Optical Sensing (Nano)Materials Based on Benzimidazole Derivatives

Abstract

Benzimidazole derivatives are well-known biologically active substances, and therefore, they are mostly synthesised for therapeutic purposes. However, such heteroaromatic molecular systems own structure-related properties that enable a variety of applications, especially in optical science. Multifunctionality of the benzimidazole unit, such as electron accepting ability, π-bridging, chromogenic pH sensitivity/switching and metal-ion chelating properties, makes it an exceptional structural candidate for the design of optical chemical sensors and functional materials. Development of smart molecular sensors and novel (nano)materials is the emerging trend observed in materials and optical sensing science in general, in which the benzimidazole molecular systems strongly contribute and participate. In this chapter, we summarised recent advances in optical sensing (nano)materials that incorporate the benzimidazole structural moiety. Solid-state optical sensing systems, including self-assembled molecular materials based on benzimidazoles, are reviewed and discussed. In addition, immobilisation of benzimidazole derivatives onto or into various substrates and matrices, such as organic and inorganic polymers, bulk membranes and nanoparticles, utilising different chemical and physical methods, is presented and analysed.

Sulfide-Induced Concentration-Dependent Distinct Optical Response: Unique Chromogenic Probe Developed for Analyzing Fecal Contamination in Water and Intracellular Imaging Applications

“…2,24,25 Moreover, the planar benzimidazole moiety is known for self-agglomeration in the aqueous medium. 26 As expected, we observed a broadening of the emission band of probe 2, attributable to the aggregation of probe 2 molecules, as evident by the excitation spectra. 27 Interaction with Sulfide Ions in the Aqueous Medium.…”

“…We observed a bathochromic shift of the emission maximum with increasing solvent polarity, which indicates that the dipole–dipole interactions with solvent molecules probably stabilized the excited state of 2 more effectively than that of the ground state (Figure S2). ,, Moreover, the planar benzimidazole moiety is known for self-agglomeration in the aqueous medium . As expected, we observed a broadening of the emission band of probe 2, attributable to the aggregation of probe 2 molecules, as evident by the excitation spectra …”

Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications

“…Other reviews cover optical pH sensors based on swellable polymers on thin film composite optical waveguides for sensor applications (pH sensing included), 7 and the book series edited by Dakin and Culshaw (mainly on sensors for physical parameters) also contains a section on chemical sensors, pH included. 8 A rather specific review was presented 9 on the use of benzimidazole derivatives in various kind of optical detection schemes for various analytes and parameters, such as pH values. Both molecular benzimidazole probes and respective nanomaterial-based detection schemes are covered.…”

Spectroscopic and Computational Study of the Protonation Equilibria of Amino-Substituted benzo[b]thieno[2,3-b]pyrido[1,2-a]benzimidazoles as Novel pH-Sensing Materials

“…For ground-state calculations, all molecular geometries were optimized using a very efficient B3LYP/6-31+G(d) model, which was designed to provide highly accurate thermodynamic and kinetic parameters for various organic systems, in line with our earlier work [9,21]. To account for the solvent effects, during geometry optimization, we included the implicit SMD solvation model corresponding to pure solvents [25].…”

“…Owing to their excellent spectroscopic properties, as well as pronounced and diverse spectral responses, such derivatives offer promising applications in optoelectronics as optical lasers, fluorescence probes, organic luminophores or fluorescent dyes [5][6][7][8]. Among many heterocyclic derivatives developed as fluorescent organic sensors, benzimidazole derivatives play an important role and represent a special interest for organic chemists because of their eminent physico-chemical and spectroscopic characteristics [9,10]. Additionally, the benzimidazole framework, due to its structural similarity to naturally occurring purines, is widely incorporated in the structure of numerous biologically important natural and synthetic molecules and could interact with important biomacromolecules within living organisms [11][12][13].…”