Marked Stabilization of Redox States and Enhanced Catalytic Activity in Galactose Oxidase Models Based on Transition Metal <i>S</i>-Methylisothiosemicarbazonates with −SR Group in Ortho Position to the Phenolic Oxygen
作者:Vladimir B. Arion、Sonja Platzer、Peter Rapta、Peter Machata、Martin Breza、Daniel Vegh、Lothar Dunsch、Joshua Telser、Sergiu Shova、Tatiana C. O. Mac Leod、Armando J. L. Pombeiro
DOI:10.1021/ic4004966
日期:2013.7.1
in CHCl3 with HCl(g) afforded H2L1. The latter reacts with Zn(OAc)2·2H2O with formation of ZnL1. The effect of −SR groups and metal ion identity on stabilization of phenoxyl radicalsgenerated electrochemically was studied in detail. A marked stabilization of phenoxyl radical was observed in one-electron-oxidized complexes [ML2]+ (M = Ni, Cu) at room temperature, as demonstrated by cyclic voltammetry
5-叔丁基-2-羟基-3-甲基硫烷基苯甲醛S-甲基异硫半脲与5-叔丁基-2-羟基-3-苯基硫烷基苯甲醛S-甲基异硫半脲与戊烷-2,4-二酮(Hacac)和原甲酸三乙酯的反应M(acac)2作为模板源在107°C下的存在提供了M II L 1和M II L 2类型的金属配合物,其中M = Ni和Cu,带有带有硫代甲基的新席夫碱配体(H 2 L 1)和/或苯硫基(H 2 L 2)在酚部分的邻位。将NiL 1在CHCl 3中用HCl(g)脱金属,得到H 2 L 1。后者与Zn(OAc)2 ·2H 2 O反应形成ZnL 1。详细研究了-SR基团和金属离子同一性对电化学生成的苯氧基自由基稳定性的影响。如循环伏安法,EPR光谱和UV-vis-NIR测量所证明的,在室温下,单电子氧化的络合物[ML 2 ] +(M = Ni,Cu)中观察到苯氧基的显着稳定。在溶液中,氧化的CuL 2和NiL 2表现出强烈
An unexpected destabilisation of copper(II) phenoxyl radical species by steric protection
作者:Isabelle Sylvestre、Joanna Wolowska、Eric J.L. McInnes、Colin A. Kilner、Malcolm A. Halcrow
DOI:10.1016/j.ica.2004.11.004
日期:2005.3
The complexes [CuL(Tp(Ph))] (HL = 5-tertbutylsalicylaldehyde, 5-tertbutyl-3-methylsulfanylsalicylaldehyde or 5-tertbutyl-3-phenylsulfanylsalicylaldehyde; [Tp(Ph)](-) = tris-3-phenylpyrazolyl}hydridoborate) have been prepared, and adopt square-pyramidal coordination geometries. Each compound exhibits a ligand-based oxidation in CH2Cl2 that is chemically reversible by voltammetry. However, Coulometric determinations showed that the resultant phenoxyl radical products decomposed rapidly at low temperatures in bulk solution. This instability may reflect intramolecular steric repulsions between the phenoxide tertbutyl substituents, and a pyrazolylborate phenyl group. These results contrast with a previously reported analogous compound, bearing a 5-methyl-3-methylsulfanylsalicylaldehydato ligand, which yields a phenoxyl radical oxidation product that is stable for hours under the same conditions. (c) 2004 Elsevier B.V. All rights reserved.
作者:Isabelle Sylvestre、Colin A. Kilner、Malcolm A. Halcrow
DOI:10.1107/s0108270105007675
日期:2005.5.15
The title compound, C23H24N4OS, contains a highly asymmetric bifurcated intramolecular hydrogen bond between the hydroxy group and two pyrazole N atoms. The compound associates into centrosymmetric dimers in the crystal through two unique C-H center dot center dot center dot pi interactions, which are in turn linked into a (6,3)-network through an additional intermolecular C-H center dot center dot center dot N hydrogen bond.
Galactose Oxidase Model Complexes: Catalytic Reactivities
作者:Yadong Wang、T. D. P. Stack
DOI:10.1021/ja9621354
日期:1996.1.1
Copper(ii) complexes of thioether-substituted salcyen and salcyan derivatives and their silver(i) adducts
作者:Isabelle Sylvestre、Joanna Wolowska、Colin A. Kilner、Eric J. L. McInnes、Malcolm A. Halcrow
DOI:10.1039/b505972k
日期:——
from 5-tert-butyl-2-hydroxybenzaldehyde. The complexes [CuL] (L2− = [L1]2−–[L6]2−) bearing sulfanyl substituents each show two distinct voltammetric ligand-based oxidations under the same conditions, the first of which is chemically reversible. The first oxidation product is much longer lived by coulometry for the salcyen than for the salcyan ligand complexes, despite the latter having a substantially
据报道有新的合成方法 5-叔丁基-2-羟基-3-甲基硫烷基苯甲醛, 5-叔丁基-2-羟基-3-苯基硫烷基苯甲醛以及水杨酸(H 2 L 1 –H 2 L 3)和水青色(H 2 L 4 –H 2 L 6)型配体 从这些派生 醛类 和从 5-叔丁基-2-羟基苯甲醛。含[CuL](L 2− = [L 1 ] 2− – [L 6 ] 2−)的配合物硫烷基 每个取代基显示两个不同的伏安 配体相同条件下的碱式氧化,第一个是化学可逆的。第一种氧化产物的寿命更长库仑法 水杨酸而不是蓝绿色 配体配合物,尽管后者具有明显较低的氧化电位。所有的生命配体 该系统中的氧化产物比衍生自类似化合物的氧化产物小得多 3,5-二(叔丁基)-2-羟基苯甲醛(Dalton Trans。,2004,2662)。尝试了化学氧化希夫碱使用AgBF 4的化合物生成稳定的银(I)加合物。一种这样的化合物的晶体结构表明,Ag原子被这两种化合物以稍微弯曲的几何形状配位配体