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In efficient thermally activated delayed fluorescence (TADF) the excited chromophore alternates randomly between the singlet and triplet manifolds a large number of times before emission occurs. In this work, the average number of cycles [formula] is obtained and is shown to have a simple experimental meaning: [formula] is the intensification factor of the prompt fluorescence intensity, owing to the occurrence of TADF. A new method of data analysis for the determination of the quantum yield of triplet formation, combining steady-state and time-resolved data in a single plot, is also presented. Application of the theoretical results to the TADF of [70]fullerenes shows a general good agreement between different methods of fluorescence analysis and allows the determination of several photophysical parameters. [ABSTRACT FROM AUTHOR]

We prepared hybrid nanoparticles with a brightly fluorescent silica core and a biocompatible thermoresponsive polymer shell containing tumor-targeting folic acid (FA) groups. The silica core has a perylenediimide fluorescent dye anchored covalently to the structure for traceability and bioimaging applications. The polymeric shell was synthesized by reversible addition-fragmentation chain-transfer (RAFT) polymerization to guarantee the homogeneous size of the particle shell. The shell is composed of copolymer chains with one block of oligo(ethylene glycol)methacrylate and 2-(2′-methoxyethoxy)ethylmethacrylate with another block of the reactive monomer N-acryloxysuccinimide (NAS). The NAS groups were used to covalently attach a large amount of amino-functionalized FA to the particle shells to provide active targeting properties towards cancer cells and tissues. The targeting capability of the folate-containing nanoparticles was evaluated against NCI-H460 tumor cells, which overexpress folate receptors. The nanoparticles with FA show a higher uptake efficiency compared to that of the equivalent nanoparticles without FA. This result validates the imaging capabilities and active targeting efficiency of our nanoparticles, an important step towards the goal of developing vehicles for precision drug delivery systems that combine therapeutic and diagnostic (theranostic) functionalities with large drug payloads, active targeting, and stimuli-activated drug release. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nanoparticles with a PBMA coated perylenediimide-labeled silica core form flexible and transparent films. [•] Fluorescent silica nanoparticles are homogeneously distributed in the films. [•] The silica particles embedded in the films do not significantly hinder the diffusion process. [ABSTRACT FROM AUTHOR]

Abstract: A three-component condensation reaction between aminopyrazolo[3,4-d]pyrimidine, an aldehyde, and an isocyanide catalyzed by scandium triflate yields a series of heterocyclic derivatives of imidazo[1,2-c]pyrazolo[3,4-d]pyrimidine in good yields, exhibiting interesting fluorescent properties. [Copyright &y& Elsevier]

We prepared a series of substituted aminocyanopyrroles and another of aminocynaothiophenes. We describe an efficient new one-step synthetic strategy via the condensation of an alkyl sarcosinate and ethoxymethylenemalononitrile, through a Gewald-like reaction. The UV–visible absorption and steady-state and time resolved fluorescence properties of some representative compounds, as well as their acid-base behavior, is also presented. The compounds might be useful for medicinal applications and as bioimaging probes. Image 1 • A series of substituted aminocyanopyrrole esthers has been synthesized; • A series of substituted aminocyanotiophene esthers has also been synthesized; • Efficient one-pot synthetic strategies are described; • The fluorescence, UV–vis absorbance and acid-base behavior of the compounds is presented; • These compounds might be useful for medicinal applications and as bioimaging probes. [ABSTRACT FROM AUTHOR]