丁基罗丹明 B-铋钼杂多酸光度法测定铋

在硫酸介质及吐温存在下，丁基罗丹明Ｂ（ＢＲＢ）与铋钼杂多酸形成离子缔合物，缔合物的最大吸收波长位于６０６ｎｍ，表观摩尔吸光系数为１．７＊１０＾６Ｌ．同，铋质量浓度在０－０．２４μｇ／ｍＬ范围内服从比尔定律。缔合物至少稳定２４ｈ，其摩尔比为ｎ（Ｂｉ）：ｎ（Ｍｏ）：ｎ（ＢＲＢ）＝１：１２：４。考察了２０余种共存离子的影响，大多数常见元素不干扰。本法已用于矿样，合金中铋的测定。     

Poly(methacrylamide‐co‐2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) hydrogels: Investigation of pH‐ and temperature‐dependent swelling characteristics and their characterization

Novel poly(methacrylamide‐co‐2‐acrylamido‐2‐methyl‐ 1‐propanesulfonic acid) (poly(MAAm‐co‐AMPS)) hydrogels were synthesized by free radical polymerization of methacrylamide (MAAm) and 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) in deionized water at 60 °C by using ammonium peroxydisulfate (APS), N,N′‐methylenebisacrylamide (MBAAm) and N,N,N′,N′‐tetramethylethylenediamine (TEMED) as initiator, crosslinker, and activator, respectively. To investigate the effects of feed content on the pH‐ and temperature‐dependent swelling behavior of poly(MAAm‐co‐AMPS), molar ratio of MAAm to AMPS in feed was varied from 90/10 to 10/90. Structural characterization of gels was performed by Fourier transform infrared (FTIR) spectroscopy using attenuated total reflectance (ATR) technique. Thermal and morphological characterizations of gels were performed by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), respectively. Although an apparent pH‐sensitivity was not observed for the poly(MAAm‐co‐AMPS) gels during the swelling in different buffer solutions, their temperature‐sensitivity became more evident with the increase in AMPS content of copolymer. Thermal stability of poly(MAAm‐co‐AMPS) gels increased with MAAm content. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010     

Rhodium/olefin-catalyzed reaction of arylboronic acids with an α-acetamido acrylic ester: Mizoroki–Heck-type reaction versus asymmetric conjugate addition

In this paper we present our results concerning the rhodium/olefin-catalyzed reaction of arylboronic acids with an α-acetamido acrylic ester. With a chiral norbornadiene ligand rather low enantioselectivities (up to 21% ee) were obtained. Besides the expected conjugate adduct, we also observed the formation of a significant amount of Mizoroki–Heck-type product. The ratio of the conjugate adduct/Mizoroki–Heck product could be adjusted by a proper choice of the olefin ligand.     

Substituents Effects to the Electrochemical,and In Situ Spectroelectrochemical Behavior of Metallophthalocyanines: Electrocatalytic Application for Hydrogen Evolution Reaction

This study describes the effects of the number of fluoro substituents to the electrochemical, in situ spectroelectrochemical, and electrocatalytic activities of metallophthalocyanines for the hydrogen evolution reaction. Tuning of the number of fluoro groups shifts the redox processes and affects the aggregation tendencies of the complexes. An in situ electrocolorimetric method was applied to investigate the color of the electrogenerated anionic and cationic forms of the complexes. Cobalt phthalocyanines incorporated into Nafion film on a glassy carbon electrode decreases the overpotential of the working electrode for H⁺ reduction. The number and position of the electron withdrawing substituents and nature of the metal center change the electrocatalytic activities for the hydrogen evolution reaction in aqueous solutions.