A Series of Polyamide Receptor Based PET Fluorescent Sensor Molecules: Positively Cooperative Hg²⁺ Ion Binding with High Sensitivity

A series of PET fluorescent sensor molecules were designed and synthesized based on BODIPY fluorophore and polyamide receptors. Comparison of the photophysical properties of these sensor molecules, equipped with di-, tri-, and tetraamide receptor, provided a deep insight into the polyamide−Hg2+ interactions, and an unusual positively cooperative tetraamide−Hg2+ complexation was disclosed. In addition, sensor S3 displayed several favorable sensing properties

A Highly Selective and Sensitive Fluorescent Chemosensor for Hg²⁺ in Neutral Buffer Aqueous Solution

A selective and sensitive fluorescent chemosensor for Hg2+, which was composed of two aminonaphthalimide fluorophores and a receptor of 2,6-bis(aminomethyl)pyridine, was synthesized through the reaction of 2,6-bis(chloromethyl)pyridine and N-[2-(2-hydroxyethoxy)ethyl]-4-piperazino-1,8-naphthalimide. The chemosensor showed an about 17-fold increase in fluorescence quantum yield upon addition of 1 equiv of Hg2+ in neutral buffer aqueous solution, and the other common metal ions did not notably disturb the detection of Hg2+

A Rhodamine-Based Hg²⁺ Sensor with High Selectivity and Sensitivity in Aqueous Solution: A NS₂-Containing Receptor

A rhodamine-based sensor 1 was designed and synthesized by incorporation the rhodamine fluorophore and ionophore NS2 with high affinity to Hg2+. Sensor 1 exhibits a high selectivity and an excellent sensitivity and is a dual-responsive colorimetric and fluorescent Hg2+-specific sensor in aqueous buffer solution. In addition, the 1:1 binding mode was proposed based on the 1H NMR and ES(+)MS studies

Highly Efficient Energy Transfer in the Light Harvesting System Composed of Three Kinds of Boron−Dipyrromethene Derivatives

A light-harvesting system containing three kinds of BODIPY fluorophores was synthesized. It exhibited very strong absorption in the region from 300 to 700 nm, and the energy transfer within it was highly efficient

Detecting Hg²⁺ Ions with an ICT Fluorescent Sensor Molecule: Remarkable Emission Spectra Shift and Unique Selectivity

A fluorescent ratiometric Hg2+ ion sensor RMS, based on a coumarin platform coupled with a tetraamide receptor, is presented. This sensor, employing the ICT mechanism, could be used to specifically detect Hg2+ ions in a neutral buffered water solution with an ∼100-nm blue shift in emission spectra

Colorimetric and Ratiometric Fluorescent Chemosensor with a Large Red-Shift in Emission: Cu(II)-Only Sensing by Deprotonation of Secondary Amines as Receptor Conjugated to Naphthalimide Fluorophore

A new fluorescent probe N-butyl-4,5-di[2-(phenylamino)ethylamino]-1,8-naphthalimide 1 senses only Cu(II) among heavy and transition metal (HTM) ions by means of a colorimetric (primrose yellow to pink) method with a large red-shift in emission (green to red) attributed to the deprotonation of the secondary amines as a receptor conjugated to the naphthalimide fluorophore

2,3,6,7-Tetraamino-9,9-bis(2-ethylhexyl)fluorene: New Multifunctional Monomer for Soluble Ladder-Conjugated Molecules and Polymers

2,3,6,7-Tetraamino-9,9-bis(2-ethylhexyl)fluorene (TABEF), as a new multifunctional monomer for ladder-type conjugated molecules and polymers, was efficiently synthesized via a six-step procedure with an overall yield of 30%. Two isomeric ladder compounds based on TABEF building blocks were also synthesized and preliminarily studied

Efficient Synthesis of Regioisomerically Pure Bis(trifluoromethyl)-Substituted 3,4,9,10-Perylene Tetracarboxylic Bis(benzimidazole)

By a new strategy, two trifluoromethyl groups were efficiently introduced to highly insoluble n-type semiconductor 3,4,9,10-perylene tetracarboxylic bis(benzimidazole) (PTCBI), and for the first time we obtained three pure regioisomers of bis(trifluoromethyl)-substituted PTCBI, whose optical properties are different from one another

“Indanonalkene” Photoluminescence Platform: Application in Real-Time Tracking the Synthesis, Remodeling, and Degradation of Soft Materials

In this Article, we present a strategy to visually track chemically triggered covalent bonding processes in gelation, remodeling, and degradation of soft materials, i.e., hydrogels, based on a new photoluminescence platform. Initially in the development of photoluminophors named “indanonalkenes”, turn-on emission can be tracked and quantified in the optical reaction between a conjugate acceptor and amine derivatives. On this basis, fluorescence enhancement and mechanical changes were recorded during the gelation process through amine–thiol exchanges under organic and aqueous conditions. Next in macromolecular remodeling, we realized a stimulus-induced transformation of one architecture into another one, exploiting the orthogonality of chemical covalent bonding that could be visualized using luminescence. Furthermore, the hydrogel network can be degraded to release the coupling partner induced by ethylene diamine, and the process can be monitored using fluorescence changes and quantified through gel permeation chromatography, while the released components can be utilized again to regenerate a new hydrogel. In addition, the photographic images provide alternatives to fluorescence spectra and can be digitally processed to quantify the macroscopic changes, resulting in a photographic imaging approach. The real-time observation and quantification of chemically triggered polymeric formation, morphology, and degradation through luminescence in spatial and time scales herald a new generation of “smart” materials

Isomeric Boron−Fluorine Complexes with Donor−Acceptor Architecture: Strong Solid/Liquid Fluorescence and Large Stokes Shift

Novel isomeric fluorine−boron complexes with donor−acceptor architecture have been efficiently synthesized and well characterized. Significant features, such as strong solid and liquid fluorescence, unusual large Stokes shifts, and lower LUMO levels and higher HOMO levels, are observed in these potential multifunctional molecules