Aryl-Phenanthro[9,10-d]imidazole: A Versatile Scaffold for the Design of Optical-Based Sensors

Abstract

Fluorescent and colorimetric sensors are important tools for investigating the chemical compositions of different matrices, including foods, environmental samples, and water. The high sensitivity, low interference, and low detection limits of these sensors have inspired scientists to investigate this class of sensing molecules for ion and molecule detection. Several examples of fluorescent and colorimetric sensors have been described in the literature; this Review focuses particularly on phenanthro [9,10d]imidazoles. Different strategies have been developed for obtaining phenanthro [9,10d]imidazoles, which enable modification of their optical properties upon interaction with specific analytes. These sensing responses usually involve changes in the fluorescence intensity and/or color arising from processes like photoinduced electron transfer, intramolecular charge transfer, intramolecular proton transfer in the excited state, and Forster resonance energy transfer. In this Review, we categorized these sensors into two different groups: those bearing formyl groups and their derivatives and those based on other molecular groups. The different optical responses of phenanthro [9,10-d]imidazole-based sensors upon interaction with specific analytes are discussed.

Selective pyrophosphate detection via metal complexes

“…Despite these challenges, significant progress has been made in inorganic PPi sensing [44][45][46][47][48]. Here, the focus will be on PPi sensors that utilize metal complexes and their structural design, sensing mechanism, selectivity, detection limit, and potential applications.…”

Self-assembled superstructures derived from suitably substituted phenanthro[9,10-d] imidazole-based Zn(ii)/Cd(ii) complexes for selective detection of acetone

“…16 Furthermore, metal complexes of phenanthro [9,10-d] imidazole showed promising photo or electroluminescence, nonlinear optical properties, tuneable self-assembly ability and were effectively involved in charge transfer process. [31][32][33][34][35][36][37] Along with their characteristic optical properties, these metal complexes also exhibit strong interactions with volatile organic compounds (VOCs), which can influence the electrical (surface voltage) properties of these metal complexes. VOCs are carbon-based and are usually generated from industrial production or indoor environments such as furnishing paints and building materials.…”

Polarity-Induced Morphological Transformation with Tunable Optical Output of Terpyridine–Phenanthro[9,10-d]imidazole-Based Ligand and Its Zn(II) Complexes with I–V Characteristics

“…It is well-known that different derivates of phenanthro­[9,10- d ]­imidazole, especially the 2-substituted ones, have been extensively used as luminescent sensors, photoactive materials, and OLED components for nonlinear optical applications. ,− On the other hand, terpyridine and its derivatives, especially the 4-substituted one, are well recognized in supramolecular chemistry due to their extended π-conjugation and their ability to coordinate with different transition metal ions. − The excellent photophysical, electrochemical, and catalytic properties − of these terpyridine derivatives and their corresponding metal complexes have led to finding their potential uses in numerous areas such as sensors, solar cells, energy storage, and molecular electronics . Therefore, the design of a small π-conjugated molecular system having both these phenanthro­[9,10- d ]­imidazole and 4-substituted terpyridine moieties is extremely desirable from a supramolecular point of view and expected to exhibit characteristic tunable self-assembly and optical and electronic properties, which can make this system a promising module for device applications.…”