Photochemical generation and kinetic studies of a putative porphyrin-ruthenium(V)-oxo species.
Photochemical generation and kinetic studies of a putative porphyrin-ruthenium(V)-oxo species.
复制标题
DOI：
10.1039/c4dt00649f
复制
发表时间：
2014-06-21
期刊：
影响因子：
--
通讯作者：
Newcomb M
中科院分区：
文献类型：
--
作者：
Zhang R;Vanover E;Luo W;Newcomb M
双卟啉-二钌(IV)μ-氧代二聚体的光歧化产生了卟啉-钌(III)物种和推定的卟啉-钌(V)-氧代物种，可以通过激光闪光光解方法实时检测和研究。根据其光谱和动力学行为确定，卟啉-钌(III) N-氧化物加合物的光解也形成相同的氧化瞬态。确定了 22 °C 下多种底物反应的二阶速率常数；速率常数的代表值为二苯甲醇的 kox = 6.6 × 103 M−1 s−1，苯乙烯的 kox = 2.5 × 103 M−1 s−1，环己烯的 kox = 1.8 × 103 M−1 s−1。假定的卟啉-钌(V)-氧代瞬态反应速度比相应的反式二氧钌(VI)-氧代卟啉快5-6个数量级，并且本工作中获得的速率常数与咔咯-铁(V)-氧代衍生物的速率常数相似。与其他卟啉-金属-氧中间体相比，光化学生成的钌-氧物种的高反应性表明它是真正的钌(V)-氧物种。
Photo-disproportionation of a bis-porphyrin-diruthenium(IV) μ-oxo dimer gave a porphyrin-ruthenium(III) species and a putative poprhyrin-ruthenium(V)-oxo species that can be detected and studied in real time via laser flash photolysis methods. As determined by its spectral and kinetic behavior, the same oxo transient was also formed by photolysis of a porphyrin-ruthenium(III) N-oxide adduct. Second-order rate constants for reactions with several substrates at 22 °C were determined; representative values of rate constants were kox = 6.6 × 103 M−1 s−1 for diphenylmethanol, kox = 2.5 × 103 M−1 s−1 for styrene, and kox = 1.8 × 103 M−1 s−1 for cyclohexene. The putative porphyrin-ruthenium(V)-oxo transient reacted 5–6 orders of magnitude faster than the corresponding trans-dioxoruthenium(VI)-oxo porphyrins, and the rate constants obtained in this work were similar to those of corrole-iron(V)-oxo derivative. The high reactivity for the photochemically generated ruthenium-oxo species in comparison to other poprhyrin-metal-oxo intermediates suggests it is a true ruthenium(V)-oxo species.
登录
查看更多内容
影响因子：
15
作者：
Pan Z;Wang Q;Sheng X;Horner JH;Newcomb M
通讯作者：
Newcomb M
影响因子：
15
作者：
PETERSON, MW;RIVERS, DS;RICHMAN, RM
通讯作者：
RICHMAN, RM
影响因子：
15
作者：
Cho, Kevin;Leeladee, Pannee;Goldberg, David P.
通讯作者：
Goldberg, David P.
影响因子：
15
作者：
Harischandra, DN;Zhang, R;Newcomb, M
通讯作者：
Newcomb, M
影响因子：
4.6
作者：
Pan, Zhengzheng;Zhang, Rui;Newcomb, Martin
通讯作者：
Newcomb, Martin