Novel PAMAM Dendron as a Bichromophoric Probe Based on Rhodamine 6G and 1,8-Naphthalimide

A Study of Small Molecule-Based Rhodamine-Derived Chemosensors and their Implications in Environmental and Biological Systems from 2012 to 2021: Latest Advancement and Future Prospects

Rhodamine-based chemosensors have sparked considerable interest in recent years due to their remarkable photophysical properties, which include high absorption coefficients, exceptional quantum yields, improved photostability, and significant red shifts. This article presents an overview of the diverse fluorometric, and colorimetric sensors produced from rhodamine, as well as their applications in a wide range of fields. The ability of rhodamine-based chemosensors to detect a wide range of metal ions, including Hg+2, Al3+, Cr3+, Cu2+, Fe3+, Fe2+, Cd2+, Sn4+, Zn2+, and Pb2+, is one of their major advantages. Other applications of these sensors include dual analytes, multianalytes, and relay recognition of dual analytes. Rhodamine-based probes can also detect noble metal ions such as Au3+, Ag+, and Pt2+. They have been used to detect pH, biological species, reactive oxygen and nitrogen species, anions, and nerve agents in addition to metal ions. The probes have been engineered to undergo colorimetric or fluorometric changes upon binding to specific analytes, rendering them highly selective and sensitive by ring-opening via different mechanisms such as Photoinduced Electron Transfer (PET), Chelation Enhanced Fluorescence (CHEF), Intramolecular Charge Transfer (ICT), and Fluorescence Resonance Energy Transfer (FRET). For improved sensing performance, light-harvesting dendritic systems based on rhodamine conjugates has also been explored for enhanced sensing performance. These dendritic arrangements permit the incorporation of numerous rhodamine units, resulting in an improvement in signal amplification and sensitivity. The probes have been utilised extensively for imaging biological samples, including imaging of living cells, and for environmental research. Moreover, they have been combined into logic gates for the construction of molecular computing systems. The usage of rhodamine-based chemosensors has created significant potential in a range of disciplines, including biological and environmental sensing as well as logic gate applications. This study focuses on the work published between 2012 and 2021 and emphasises the enormous research and development potential of these probes.

Ratiometric fluorescence sensing with logical operation: Theory, design and applications

The construction of ratiometric fluorescence sensing logic systems has gradually become a hot topic in fluorescence analysis, due to the multi-target analysis potential of logic operations and the high specificity and selectivity of ratiometric fluorescence sensing. In this paper, the basic principles of various logic functions implemented in ratiometric fluorescence detection are discussed in the context of sensing mechanisms, and the strategies for constructing logic systems in different ratiometric fluorescence sensing application areas are summarized. Although there are limitations such as cumbersome operations and complicated experiments, ratiometric fluorescence sensing logic circuits that combine the visualization of logic operations and the accuracy of ratiometric fluorescence are still worthy of in-depth study. This review may be useful for researchers interested in the construction of logic operations based on ratiometric fluorescence sensing applications.

Exploring the Aggregation and Light-Harvesting Aptitude of Naphthalimide-Based Amphiphile and Non-amphiphile AIEgen

Herein, we report a comparative study of two naphthalimide-tethered amphiphile and non-amphiphile with their aggregation-induced emission properties. A synthetic modulation of a hydrophobic tail on the framework repressed the ACQ-phoric fluorophore to an AIEgen. L₁ and L₂ remain in the dispersed form in DMF and exhibits aggregation and intense emission signal in aqueous media. Microscopy detailing of the aggregating process has been analyzed. Not only the AIEgens are emissive in water but also they are emissive in the solid state. The natural light-harvesting process is mimicked by the aggregated state, establishing an energy transfer process between L₁ and commercial dye. Disaggregation of the AIEgen has also been utilized in the detection of nitroaromatics. Analytical utility of the AIE-gen is being demonstrated concerning the detection of explosives in aqueous media.

A smart chemosensor: Discriminative multidetection and various logic operations in aqueous solution at biological pH

A novel rhodamine-pyrazole based molecular probe was designed and easily synthesized. The probe could to detect several analytes in aqueous solution at biological pH (HEPES, pH = 7.2). Several heavy metal cations, including Cu²⁺, Fe³⁺, Al³⁺, Hg²⁺ and Ni²⁺ were detected discriminately by the probe. Also, the novel compound exhibited a good sensory selectivity towards S₂O₅^2- by both absorption and emission spectra. Moreover, probe/Cu²⁺ complex could to detect several anions, including F^-, CN^-, S^2-, CH₃COO^-, CO₃^2- and NO₂^-. Furthermore, the probe exhibited a high potential to work as a molecular system able to perform a number of logical operations such as AND, NAND, NOR and INHIBIT logic gates.

Synthesis of a single 1,8-naphthalimide fluorophore as a molecular logic lab for simultaneously detecting of Fe3+, Hg2+ and Cu2

A novel fluorescence sensing 1,8-naphthalimide fluorophore is synthesized and investigated. The novel probe comprising two different binding moieties is capable to detect selectively Fe³⁺ over the other representative metal ions as well as a combination of biologically important cations such as Fe³⁺, Cu²⁺ and Hg²⁺ in the physiological range without an interfering effect of the pHs. Due to the remarkable fluorescence changes in the presence of Fe³⁺, Hg²⁺ and Cu²⁺ ions, INH and AND logic gates are executed and the system is able to act as a single output combinatorial logic circuit with three chemical inputs.

Synthesis, fluorescence-sensing and molecular logic of two water-soluble 1,8-naphthalimides

Two novel highly water-soluble fluorescence sensing 1,8-naphthalimides are synthesized and investigated. The novel compounds are designed on the "fluorophore-receptor₁-spacer-receptor₂" model as a molecular fluorescence probe for determination of cations and anions in 100% aqueous media. The novel probes comprising N-imide and N-phenylpiperazine or morpholine substituents are capable to operate simultaneously via ICT and PET signaling mechanism as a function of pH and to recognize selectively Cu²⁺ and Hg²⁺ over the other representative metal ions. Due to the remarkable fluorescence changes in the presence of protons, hydroxyl anions, Hg²⁺ and Cu²⁺, INH and doubly disabled INH logic gates are executed and the systems are able to act as a single output combinatorial logic circuit with four chemical inputs.