Facile Iodine Detection via Fluorescence Quenching of β‐Cyclodextrin:Bimane‐Ditriazole Inclusion Complexes

Ultrasensitive and versatile hydrogen peroxide sensing via fluorescence quenching

Reported herein is an ultra-sensitive turn-off fluorescence sensor for hydrogen peroxide based on its reaction with bimane 1. This reaction is highly efficient, resulting in a detection limit of 7.9 pM. It also maintains sensor efficacy when adsorbed on paper and enables both solution-state and vapor-phase detection.

Highly tunable bimane-based fluorescent probes: design, synthesis, and application as a selective amyloid binding dye

Small molecule fluorescent probes are indispensable tools for a broad range of biological applications. Despite many probes being available, there is still a need for probes where photophysical properties and biological selectivity can be tuned as desired. Here, we report the rational design and synthesis of a palette of fluorescent probes based on the underexplored bimane scaffold. The newly developed probes with varied electronic properties show tunable absorption and emission in the visible region with large Stokes shifts. Probes featuring electron-donating groups exhibit rotor effects that are sensitive to polarity and viscosity by "intramolecular charge transfer" (ICT) and twisted intramolecular charge transfer (TICT) mechanisms, respectively. These properties enable their application as "turn-on" fluorescent probes to detect fibrillar aggregates of the α-synuclein (αS) protein that are a hallmark of Parkinson's disease (PD). One probe shows selective binding to αS fibrils relative to soluble proteins in cell lysates and amyloid fibrils of tau and amyloid-β. Finally, we demonstrate the diagnostic potential of the probe in selectively detecting αS fibrils amplified from PD with dementia (PDD) patient samples.

Thioxobimanes

Dioxobimanes, colloquially known as bimanes, are a well-established family of N-heterobicyclic compounds that share a characteristic core structure, 1,5-diazabicyclo[3.3.0]octadienedione, bearing two endocyclic carbonyl groups. By sequentially thionating these carbonyls in the syn and anti isomers of the known (Me,Me)dioxobimane, we were able to synthesize a series of thioxobimanes, representing the first heavy-chalcogenide bimane variants. These new compounds were extensively characterized spectroscopically and crystallographically, and their aromaticity was probed computationally. Their potential role as ligands for transition metals was demonstrated by synthesizing a representative gold(I)-thioxobimane complex.

Optical Chemical Sensing of Iodide Ions: A Comprehensive Review for the Synthetic Strategies of Iodide Sensing Probes, Challenges, and Future Aspects

Among several anions, iodide (I^- ) ions play a crucial role in human biological activities. In it's molecular form (I₂ ), iodine is utilized for several industrial applications such as syntheses of medicines, fabric dyes, food additives, solar cell electrolytes, catalysts, and agrochemicals. The excess or deficiency of I^- ions in the human body and environmental samples have certain consequences. Therefore, the selective and sensitive detection of I^- ions in the human body and environment is vital for monitoring their overall profile. Amongst various analytical techniques for the estimation of I^- ions, optical-chemical sensing possesses the merits of high sensitivity, selectivity, and utilizing the least amount of sensing materials. The distinctive aims of this manuscript are (i) To comprehensively review the development of optical chemical sensors (fluorescent & colorimetric) reported between 2001-2021 using organic fluorescent molecules, supramolecular materials, conjugated polymers, and metal-organic frameworks (MOFs). (ii) To illustrate the design and synthetic strategies to create specific binding and high affinity of I^- ions which could help minimize negative consequences associated with its large size and high polarizability. (iii) The challenges associated with sensitivity and selectivity of I^- ions in aqueous and real samples. The probable future aspects concerning the optical chemical detection of I^- ions have also been discussed in detail.

A dipodal bimane-ditriazole-diCu(II) complex serves as an ultrasensitive water sensor

An ultrasensitive fluorescent water sensor based on a dipodal bimane-Cu(II) complex is reported here. This complex, which is non-fluorescent in the absence of water, demonstrates a remarkable turn-on fluorescence in the presence of extremely low (0.000786% v/v) concentrations of water, via highly selective water-induced displacement of copper and restoration of the innate bimane fluorescence.

Highly Sensitive Water Detection Through Reversible Fluorescence Changes in a syn-Bimane Based Boronic Acid Derivative

Reported herein is a fluorometric and colorimetric sensor for the presence of trace amounts of water in organic solvents, using syn-bimane based boronate ester 1. This sensor responds to the presence of water with a highly sensitive turn-off fluorescence response, with detection limits as low as 0.018% water (v/v). Moreover, analogously high performance was observed when compound 1 was adsorbed on filter paper, with the paper-based sensor responding both to the presence of liquid water and to humid atmospheres. Reusability of the paper-based sensor up to 11 cycles was demonstrated, albeit with progressive decreases in the performance, and 1H NMR and mass spectrometry analyses were used to explain the observed, hydrolysis-based sensor response.

Supramolecular Association between γ-Cyclodextrin and Preyssler-Type Polyoxotungstate

The development of hybrid materials based on polyoxometalates constitutes a strategy for the design of multifunctional materials. The slow evaporation of an aqueous solution of [NaP₅W₃₀O₁₁₀]¹⁴⁻ in the presence of γ-Cyclodextrin (γ-CD) led to the crystallization of a K₆Na₈{[NaP₅W₃₀O₁₁₀]•(C₄₈H₈₀O₄₀)}•23H₂O (NaP₅W₃₀•1CD) supramolecular compound, which was characterized by single-crystal X-ray diffraction, IR-spectroscopy, thermogravimetric and elemental analyses. Structural analysis revealed the formation of 1:1 {[NaP₅W₃₀O₁₁₀]•[γ-CD]}¹⁴⁻ adduct in the solid state. Studies in solution by cyclic voltammetry, electrochemical impedance spectroscopy, ¹H NMR spectroscopy, and ³¹P DOSY, have demonstrated weak interactions between the inorganic anion and the macrocyclic organic molecule.