A new class of rhodamine luminophores: design, syntheses and aggregation-induced emission enhancement

A new class of rhodamine luminophores, 3',3'-bis(oxospiroisobenzofuran)-3,7-bis(dialkylamino)benzopyrano-xanthene derivatives (ABPX), have been successfully developed. The emission behavior of ABPX series is directly opposite to the concentration quenching of conventional rhodamine dyes. ABPX series exhibit aggregation-induced emission enhancement (AIEE).     

Photoinduced methanol formation from methane and no at 275 k on highly dispersed vanadium oxide supported on vycor glass and its reaction intermediate species

UV irradiation at 275 K of the highly dispersed V/Vycor oxide catalyst in the presence of NO leads to the formation of N₂ and O₂. The decomposition reaction of NO proceeds photocatafytically. In the presence of CH₄, UV-irradiation of the catalyst at 275 K leads to the formation of C₂H₆ and C₂H₄, but this reaction is found to accompany the reduction of the catalyst as well as the formation of CH₃ radicals. A dynamic photoluminescence study of the catalyst in the absence and presence of the reactants indicates that the charge transfer excited triplet state of the surface vanadyl-species (V=O) plays a significant role in these photoinduced reactions of NO and CH₄. On the other hand, UV-irradiation of the catalyst at 275 K in the presence of a mixture of NO and CH₄ leads to the formation of CH₃OH in addition to the above products. The higher the ratio of NO/CH₄ in the mixture is, the larger the yield of CH₃OH becomes and the smaller the yields of C₂H₆ and C₂H₄ become, the reaction proceeding catalytically. Thus, the present results not only imply that the highly dispersed supported vanadium oxide catalysts can be utilized as a potential photocatalyst for de-NOx-ing and/or methane activation at normal temperature but also suggest that the photo-formed oxygen species from NO molecules plays a significant role in the photoinduced CH₃OH formation from CH₄ and NO on V/Vycor oxide catalysts at 275 K.     

Synthesis and properties of highly fluorescent indolizino[3,4,5-ab]isoindoles

We report here the synthesis, X-ray structures, optical and electrochemical properties, fabrication of light-emitting devices, and density functional calculations for indolizino[3,4,5-ab]isoindole (INI) derivatives. Strongly luminescent heterocycles based on the INI unit were synthesized by 1,3-dipolar cycloaddition reactions between pyrido[2,1-a]isoindole (PIS) and acetylene or ethylene derivatives. They are indolizino[3,4,5-ab]isoindoles 2-9 and 14-15, benzo[1',2'-1,2]indolizino[3,4,5-ab]isoindoles 10, pyridazino[4',5':1,2]indolizino[3,4,5-ab]isoindoles 12-13, and 2,3-hydropyridazino[4',5':1,2]indolizino[3,4,5-ab]isoindole-1,4-dione 11. The relative luminescence quantum yield can be as high as 90%. Their reduction and oxidation potentials and high luminescence can make these heterocycles possible alternatives to tris(8-hydroxyquinolinato)aluminum (Alq(3)). The brightness of the light-emitting device reached as high as 10(4) cd/m(2) and indolizino[3,4,5-ab]isoindole 3 emits beautifully blue light. The X-ray crystal structures of INI derivatives were obtained for the first time. The geometries obtained from X-ray data and density functional theory calculations shed more light on an interesting formally antiaromatic 16pi system, which is divided into 10pi and 6pi aromatic systems. We also report a relatively easy protonation of INI, which occurs at a carbon, rather than nitrogen atom.     

