Feeling blue: the luminescence of a triarylboron compound has a high quantum yield (at least 0.64) over a wide temperature range (-50 to +100 °C) and changes from green to blue as the temperature is increased. The luminescence color was determined by the population of the two distinct excited-state conformations-a local excited state (high temperature) and a twisted intramolecular charge-transfer state (low temperature).

We report a simple hard template strategy to prepare multi-shelled titania hollow spheres, which showed enhanced photocatalytic activities in comparison with sphere-in-sphere structures and nanoparticles.

Although highly useful in supramolecular chemistry, pillararenes lack a fluorophore in their skeleton. Here we present BowtieArene, a novel fluorescent dual macrocycle, featuring a central tetraphenylethylene‐derived fluorophore and two pillar‐like, pentagon‐shaped cavities which are comparable to pillar[5]arene. This concisely prepared, figure‐of‐eight molecule exhibits vapor absorption and host–guest capabilities, as well as intriguing switchable fluorescence. The fluorochromism of BowtieArene can be triggered by multiple external stimuli including solvent, vapor, and mechanical force, with excellent reversibility and stability. Experimental and theoretical evidence indicate that the fluorochromism should be closely related to molecular packing.

Polymeric micelles are being investigated as chemotherapy drug delivery carriers using ultrasound as a trigger mechanism. The aim of this paper is to measure the release of Doxorubicin (Dox) from the core of unstabilized Pluronic P105 micelles, Pluronic P105 micelles stabilized with an interpenetrating network of N,N-diethylacrylamide, and micelles of poly(ethylene oxide)-b-poly (N-isopropylacrylamide)-b-poly(oligolactylmethacrylate) with stabilized cores. An ultrasonic exposure chamber with fluorescence detection was used to measure the release of the antineoplastic agent from both stabilized and unstabilized micelles. The release of Dox at 37 degrees C from unstabilized Pluronic appears to be several times higher than release from the more stabilized and crosslinked copolymers at the same temperature. Although there is a difference in the amount of release between the different compounds, the onset of release occurs at about the same ultrasonic power density for all carriers investigated in this study. The threshold of drug release for all the compounds correlates to the emergence of subharmonic peaks detected in the acoustic spectra. We hypothesize that shearing events caused by cavitating bubbles play an important role in the acoustically activated release of chemotherapy agents delivered from various polymeric drug delivery vehicles.

A series of water-soluble naphthyl terminal-decorated dendrimers G0-3NapH were synthesized. Fluorescence studies reveal that strong interactions among peripheral chromophores occur in these dendrimers according to the intensive excimer emission and the low fluorescence quantum yields (Phi(f) = 0.12, 0.097, 0.065, and 0.062 for G0-3NapH). Through assembly of dendrimer with cucurbit[7]uril (CB[7]), the well-defined pseudorotaxane assemblies GnNapH x xCB[7] (x = 4, 8, 16, 32 for n = 0-3, respectively) form and the energy dissipation is entirely suppressed, resulting in a dramatic increase of the fluorescence quantum yields of dendrimers (Phi(f) = 0.18, 0.19, 0.19, and 0.20 for 0-3 generations, respectively). The noncovalent modification is a reversible process, and CB[7] can be unthreaded from the dendrimer periphery by adding 1-amimoadamantane, which can form a more stable complex with CB[7]. Furthermore, 9-anthracenecarboxylic acid (AN), an energy acceptor, was introduced into the dendritic system to investigate the harvested energy utilization. Steady-state fluorescence investigations demonstrate that the energy transfer efficiencies from naphthyl to AN in G3NapH x 32 CB[7]-AN and G2NapH x 16 CB[7]-AN are enhanced 100 and 70% compared with those without CB[7] complexation. This study provides a new strategy for developing controllable light-harvesting or -emitting dendritic systems.

Well‐dispersed silver nanoparticles were successfully fabricated within poly[(N‐isopropylacrylamide)‐co‐(acrylic acid)] [P(NIPAM‐co‐AA)] microgel particles which were synthesized with different cross‐linking densities. Their structures were studied by field‐emission scanning electron microscopy, transmission electron microscopy, UV‐vis spectroscopy, X‐ray diffraction and FT‐IR spectroscopy. The interactions between the microgel particles and the incorporated silver nanoparticles were investigated by X‐ray photoelectron spectroscopy. The results revealed that there was charge transfer from the carbonyl groups of the microgel particles to the silver nanoparticles. Moreover, as the diameter of the AgNPs decreases, the charge‐transfer efficiency increases accordingly. The P(NIPAM‐co‐AA)/AgNPs hybrid microgel particles were thermoresponsive and their behavior completely reversible with several heating/cooling cycles.magnified image

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A few of excited state intramolecular proton transfer (ESIPT) compounds have been discovered for their aggregation induced emission enhancement (AIEE). To understand the AIEE mechanism, an ESIPT compound BTHPB (N-(4-(benzo[d]thiazol-2-yl)-3-hydroxyphenyl)benzamide) with simple structure was designed and synthesized. BTHPB showed apparent AIEE property and the emission efficiency was observed as high as 0.27 in the aggregates. On the basis of viscochromism experiments and calculations employing the linear coupling model, the restriction of the rotation between the two subunits taken place in ESIPT was considered as the main factor for the AIEE. The micro- and femtosecond transient absorption experiments offered evidence for the considerations. Additionally, we also observed a negative effect of aggregation on the fluorescence emission in the system. So the AIEE of ESIPT compound BTHPB originated from the combination effects of positive and negative factors induced by the aggregation.