We report unusual photophysical properties observed on two newly designed 3-hydroxychromone derivatives exhibiting the excited-state intramolecular proton transfer (ESIPT) reaction. The efficiency of ESIPT reaction is greatly enhanced upon excitation with high energy quanta to S ( > 1) levels in low-polarity solvents. Based on detailed analyses of excitation and emission spectra as well as time-resolved emission kinetics we derive that conditions, in which this phenomenon contradicting Kasha's rule is observed, are quite different from that for observation of anti-Kasha emission.
View Article and Find Full Text PDFExploiting our recently developed bilayer interface methodology, together with a new wide energy-gap, low LUMO acceptor (A) and the designated donor (D) layers, we succeeded in fabricating an exciplex-based organic light-emitting diode (OLED) systematically tuned from blue to red. Further optimization rendered a record-high blue exciplex OLED with η(ext) of 8%. We then constructed a device structure configured by two parallel blend layers of mCP/PO-T2T and DTAF/PO-T2T, generating blue and yellow exciplex emission, respectively.
View Article and Find Full Text PDFNovel water-soluble noncovalent adducts of the heterometallic copper subgroup complexes and human serum albumin (HSA) display strong phosphorescence, internalize into HeLa cells and can be used in time-resolved fluorescent imaging.
View Article and Find Full Text PDFAmbipolar triplet hosts comprising 1,2,4-triazole and carbazole in ortho-positions have been developed. The blue PHOLED has a high current efficiency of 47.1 cd A(-1), power efficiency of 41.
View Article and Find Full Text PDFTwo pyrimidine chelates with the pyridin-2-yl group residing at either the 5- or 4-positions are synthesized. These chelates are then utilized in synthesizing of a new class of heteroleptic Ir(III) metal complexes, namely [Ir(b5ppm)2(fppz)] (1), [Ir(b5bpm)2(fppz)] (2), [Ir(b4bpm)2(fppz)] (3), and [Ir(b5bpm)(fppz)2] (4), for which the abbreviations b5ppm, b5bpm, b4bpm, and fppz represent chelates derived from 2-t-butyl-5-(pyridin-2-yl)pyrimidine, 2-t-butyl-5-(4-t-butylpyridin-2-yl)pyrimidine, 2-t-butyl-4-(4-t-butylpyridin-2-yl)pyrimidine, and 3-trifluoromethyl-5-(pyridin-2-yl) pyrazole, respectively. The single crystal X-ray structural analyses were executed on 1 to reveal their coordination arrangement around the Ir(III) metal element.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2013
A simple three-layer interfacial-type yellow emission exciplex device with an external quantum efficiency as high as 7.7% has been successfully achieved by combining conformation compatible C3-symmetric hole-transporting TCTA and electron-transporting 3P-T2T. The excellent and balanced charge-transporting properties of TCTA and 3P-T2T and the large energy-levels offset (0.
View Article and Find Full Text PDFA tetradentate bis(pyridylpyrazolate) chelate, L, is assembled by connecting two bidentate 3-(trifluoromethyl)-5-(2-pyridyl)pyrazole chelates at the 6 position of the pyridyl fragment with a phenylamido appendage. This chelate was then utilized in the synthesis of three osmium(II) complexes, namely, [Os(L)(CO)2] (4), [Os(L)(PPh2Me)2] (5), and [Os(L)(PPhMe2)2] (6). Single-crystal X-ray structural analyses were executed on 4 and 5 to reveal the bonding arrangement of the L chelate.
View Article and Find Full Text PDFThe mouse leucine-rich repeats and WD repeat domain containing 1 (lrwd1) gene is located on chromosome 5qG2 and spans over 13 kilobases. It encodes a novel protein of 648-amino acid protein that shares 78.3% amino acid sequence identity with the human LRWD1 protein.
View Article and Find Full Text PDFBackground: DAZ gene family is crucial for human spermatogenesis that requires the precise co-ordination of cell cycle events. CDC25A is recognized as the downstream substrate of DAZ gene family and is thought to function on the M-phase regulation of cell cycles. We investigated the expression profiles of CDC25A in the testes of infertile men and evaluated the relationship between CDC25A levels and testicular phenotype, clinical hormonal parameters and sperm retrieval results.
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