竞争金属离子存在下的汞（II）选择性光物理光谱调制，以及它们在反阴离子或螯合剂（如EDTA或乙二胺）作用下的可逆双通道信号模式，确立了这些探针对汞（II）的高选择性、敏感和可逆的“OFF-ON-OFF”检测的潜力。与含有乙基间隔物的探针相比，在受体中含有丙基连接物的探针的络合诱导光信号模式（1-3）表明，具有取代的“氨基烷基-内酯化罗丹明”亚基的信号探针设计在有机-水混合介质中优先表现出Hg（II）选择性和敏感的双模式信号，而与柔性烷基间隔物的碳长度无关。
The metal ion induced absorption and emission signaling pattern of rhodamine coupled bis-(aminopropyl)-piperazine (1-3) and (aminoethyl)-piperazine (4) based probes evaluated in MeCN as well as in an MeCN-H2O binary mixture medium revealed that these probes exhibit optical signaling perturbations to a varying extent in MeCN, however, their complexation induced signaling could be tuned selectively towards Hg(II) in the presence of an aqueous component in the solvent medium where competitive interactions such as metal-probe interactions and hydration of metal ions play the determining factor to induce aqueous promoted Hg(II) selectivity. Attachment of another fluorophore (anthracene and nitrobenzofurazan moieties in 2 and 3 respectively) at the other end of the rhodamine coupled bis-(aminopropyl)-piperazine receptor enabled these probes to facilitate a complexation induced fluorescence resonance energy transfer (FRET) from the excited fluorophore to the ring-opened rhodamine along with contributions through operative PET inhibition and rhodamine delactonization processes. The enhancement in absorption transition of these probes at similar to 557 nm upon selective Hg(II)-complexation and consequent colourless to pink colour change in the solution imply a chromogenic signaling pattern whereas simultaneous fluorescence amplification and/or FRET initiation lead to fluorogenic signaling to facilitate detection at lower concentration. The Hg(II)-selective photo-physical spectral modulation in the presence of other competitive metal ions, and their reversible dual channel signaling pattern under the action of counter anions or chelating agents such as EDTA or ethylenediamine establish the potential of these probes for highly selective, sensitive and reversible 'OFF-ON-OFF' detection of Hg(II). The complexation induced optical signaling pattern of probes with a propyl-linker in their receptor (1-3) in comparison with that of 4 consisting of an ethyl-spacer indicate that signaling probe design with a substituted 'aminoalkyl-lactonized-rhodamine' subunit preferentially exhibit Hg(II) selective and sensitive dual mode signaling in an organic-aqueous mixture medium irrespective of carbon-length of the flexible alkyl spacer.