Photophysical Characterization (photophysical + characterization)

Distribution by Scientific Domains

Selected Abstracts

The Synthesis, Photophysical Characterization, and X-Ray Structure Analysis of Two Polymorphs of 4,4,-Diacetylstilbene

Cameron Pye
Abstract A palladium(II) acetate-catalyzed synthesis of 1 that utilizes the novel triazene 1-{4-[(E)-morpholin-4-yldiazenyl]phenyl}ethanone as a synthon is described. The room temperature absorption spectra of 1 in various solvents exhibited a ,,,* transition in the range of 330,350,nm. Compound 1 was observed to be luminescent, with room-temperature solution and solid-state emission spectra that exhibited maxima in the range 400,500,nm. All room-temperature absorption and emission spectra exhibited some degree of vibrational structure. The emission spectrum of 1 at 77,K in propanenitrile glass was broad and featureless with a maximum at 447,nm. Compound 1 crystallized as a yellow and colorless polymorph. X-Ray structure analyses of both of these polymorphs and 1-{4-[(E)-morpholin-4-yldiazenyl]phenyl}ethanone are presented. [source]

ChemInform Abstract: Crystal Growth, Structural Properties, and Photophysical Characterization of Ln4Na2K2M2O13 (M; Nb, Ta; Ln: Nd, Sm, Eu, Gd).

CHEMINFORM, Issue 46 2009
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Synthesis and Functionalization of Germanium Triphenylcorrolate: The First Example of a Partially Brominated Corrole

Sara Nardis
Abstract Ge complexes of 5,10,15-triphenylcorrole were prepared in refluxing dry DMF using GeCl4 as the source of Ge. Chromatographic separation of the crude reaction mixture afforded the ,-oxo dimer 1 and the methoxy derivative 2a. The corresponding chloride 2b can be obtained by treatment of 1 or 2a with HCl. The reaction of 2a with Br2 in CHCl3/py afforded the hexabromo derivative 3 as the main product, giving the first indication of the regioselective substitution of pyrroles B and C on the corrole ring. The fully brominated open-chain tetrapyrrole 4 was also characterized as a reaction by-product. Different partially brominated Ge complexes 5 and 6 have been obtained by variation of reaction conditions, while the heptabromo derivative was obtained in a mixture with the corresponding fully brominated Gecorrole. Photophysical characterization of Ge corrolates confirmed the high fluorescence quantum yield of such complexes, and also led to the first observation of phosphorescence emissions from corrole complexes. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Labeling of proteins with fluorescent probes: Photophysical characterization of dansylated bovine serum albumin,

Valeria Levi
Abstract Fluorescence spectroscopy is a widely used technique in biophysical studies. One of the strategies frequently used consists of labeling biomolecules with fluorescent probes, which have distinctive photophysical properties. This methodology allows the study of a wide variety of structural features of the biomolecule. We describe a simple laboratory activity for undergraduate Biophysical Chemistry courses. The experimental work includes two activities: labeling BSA with dansyl chloride and analyzing the resulting absorption and fluorescence spectra. The discussion of these activities helps students to understand the basis of fluorescence spectroscopy with emphasis in the application to biological systems. [source]

Preparation, characterization, and electrical properties of dual-emissive Langmuir-Blodgett films of some europium-substituted polyoxometalates and a platinum polyyne polymer

Li Liu
Abstract A new series of organometallic/inorganic composite Langmuir-Blodgett (LB) films consisting of a rigid-rod polyplatinyne polymer coordinated with 2,7-bis(buta-1,3-diynyl)-9,9-dihexylfluorene (denoted as PtP) as the ,-conjugated organometallic molecule, an europium-substituted polyoxometalate (POM; POM = Na9EuW10O36, K13[Eu(SiW11O39)2] and K5[Eu(SiW11O39)(H2O)2]) as the inorganic component, and an amphiphilic behenic acid (BA) as the auxiliary film-forming agent were prepared. Structural and photophysical characterization of these LB films were achieved by ,,A isotherms, absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunneling microscopy, and low-angle X-ray diffraction. Our experimental results indicate that stable, well-defined, and well-organized Langmuir and LB films are formed in pure water and POM subphases, and the presence of Eu-based POM in the subphase causes an area expansion. It is proposed that a lamellar layered structure exists for the PtP/BA/POM LB film in which the POM and PtP molecules can lay down with the interfacial planes. Luminescence spectra of the prepared hybrid LB films show that near-white emission spectra can be obtained due to the dual-emissive nature of the mixed PtP/POM blends. These Pt-polyyne-based LB films displayed interesting electric conductivity behavior. Among them, PtP/BA/POM 13-layer films showed a good electrical response, with the tunneling current up to 100 nA when the voltage was monitored between ,1 and 7 V. 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 879,888, 2010 [source]

Quantum Dot-based Energy Transfer: Perspectives and Potential for Applications in Photodynamic Therapy

Anna C. S. Samia
ABSTRACT Quantum dots have emerged as an important class of material that offers great promise to a diverse range of applications ranging from energy conversion to biomedicine. Here, we review the potential of using quantum dots and quantum dot conjugates as sensitizers for photodynamic therapy (PDT). The photophysics of singlet oxygen generation in relation to quantum dot-based energy transfer is discussed and the possibility of using quantum dots as photosensitizer in PDT is assessed, including their current limitations to applications in biological systems. The biggest advantage of quantum dots over molecular photosensitizers that comes into perspective is their tunable optical properties and surface chemistries. Recent developments in the preparation and photophysical characterization of quantum dot energy transfer processes are also presented in this review, to provide insights on the future direction of quantum dot-based photosensitization studies from the viewpoint of our ongoing research. [source]