Optical Chemosensors for Cations Based on 1,8-Naphthalimide Derivatives

This review presents the examples of fluorescent sensors for metal cations based on a 1,8-naphthalimide optical platform and covers the main advances in this field for the last decade. The mechanisms of the generation of an optical signal are discussed in detail. Special attention is given to the authors' own works.

Squaraine-Based Optical Sensors: Designer Toolbox for Exploring Ionic and Molecular Recognitions

Small molecule-based chromogenic and fluorogenic probes play an indispensable role in many sensing applications. Ideal optical chemosensors should provide selectivity and sensitivity towards a variety of analytes. Synthetic accessibility and attractive photophysical properties have made squaraine dyes an enticing platform for the development of chemosensors. This review highlights the versatility of modular assemblies of squaraine-based chemosensors and chemodosimeters that take advantage of the availability of various structurally and functionally diverse recognition motifs, as well as utilizing additional recognition capabilities due to the unique structural features of the squaraine ring.

Supramolecular Interactions in Aromatic Structures for Non-Optical and Optical Chemosensors of Explosive Chemicals

The scientific investigation based on the molecular design of aromatic compounds for high-performance chemosensor is challenging. This is because their multiplex interactions at the molecular level should be precisely determined before the desired compounds can be successfully used as sensing materials. Herein, we report on the molecular design of chemosensors based on aromatic structures of benzene as the organic motif of benzene-1,3,5-tricarboxamides (BTA), as well as the benzene pyrazole complexes (BPz) side chain, respectively. In the case of BTA, the aromatic benzene acts as the centre to allow the formation of π–π stacking for one-dimensional materials having rod-like arrangements that are stabilized by threefold hydrogen bonding. We found that when nitrate was applied, the rod-like BTA spontaneously formed into a random aggregate due to the deformation of its hydrogen bonding to form inactive nitroso groups for non-optical sensing capability. For the optical chemosensor, the aromatic benzene is decorated as a side-chain of BPz to ensure that cage-shaped molecules make maximum use of their centre providing metal-metal interactions for fluorescence-based sensing materials. In particular, when exposed to benzene, Cu-BPz displayed a blue-shift of its original emission band from 616 to 572 nm (Δ = 44 nm) and emitted bright orange to green emission colours. We also observe a different mode of fluorescence-based sensing materials for Au-BPz, which shows a particular quenching mechanism resulting in 81% loss of its original intensity on benzene exposure to give less red-orange emission (λ = 612 nm). The BTA and BPz synthesized are promising high-performance supramolecular chemosensors based on the non-optical and optical sensing capability of a particular interest analyte.

Optical Chemosensors for Gas Phase Detection of Aldehydes: Mechanism, Material Design and Application

Because of their high hazard and presence in various common scenarios (e.g., workplace, residence or bio-conversion systems), aldehydes have attracted enormous attention in research and development of chemical sensors and...

Optical chemosensors for the detection of proximally phosphorylated peptides and proteins

This review details optical detection methods for proximal multi-site phosphorylation, a critical post-translational modification in protein biology.

Indium(III)-catalyzed solvent-free multicomponent [2+2+1+1]-annulation to polycyclic functionalized fused pyridines as potential optical chemosensors

An In(III)-catalyzed solvent-free one-pot [2+2+1+1]-annulation for the construction of highly fused polycyclic functionalized pyridines is described as a novel green approach . This unique reaction yields a wide range of...

Perylene Imide-Based Optical Chemosensors for Vapor Detection

Perylene imide (PI) molecules and materials have been extensively studied for optical chemical sensors, particularly those based on fluorescence and colorimetric mode, taking advantage of the unique features of PIs such as structure tunability, good thermal, optical and chemical stability, strong electron affinity, strong visible light absorption and high fluorescence quantum yield. PI-based optical chemosensors have now found broad applications in gas phase detection of chemicals, including explosives, biomarkers of some food and diseases (such as organic amines (alkylamines and aromatic amines)), benzene homologs, organic peroxides, phenols and nitroaromatics, etc. In this review, the recent research on PI-based fluorometric and colorimetric sensors, as well as array technology incorporating multiple sensors, is reviewed along with the discussion of potential applications in environment, health and public safety areas. Specifically, we discuss the molecular design and aggregate architecture of PIs in correlation with the corresponding sensor performances (including sensitivity, selectivity, response time, recovery time, reversibility, etc.). We also provide a perspective summary highlighting the great potential for future development of PIs optical chemosensors, especially in the sensor array format that will largely enhance the detection specificity in complexed environments.