排序方式: 共有25条查询结果,搜索用时 15 毫秒
1.
在前文工作的基础上,结合MNDO/EHMO分子轨道方法和自然杂化轨道方法,具体计算了CC键和CP键的核自旋偶合常数.计算结果表明,1JCC和1JCP主要由成键原子的轨道杂化作用和键极性这两种结构因素所决定.为从简单价键理论角度解释和计算1JCC和1JCP值提供了简便直观的方法. 相似文献
2.
Electrocatalytic Carbon Dioxide Reduction by Using Cationic Pentamethylcyclopentadienyl–Iridium Complexes with Unsymmetrically Substituted Bipyridine Ligands
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Fanni D. Sypaseuth Corinna Matlachowski Manuela Weber Dr. Matthias Schwalbe Prof. Dr. C. Christoph Tzschucke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(17):6564-6571
Eight [Ir(bpy)Cp*Cl]+‐type complexes (bpy= bipyridine, Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) containing differently substituted bipyridine ligands were synthesized and characterized. Cyclic voltammetry (CV) of the complexes in Ar‐saturated acetonitrile solutions showed that the redox behavior of the complexes could be fine tuned by the electronic properties of the substituted bipyridine ligands. Further CV in CO2‐saturated MeCN/H2O (9:1, v/v) solutions showed catalytic currents for CO2 reduction. In controlled potential electrolysis experiments (MeCN/MeOH (1:1, v/v), Eapp=?1.80 V vs Ag/AgCl), all of the complexes showed moderate activity in the electrocatalytic reduction of CO2 with good stability over at least 15 hours. This electrocatalytic process was selective toward formic acid, with only traces of dihydrogen or carbon monoxide and occasionally formaldehyde as byproducts. However, the turnover frequencies and current efficiencies were quite low. No direct correlation between the redox potentials of the complexes and their catalytic activity was observed. 相似文献
3.
4.
[reaction: see text] The synthesis of arylboronic acids and aryl trifluoroborates in a one-pot sequence by Ir-catalyzed borylation of arenes is reported. To prepare the arylboronic acids, the Ir-catalyzed borylation is followed by oxidative cleavage of the boronic ester with NaIO4. To prepare the aryltrifluoroborate, the Ir-catalyzed borylation is followed by displacement of pinacol by KHF2. These two-step sequences give products that are more reactive toward subsequent chemistry than the initially formed pinacol boronates. 相似文献
5.
6.
Michalek F Horn J Tzschucke CC Bannwarth W 《Combinatorial chemistry & high throughput screening》2003,6(7):729-740
Supported catalysts have become valuable tools for simplified product isolation and catalyst recycling. The common method is covalent attachment to a solid support. An alternative strategy is to immobilize catalysts by non-covalent bonding through hydrogen bridges, ionic, hydrophobic or fluorous interactions. Compared to covalent attachment, such non-covalent approaches increase the flexibility in the choice of the support-material, reaction conditions and work-up strategies. Numerous catalytic reactions employing one of these non-covalent fixation strategies have meanwhile appeared in the literature. 相似文献
7.
8.
9.
10.
Vasyl Andrushko Dominik Schwinn CarlChristoph Tzschucke Florian Michalek Joachim Horn Christian Mssner Willi Bannwarth 《Helvetica chimica acta》2005,88(5):936-949
Unexpectedly high retention times were obtained in HPLC investigations for compounds equipped with (C8F17CH2CH2)3Si tags on C8F17‐modified silica gel (Fig. 4). Hence, these tags have a high potential for the noncovalent immobilization of catalysts to be applied in organic solvents, allowing for an easy separation and re‐use of the catalyst by filtration and reapplication. The tris(perfluoroalkyl)silyl tag could be incorporated in a straightforward manner into ligands as demonstrated by the synthesis of several prominent classes of ligands (Schemes 4–6). 相似文献