Synthesis and photovoltaic properties of main chain polymeric metal complexes containing 1,10‐phenanthroline metal complexes conjugating alkyl fluorene or alkoxy benzene by C═C bridge for dye‐sensitized solar cells

Four main chain polymeric metal complexes (P1–P4) based on 1,10‐phenanthroline metal complexes via the Heck coupling have been synthesized and characterized by Fourier transform infrared spectroscopy, ¹H NMR, UV–Vis absorption, photoluminescence spectroscopy, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, elemental analysis, and cyclic voltammetry. To investigate their photovoltaic properties, the dye‐sensitized solar cells based on these polymers dyes are studied, under the illumination of AM 1.5G, 100 mW/cm². The study results show the four polymers exhibit good thermally stable and the solar cells based on them have good device performance, and the maximum power conversion efficiency is up to 0.735% for the solar cells based on P3 with a short‐circuit current (J_sc) of 1.68 mA/cm² and an open‐circuit voltage (V_oc) of 0.62 V. Copyright © 2012 John Wiley & Sons, Ltd.     

Studies on the Cationic Copolymerization of α-Pinene and Styrene with Complex SbCl3/AlCl3 Catalyst Systems. I. Effects of the Polymerization Conditions on the Copolymerization Products

Abstract

The copolymerization products of α-pinene and styrene were prepared with the compound catalyst system SbCl₃/AlCl₃ by changing the Sb/Al ratio, feeding monomer ratio, solvent, and polymerization temperature. The compositions of the copolymerization products were quantitatively characterized by the method of the combination of micro-ozonization and thin-layer chromatography in terms of the contents of the homopolymers and the copolymers containing high or low mole fractions of α-pinene, the yields of pure copolymer, and the monomer unit ratios (F ₁) of copolymers. The results show that it was easier to obtain the higher yield (up to 80%) of the pure copolymer with the complex catalyst system than with AlCl₃ alone. The F ₁ values could be controlled between 30 and 56% under the following polymerization conditions: Sb/Al  1/2, α-pinene/styrene  70%, and the conversion of styrene  90%.     

The split common fixed point problem for infinite families of total quasi-asymptotically nonexpansive operators

The main purpose in this paper is to introduce an original technique, namely, a specific way of choosing the indexes of the involved operators, by which a new iterative algorithm is developed for solving the split common fixed point problem for infinite families of total quasi-asymptotically nonexpansive operators and some strong and weak convergence theorems are established for this class of nonlinear operators in the framework of infinite-dimensional Hilbert spaces. The result is more applicable than those of other authors with related interest.     

Superresolution imaging of DNA tetrahedral nanostructures in cells by STED method with continuous wave lasers

DNA tetrahedral nanostructures are considered to be uew nanocarriers because they can be precisely controlled and hold excellent penetration ability to the cellular membrane. Although the DNA tetrahedral nanostructure is extensively studied in biology and medicine, its behavior in the cells with nanoscale resolution is not understood clearly. In this letter, we demonstrate superrcsolution fluorescence imaging of the distribution of DNA tetrahedral nanostructures in the cell with a simulated emission depletion （STED） microscope, which is built based on a conventional eonfocal microscope and can t）rovide a resolution of 70 nm.     

Tailorable PC71BM Isomers: Using the Most Prevalent Electron Acceptor to Obtain High‐Performance Polymer Solar Cells

Despite being widely used as electron acceptor in polymer solar cells, commercially available PC₇₁BM (phenyl‐C₇₁‐butyric acid methyl ester) usually has a “random” composition of mixed regioisomers or stereoisomers. Here PC₇₁BM has been isolated into three typical isomers, α‐, β₁‐ and β₂‐PC₇₁BM, to establish the isomer‐dependent photovoltaic performance on changing the ternary composition of α‐, β₁‐ and β₂‐PC₇₁BM. Mixing the isomers in a ratio of α/β₁/β₂=8:1:1 resulted in the best power conversion efficiency (PCE) of 7.67 % for the polymer solar cells with PTB7:PC₇₁BM as photoactive layer (PTB7=poly[[4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl][3‐fluoro‐2‐[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl]]). The three typical PC₇₁BM isomers, even though sharing similar LUMO energy levels and light absorption, render starkly different photovoltaic performances with average‐performing PCE of 1.28–7.44 % due to diverse self‐aggregation of individual or mixed PC₇₁BM isomers in the otherwise same polymer solar cells.     

Salt effect on molecular orientation at air/liquid methanol interface

The salt effects on molecular orientation at air/liquid methanol interface were investigated by the polarization-dependent sum frequency generation vibrational spectroscopy(SFG-VS). We clarified that the average tilting angle of the methyl group to be u = 308 58 at the air/pure methanol surface assuming a d-function orientational distribution. Upon the addition of 3 mol/L Na I, the methyl group tilts further away from the surface normal with a new u = 418 38. This orientational change does not explain the enhancement of the SFG-VS intensities when adding Na I, implying the number density of the methanol molecules with a net polar ordering in the surface region also changed with the Na I concentrations. These spectroscopic findings shed new light on the salt effects on the surfaces structures of the polar organic solutions. It was also shown that the accurate determination of the bulk refractive indices and Raman depolarization ratios for different salt concentrations is crucial to quantitatively interpret the SFG-VS data.     

A Porphyrin-Based Covalent Organic Framework for Metal-Free Photocatalytic Aerobic Oxidative Coupling of Amines

Imines are important intermediates in drug synthesis. Photocatalytic aerobic oxidative coupling of amines has been considered as a clean and promising way to produce imines and has attracted great attention. Herein, we designed and synthesized a novel two-dimensional porphyrin-based covalent organic framework (Por-BC-COF) which adopts an AA stacking mode with excellent crystallinity, high Brunauer–Emmett–Teller surface areas (1200 m² g⁻¹), wide light absorption range (200–1300 nm) and good stability in a variety of organic solvents. Por-BC-COF can be used as a metal-free heterogeneous photocatalyst for the photocatalytic oxidation of amines to imines under visible light and red light with a high yield (97 %). This work presents a novel and efficient COF photocatalyst in the application of light-driven organic synthesis.     

Quantitative study of cellular heterogeneity in doxorubicin uptake and its pharmacological effect on cancer cells

Cellular heterogeneity in doxorubicin (DOX) uptake and its relationship with pharmacological effect on cancer cells were quantitatively investigated for the first time. An in vitro experimental model was established by treating human leukemia K562 and breast cancer MCF‐7 cells with different schedules of DOX with or without surface P‐glycoprotein (P‐gp) inhibitor verapamil (VER). The cellular heterogeneity in DOX uptake was quantitatively examined by single‐cell analysis using capillary electrophoresis coupled with laser‐induced fluorescence detection. The corresponding cytotoxic effect was tested by cellular morphology, 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazolium and flow cytometry assays. The expression of cellular membrane surface P‐gp was determined by flow cytometry. Results showed that the cellular heterogeneity exists in DOX uptake. The single‐high DOX schedule leads to lower uptake heterogeneity and higher mean drug uptake. The cellular heterogeneity in DOX uptake was found to be negatively correlated with drug cytotoxicity and surface P‐gp expression, with r = ?0.7680 to ~ ?0.9587. VER reduces the cellular variation in DOX uptake, suggesting that surface P‐gp may be one of the causes of the cellular heterogeneity in DOX uptake. This research demonstrates the importance of quantitative study of cellular heterogeneity in drug uptake and its potential application in drug schedule design, response prediction and therapy modulation. Copyright © 2014 John Wiley & Sons, Ltd.