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Aggregation‐induced emission (AIE) luminogens are attractive dyes to probe polymer properties that depend on changes in chain mobility and free volume. When embedded in polymers the restriction of intramolecular motion (RIM) can lead to their photoluminescence quantum yield (PLQY) strong enhancement if local microviscosity increases (lowering of chain mobility and free volume). Nonetheless, measuring PLQY during stimuli, i.e. heat or mechanical stress, is technically challenging; thus, emission intensity is commonly used instead, assuming its direct correlation with the PLQY. Here, by using fluorescence lifetime as an absolute fluorescence parameter, it is demonstrated that this assumption can be invalid in many commonly encountered conditions. To this aim, different polymers are loaded with tetraphenylenethylene (TPE) and characterized during the application of thermal and mechanical stress and physical aging. Under these conditions, polymer matrix transparency variation is observed, possibly due to local changes in refractive index and to the formation of microfractures. By combining different characterization techniques, it is proved that scattering can affect the apparent emission intensity, while lifetime measurements can be used to ascertain whether the observed phenomenon is due to modifications of the photophysical properties of AIE dyes (RIM effect) or to alterations in the matrix optical properties. [ABSTRACT FROM AUTHOR]

The interaction between two fluorophores dansyl moieties (Dns) and Dns.H(super +) is investigated in a reference compound obtained by derivatizing 1,6-hexanediamine with two densyl units. It is shown that the reference compound upon monoprotonation shows an almost complete quenching of the typical fluorescence of both the Dns and the Dns.H(super +) units.

Research has been conducted on the mono- and bis-phosphine diphenyl-substituted ruthenium porphyrin complexes. The photochemical and electrochemical properties of these complexes have been investigated and the role of different ligands in the physiochemical behavior of ruthenium(II) porphyrin complexes is discussed.

The bis-bipyridine-phosphine-oxide ligand forms complexes with Gd(sup)3+, Tb(sup)3+, and Eu(sup)3+ and the complexes exhibit anion dependent photophysical properties. Data indicate that a 7- and 11-fold increase, respectively, in the luminescence is seen when nitrate anions are added to an acetonitrile solution containing the ligand complexed with Eu and Tb ions.

Research is presented concerning the use of nuclear magnetic resonance and dynamic light scattering to study the aggregation of silver nanocrystals which have been stabilized by chemisorption.

A photoredox catalytic synthesis of functionalized 2‐aminofurans is proposed starting from α‐halo carbonyl substrates and N‐allenamides. The protocol proves to be efficient and sustainable thanks to: i) the use of visible light as green energy source, ii) the redox‐neutral nature of the transformation, allowing to avoid additives and strong oxidants, iii) the mild reaction conditions and the functional groups tolerance, iv) the low photocatalyst loading and the absence of excess reagents, v) the one‐pot formation of three new bonds in a domino sequence. According to our mechanistic hypothesis, the transformation is configured as a double radical‐polar crossover reaction, in which the photocatalyst is excited, oxidized and reduced twice for each molecule of 2‐aminofuran produced. The novelty of the designed synthetic approach also lies in the use of N‐allenamides as substrates, which, after the addition of the first electrophilic radical, preserve a further reactive π‐system, making possible the addition of a second α‐keto radical and enabling the installation of a keto functionality at a remote position. The good yields, the broad scope, and the possibility to further synthetically elaborate the obtained furans make this protocol particularly promising for the construction of useful products. [ABSTRACT FROM AUTHOR]

Four unsymmetrical covalently linked porphyrin dimers were synthesized and their electrochemical, spectroelectrochemical and/or photophysical characteristics were investigated. Computed energy transfer rate constants were observed to be consistent with the empirical data and indicated that the energy transfer mechanisms are best represented by a Foster process. Highly efficient and directional energy transfer processes were observed.