Yempally Veeranna, Moncho Salvador, Hasanayn Faraj, Fan Wai Yip, Brothers Edward N, Bengali Ashfaq A
Department of Chemistry, Texas A&M University at Qatar , Doha, Qatar.
Department of Chemistry, American University of Beirut , Beirut, Lebanon.
Inorg Chem. 2017 Sep 18;56(18):11244-11253. doi: 10.1021/acs.inorgchem.7b01543. Epub 2017 Sep 5.
The photochemistry of two Mn(bpy)(CO)X complexes (X = PhCC, Br) has been studied in the coordinating solvents THF (terahydrofuran) and MeCN (acetonitrile) employing time-resolved infrared spectroscopy. The two complexes are found to exhibit strikingly different photoreactivities and solvent dependencies. In MeCN, photolysis of 1-(CO)(Br) [1 = Mn(bpy)(CO)] affords the ionic complex [1-(MeCN)]Br as a final product. In contrast, photolysis of 1-(CO)(CCPh) in MeCN results in facial to meridional isomerization of the parent complex. When THF is used as solvent, photolysis results in facial to meridional isomerization in both complexes, though the isomerization rate is larger for X = Br. Pronounced differences are also observed in the photosubstitution chemistry of the two complexes where both the rate of MeCN exchange from 1-(MeCN)(X) by THFA (tetrahydrofurfurylamine) and the nature of the intermediates generated in the reaction are dependent upon X. DFT calculations are used to support analysis of some of the experiments.
利用时间分辨红外光谱，在配位溶剂四氢呋喃（THF）和乙腈（MeCN）中研究了两种Mn(bpy)(CO)X配合物（X = PhCC、Br）的光化学性质。发现这两种配合物表现出显著不同的光反应活性和溶剂依赖性。在乙腈中，1-(CO)(Br) [1 = Mn(bpy)(CO)] 的光解产生离子配合物 [1-(MeCN)]Br作为最终产物。相比之下，1-(CO)(CCPh) 在乙腈中的光解导致母体配合物从面式到经式的异构化。当使用四氢呋喃作为溶剂时，两种配合物的光解均导致从面式到经式的异构化，尽管对于X = Br，异构化速率更大。在两种配合物的光取代化学中也观察到明显差异，其中从1-(MeCN)(X) 与四氢糠胺（THFA）进行乙腈交换的速率以及反应中生成的中间体的性质均取决于X。密度泛函理论（DFT）计算用于支持对一些实验的分析。
