• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Transformation of a Cp~*–Iridium(III) Precatalyst for Water Oxidation when Exposed to Oxidative Stress
【24h】

Transformation of a Cp~*–Iridium(III) Precatalyst for Water Oxidation when Exposed to Oxidative Stress

机译：暴露于氧化胁迫下水氧化的Cp〜*-铱（III）预催化剂的转化

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The reaction of [Cp*Ir(bzpy)NO_3] (1; bzpy=2-benzoylpyridine, Cp~*=pentamethylcyclopentadienyl anion), a competent water-oxidation catalyst, with several oxidants (H_2O_2, NaIO_4, cerium ammonium nitrate (CAN)) was studied to intercept and characterize possible intermediates of the oxidative transformation. NMR spectroscopy and ESI-MS techniques provided evidence for the formation of many species that all had the intact Ir–bzpy moiety and a gradually more oxidized Cp~* ligand. Initially, an oxygen atom is trapped in between two carbon atoms of Cp~* and iridium, which gives an oxygen–Ir coordinated epoxide, whereas the remaining three carbon atoms of Cp~* are involved in a η~3 interaction with iridium (2a). Formal addition of H_2O to 2a or H_2O_2 to 1 leads to 2b, in which a double MeCOH functionalization of Cp~* is present with one MeCOH engaged in an interaction with iridium. The structure of 2b was unambiguously determined in the solid state and in solution by X-ray single-crystal diffractometry and advanced NMR spectroscopic techniques, respectively. Further oxidation led to the opening of Cp~* and transformation of the diol into a diketone with one carbonyl coordinated at the metal (2c). A η~3 interaction between the three non-oxygenated carbons of "ex-Cp~*" and iridium is also present in both 2b and 2c. Isolated 2b and mixtures of 2a–c species were tested in wateroxidation catalysis by using CAN as sacrificial oxidant. They showed substantially the same activity than 1 (turnover frequency values ranged from 9 to 14 min~(-1)).
机译：[Cp * Ir（bzpy）NO_3]（1; bzpy = 2-苯甲酰基吡啶，Cp〜* =五甲基环戊二烯基阴离子），一种有效的水氧化催化剂，与几种氧化剂（H_2O_2，NaIO_4，硝酸铈铵（CAN））的反应）被研究来拦截和表征氧化转化的可能中间体。 NMR光谱学和ESI-MS技术为许多物种的形成提供了证据，这些物种都具有完整的Ir-bzpy部分和逐渐氧化的Cp〜*配体。最初，氧原子被困在Cp〜*和铱的两个碳原子之间，形成氧-Ir配位环氧化物，而Cp〜*的其余三个碳原子与铱（2a ）。将H_2O正式加入2a或将H_2O_2正式加入1b会导致2b，其中Cp〜*的双MeCOH官能化存在，而一个MeCOH与铱相互作用。分别通过X射线单晶衍射法和先进的NMR光谱技术明确确定了固态和溶液中2b的结构。进一步的氧化导致Cp-*的打开，并使二醇转变为在金属（2c）上配位有一个羰基的二酮。 “ ex-Cp〜*”的三个非氧化碳与铱之间的η〜3相互作用也存在于2b和2c中。通过使用CAN作为牺牲氧化剂，在水氧化催化中测试了分离的2b和2a–c种类的混合物。他们显示出与1基本相同的活性（周转频率值范围为9到14 min〜（-1））。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号