Accessing the long-lived triplet excited states in bodipy-conjugated 2-(2-hydroxyphenyl) benzothiazole/benzoxazoles and applications as organic triplet photosensitizers for photooxidations

A novel benzothiazole-based enaminone as a fluorescent probe for highly selective and sensitive detection of CN−

A novel benzothiazole derived enaminone BTP as fluorescent probe for CN⁻ recognition has been developed.

A new type of triphenylamine based coumarin–rhodamine hybrid compound: synthesis, photophysical properties, viscosity sensitivity and energy transfer

A series of novel core modified triphenylamine coumarin–rhodamine systems (compounds MCMR, MCDR and DCMR) was designed and synthesized by incorporating a coumarin moiety on one and a rhodamine moiety on the other phenyl ring of the triphenylamine molecular skeleton.

Highly fluorescent extended 2-(2′-hydroxyphenyl)benzazole dyes: synthesis, optical properties and first-principle calculations

Restoration of ESIPT upon protonation was demonstrated in an extended-hydroxybenzothiazole derivative in which it was fully inhibited in the neutral state.

An efficient and green synthesis of novel benzoxazole under ultrasound irradiation

Ultrasound as green process and an alternative energy source was investigated for the environmentally benign synthesis of novel benzoxazoles from different azo-linked salicylic acid derivatives and 2-amino-4-chlorophenol in short reaction time and high yield. These benzoxazole compounds have been characterized by elemental analysis, FT-IR, (1)H NMR and (13)C NMR spectroscopy.

White light emissive molecular siblings

White-light emission from boron based molecular siblings.

Tumor-targeting, enzyme-activated nanoparticles for simultaneous cancer diagnosis and photodynamic therapy

Specific targeting towards tumors and the on-site activation of photosensitizers to diagnose tumors and reduce side effects for patients are currently the main challenges for photodynamic therapy (PDT) in the clinic. Herein, uniform diiodostyryl bodipy conjugated hyaluronic acid nanoparticles (DBHA-NPs) were successfully synthesized. The evaluation of their PDT effect at both a cellular level and in animal models of tumor-bearing mice shows that the DBHA-NPs present a remarkable suppression of tumorous growth due to their specific targeting and enhanced permeability and retention (EPR) effect. More importantly, the enzyme-activated "self-assembly and disaggregation" behavior in tumors can lead to the on-site activation of DBHA-NPs, which can diagnose the tumor exactly and reduce the side effects for patients significantly. These findings confirm that DBHA-NPs have significant potential for photodynamically activated cancer theranostics in a clinical setting.

A novel excited-state intramolecular proton transfer (ESIPT) dye with unique near-IR keto emission and its application in detection of hydrogen sulfide

A new ESIPT dye of benzothiazole with a conjugative electron acceptor was discovered and synthesized. Due to its unique NIR keto emission and a large Stokes shift, it was used to develop a fluorescent probe for sensitive and selective detection of hydrogen sulfide.

A multifunctional probe with aggregation-induced emission characteristics for selective fluorescence imaging and photodynamic killing of bacteria over mammalian cells

A multifunctional probe aggregation-induced emission-Zinc(II)-dipicolylamine (AIE-ZnDPA) is developed for selective targeting, fluorescence imaging, and photodynamic killing of both Gram-positive and Gram-negative bacteria over mammalian cells. The probe has significant advantages in simple probe design, enhanced fluorescence upon bacteria binding, excellent photostability, and broad-spectrum antibacterial activity with almost no harm to mammalian cells.

Halogenated boron-dipyrromethenes: synthesis, properties and applications

Synthesis and properties of halogenated boron-dipyrromethenes and their applications in developing various BODIPY systems are described in this review.

Solvatochromism of BODIPY-Schiff dye

A boron-dipyrrin chromophore connected with an o-hydroxyaryl aldimine by a diazo bridge (BODIPY-Schiff dye) has been developed. The photophysical properties of the BODIPY-Schiff dye have been investigated with UV, steady-state, and time-resolved fluorimetry. The spectral features have been characterized with respect to density functional theory and time-dependent density functional theory. The conformational analysis of the studied compound has been accomplished both in the ground and excited states. A scheme of the processes occurring in the BODIPY-Schiff dye has been proposed.

Describing excited state intramolecular proton transfer in dual emissive systems: a density functional theory based analysis

The excited state intramolecular proton transfer (ESIPT) reaction taking place within 2-(2-hydroxyphenyl)benzoxazole (HBT) and two recently experimentally characterized napthalimide derivatives-known as N-1 and N-4-has been investigated in order to identify and test a possible protocol for the description and complete mechanistic and electronic characterization of the reaction at the excited state. This protocol is based on density functional theory, time-dependent density functional theory, and a recently proposed electron density based index (DCT). This method is able to identify all stable species involved in the reaction, discriminate between possible reaction pathways over potential energy surfaces (PES), which are intrinsically very flat and difficult to characterize, and quantitatively measure the excited state charge transfer character throughout the reaction. The photophysical properties of the molecules (i.e., absorption and emission wavelength) are also quantitatively determined via the implicit inclusion of solvent effects in the case of toluene and, the more polar, tetrahydrofuran. The accuracy obtained with this protocol then opens up the possibility of the ab initio design of molecules exhibiting ESIPT for tailored applications such as highly selective molecular sensors.

Design, synthesis and photophysical studies of dipyrromethene-based materials: insights into their applications in organic photovoltaic devices

This review article presents the most recent developments in the use of materials based on dipyrromethene (DPM) and azadipyrromethenes (ADPM) for organic photovoltaic (OPV) applications. These chromophores and their corresponding BF2-chelated derivatives BODIPY and aza-BODIPY, respectively, are well known for fluorescence-based applications but are relatively new in the field of photovoltaic research. This review examines the variety of relevant designs, synthetic methodologies and photophysical studies related to materials that incorporate these porphyrinoid-related dyes in their architecture. The main idea is to inspire readers to explore new avenues in the design of next generation small-molecule and bulk-heterojunction solar cell (BHJSC) OPV materials based on DPM chromophores. The main concepts are briefly explained, along with the main challenges that are to be resolved in order to take full advantage of solar energy.

Excited state intramolecular proton transfer in π-expanded phenazine-derived phenols

Two previously inaccessible analogs of 10-hydroxybenzo[h]quinoline were prepared via a straightforward strategy comprising the formation of π-expanded phenazines skeleton followed by C-H acetoxylation at position 10. Two bis-phenols possessing C2 and D2 symmetry were obtained in yields of 52% and 15%, respectively. The occurrence of excited state intramolecular proton transfer (ESIPT) was detected in all cases because steady state emission was observed only from the excited keto-tautomer. Additionally, a short-lived, ∼0.1 ps, emission decay was resolved by the femtosecond up-conversion technique at the blue side of the keto-tautomer emission band, 610 nm, and was attributed to the ESIPT, i.e., conversion from enol to keto tautomer. In comparison with the corresponding 10-hydroxybenzo[h]quinoline emissions, the emission spectrum of the π-expanded phenazine analogues were weaker but displayed a characteristic bathochromically shift into NIR region. These phenazine analogues constitute one of largest heterocycles for which ESIPT was unambiguously detected.