Catalytic catechol oxidation by copper complexes: development of a structure–activity relationship
作者:Erica C. M. Ording-Wenker、Maxime A. Siegler、Martin Lutz、Elisabeth Bouwman
DOI:10.1039/c5dt01041a
日期:——
High activity for the catalytic oxidation of 3,5-di-tert-butylcatechol was achieved with complexes of ligands that stabilize the biomimetic CuII μ-thiolate complex, hinting at a similarity with the required Cu-oxo intermediates.
Aerobic Oxidative Coupling of 2-Naphthol Derivatives Catalyzed by a Hexanuclear Bis(μ-hydroxo)copper(II) Catalyst
作者:Yedukondalu Meesala、Hsyueh-Liang Wu、Bommisetti Koteswararao、Ting-Shen Kuo、Way-Zen Lee
DOI:10.1021/om500403k
日期:2014.9.8
the three dicopper cores are linked by the dinucleating ligand between each pair of adjacent dicopper cores. Importantly, aerobicoxidative coupling of 2,4-di-tert-butylphenol, 2-naphthol, and six 2-naphthol derivatives was achieved in 33–96% yield using complex 1 as a catalyst.
合成了具有双核配体N,N,N,的新型六核双(μ-羟基)铜(II)络合物[ L 3(Cu 2(μ-OH)2)3 ](ClO 4)6(1)。ñ -四(吡啶-2-基甲基) -米二甲苯二胺(大号)。配合物1具有X射线晶体学和固态磁化率以及溶液中的UV-vis和电子顺磁共振波谱的全部特征。1的分子结构拥有三个双铜芯,其中两个铜中心被两个氢氧化物基团桥接,并以2.8852(15)到2.8937(10)Å之间的距离分隔。另外,三个双铜芯通过每对相邻的双铜芯之间的双核配体连接。重要的是,使用配合物1作为催化剂,可实现2,4-二叔丁基苯酚,2-萘酚和6种2-萘酚衍生物的好氧氧化偶联,收率33-96%。
Dinuclear Zn<sup>2+</sup>complexes in the hydrolysis of the phosphodiester linkage in a diribonucleoside monophosphate diester
Dizinc complexes that were formed from 2 ∶ 1 mixtures of Zn(NO3)2 and dinucleating ligands TPHP (1), TPmX (2) or TPpX (3) in aqueous solutions efficiently hydrolyzed diribonucleoside monophosphate diesters (NpN) under mild conditions. The dinucleating ligand affected the structure of the aquo-hydroxo-dizinc core, resulting in different characteristics in the catalytic activities towards NpN cleavage. The pH-rate profile of ApA cleavage in the presence of (Zn2+)2-1 was sigmoidal, whereas those of (Zn2+)2-2 and (Zn2+)2-3 were bell-shaped. The pH titration study indicated that (Zn2+)2-1 dissociates only one aquo proton (up to pH 12), whereas (Zn2+)2-2 dissociates three aquo protons (up to pH 10.7). The observed differences in the pH-rate profile are attributable to the various distributions of the monohydroxo-dizinc species, which are responsible for NpN cleavage. As compared to that using (Zn2+)2-1, the NpN cleavage using (Zn2+)2-2 showed a greater rate constant, with a higher product ratio of 3′-NMP/2′-NMP. The saturation behaviors of the rate, with regard to the concentration of NpN, were analyzed by Michaelis–Menten type kinetics. Although the binding of (Zn2+)2-2 to ApA was weaker than that of (Zn2+)2-1, (Zn2+)2-2 showed a greater kcat value than (Zn2+)2-1, resulting in higher ApA cleavage activity of the former.
The rate of hydrolysis of an RNA dimer, uridylyl(3′5′)uridine (UpU), promoted by dinuclear Zn complexes resulting from a series of ligands with differently spaced Zn ion binding sites, was examined. Although the ligands in the present study have in common two di-2-pyridylmethylamino moieties as the Zn binding sites, the activities of these ligands toward the hydrolysis were quite different. Our results
A highly sensitive gold nanoparticle-based colorimetric probe for pyrophosphate using a competition assay approach
作者:Sudeok Kim、Min Sik Eom、Seung Kyung Kim、Seong Hyeok Seo、Min Su Han
DOI:10.1039/c2cc37379c
日期:——
In this study, a mixture of [Zn2(1,3-bis[bis(2-pyridylmethyl)aminomethyl]benzene)]4+ ([Zn2(BBPAB)]4+) and 11-mercaptoundecylphosphoric acid functionalized gold nanoparticles (Phos-AuNPs) is shown to be a highly sensitive colorimetric probe that can easily detect pyrophosphate (PPi) at less than 200 nM with the naked eye.