Single molecule fluorescence microscopy has shown that samarium oxide nanoparticles efficiently catalyze the formation of coumarin 153 via a semi-heterogeneous catalytic process.

Samarium oxide nanoparticles (Sm 2 O 3 NP) were prepared photochemically for the first time. Characterization shows spherical, polydisperse Sm 2 O 3 NP stabilized by 4-HEBA, a substituted benzoic acid.The Sm 2 O 3 NP also possess Brønsted acidity. This new material may prove to be a potent heterogeneous acid catalyst.Scheme 1 Photochemical preparation of Sm 2 O 3 NP in CH 3 CN. The small arrow in eqn (2) denotes the eventual reduction of the intermediate to 4-HEBA. In eqn (3), n equals 1 or 2 but not 3, as metallic samarium has not been observed. Fig. 4 SEM image of Sm 2 O 3 NP after repeated exposure to 2 mM NaOH and subsequent washing with CH 3 CN.This journal is

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AILEEN FLVNN is a social worker in a general medical hospital. KATHRYN CAVE, GREGORY HODGSON, MARK PROUATT, AND WILLIAM SULTMANN are undergraduate psychology students. JAMES M. GARDNER if a Fellow of the American Association on Mental Deficiency and of the Australian Psychological Society. He is a former editorial board member of Professional Psychology and has been a consulting editor of several other journals. He is currently a professor in and Head of the Division of Applied Psychology, University of the Witwatersrand, Johannesburg, South Africa.

We present a hybrid nano-molecular system for optically activated, silver nanoparticle enhanced fluorescence in solution and in thin-polymer films, alongside single molecule level insights into the metal-enhanced fluorescence mechanism.

We report on heterogeneous dual photoredox-Lewis acid catalysis using a versatile and efficient nanocomposite: samarium oxide nanoparticle-decorated titanium dioxide. This emerging class of nanomaterials harnesses the Lewis acidity of the lanthanide, eliminates product contamination by the catalyst, and can be excited with visible light. Useful intermolecular and intramolecular net reductive and net neutral photoredox cyclization reactions are presented as examples of the general efficacy of this reusable heterogeneous nanocatalyst in synthetically relevant organic transformations.

Plasmonic metal nanoparticles can impact the behavior of organic molecules in a number of ways, including enhancing or quenching fluorescence. Only through a comprehensive understanding of the fundamental photophysical processes regulating nanomolecular interactions can these effects be controlled and exploited to the fullest extent possible. Metal-enhanced fluorescence (MEF) is governed by two underlying processes, increased rate of fluorophore excitation, and increased fluorophore emission, the balance between which has implications for optimizing hybrid nanoparticle–molecular systems for various applications. We report groundbreaking work on the use of single molecule fluorescence microscopy to distinguish between the two mechanistic components of MEF, in a model system consisting of two analogous boron dipyrromethene (BODIPY) fluorophores and triangular silver nanoparticles (AgNP). We demonstrate that the increased excitation MEF mechanism occurs to approximately the same extent for both dyes, but that the BODIPY with the higher quantum yield of fluorescence experiences a greater degree of MEF via the increased fluorophore emission mechanism and higher overall enhancement, as a result of its superior ability to undergo near-field interactions with AgNP. We foresee that this knowledge and methodology will be used to tailor MEF to meet the needs of different applications, such as those requiring maximum enhancement of fluorescence intensity or instead prioritizing excited-state photochemistry.

Solid niobium oxides (Nb 2 O 5 ·nH 2 O) and niobium phosphate were used as heterogeneous acid catalysts to promote the condensation between a switchable oxazine and a fluorescent coumarin in an aprotic solvent.The catalysts were found to promote the generation of an active methylene from the enamine-based portion of the oxazine, which was followed by a nucleophilic attack on the aldehyde functionality of the coumarin reagent. In the resulting system, the emission of the conjugated fluorophore can be observed at 670 nm and, thus, the processes occurring at the catalyst surface can be monitored in real time by total internal reflection fluorescence microscopy (TIRFM).