A local second-order Møller-Plesset method with localized orbitals: a parallelized efficient electron correlation method

Using orthogonal localized occupied orbitals we have developed and implemented a parallelized local second-order M?ller-Plesset (MP2) method based on the idea developed by Head-Gordon and co-workers. A subset of nonorthogonal correlation functions (the orbital domain) was assigned to each of the localized occupied orbitals using a distance criterion and excitations from localized occupied orbitals that were arranged into subsets. The correlation energy was estimated using a partial diagonalization and an iterative efficient method for solving large-scale linear equations. Some illustrative calculations are provided for molecules with up to 1484 Cartesian basis sets. The orbital domain sizes were found to be independent of the molecular size, and the present local MP2 method covered about 98%-99% of the correlation energy of the conventional canonical MP2 method.     

Method Development of Enantiomer Separations by Affinity Capillary Electrophoresis,Cyclodextrin Electrokinetic Chromatography and Capillary Electrophoresis-Mass Spectrometry

 Capillary electrophoresis (CE) has become a powerful tool for enantiomer separations during the last decade. Since 1993, the author has investigated enantiomer separations by affinity capillary electrophoresis (affinity CE) with some proteins and by cyclodextrin electrokinetic chromatography (CDEKC) with some charged cyclodextrins (CDs). Many successful enantiomer separations are demonstrated from our study in this review article. In the enantiomer separations by affinity CE, the deterioration of detection     

Synthesis and antitumor activity of novel pyrimidinyl pyrazole derivatives. II. Optimization of the phenylpiperazine moiety of 1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-3-phenylpiperazinyl-1-trans-propenes

A series of novel 3-substituted-1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-1-trans-propenes in order to improve the in vitro and in vivo activity of our prototype 3-[4-(3-chlorophenyl)-1-piperazinyl]-1-[5-methyl-1-(2-pyrimidinyl)-4-pyrazolyl]-1-trans-propene (2) were synthesized and evaluated by assays of growth inhibition against several tumor cell lines in vitro and antitumor activity against some tumor models when dosed both intraperitoneally and orally in vivo. Compounds 7a and 7e, the 3,5-difluorophenyl and 3,5-dichlorophenyl analogues of 2, respectively, showed significantly more potent cytotoxicity than 2 in vitro and potent antitumor activities without causing decrease of body temperature related to side effects.     

A new non-natural chiral auxiliary: design, synthesis, and resolution of 1-mesitylethylamine and its application in the asymmetric aza-Diels–Alder reaction

1-Mesitylethylamine was designed as a new non-natural chiral auxiliary. Racemic 1-mesitylethylamine could be synthesized in two steps from mesityl cyanide and could be resolved via separation of diastereomeric carbamates derived from (−)-menthyl chloroformate, followed by reduction with DIBAL and acidic hydrolysis. Imines, prepared from enantiopure 1-mesitylethylamine and aromatic aldehydes, reacted with Danishefsky’s diene in the presence of a Lewis acid to give cycloaddition products, 4-pyridone derivatives, with high diastereoselectivity.     

Synthesis of 5-acetyl-2-aminopyrrole C-deoxyribonucleoside

A novel C-deoxyribonucleoside bearing 2-aminopyrrole was synthesized. The C-glycosidation between deoxyribose and pyrrole ring was carried out using palladium-catalyzed Heck coupling in the presence of excess amount of lithium chloride as an additive. The synthesized aminopyrrole nucleoside is expected to become a promising counterpart of the artificial nucleoside pair.     

γ-Cyclodextrins possessing an azido group and a triisopropylbenzenesulfonyl group as useful synthetic and authentic intermediates for unsymmetrically functionalized derivatives

Seven isomers of cyclomaltooctaose (γ-cyclodextrin) whose C6s were unsymmetrically disubstituted with both an azido group and an arenesulfonyloxy group were prepared and each of them was isolated by reversed phase chromatography. The assignment of the modified positions in each regioisomers was unambiguously performed by chemical correlation with the authentic compounds and chemical conversion to the 3,6-anhydro derivatives followed by high-resolution 2D-¹H NMR (COSY, TOCSY, and HOHAHA) analyses. The compounds are versatile synthetic and authentic intermediates to prepare sophisticated derivatives with two different functionalities at desired positions on the molecule for supramolecular chemistry.