Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, UK.
Dalton Trans. 2019 Nov 21;48(43):16426-16436. doi: 10.1039/c9dt03343b. Epub 2019 Oct 25.
Photolysis of trypto-CORM, fac-[Mn(tryp)(CO)(NCMe)] (tryp = tryptophanate) at 400 nm results in controlled CO-release which may be utilised to inhibit the growth of Escherichia coli (E. coli). An investigation into the fundamental processes which underpin the CO-release event is described. Time-dependent density functional theory (TD-DFT) indicates that irradiation at 400 nm results in LMCT from the indole group of the amino acid to orbitals based on the metal as well as the carbonyl and NCMe ligands. Ultra-fast time-resolved infra-red spectroscopy (TRIR) demonstrates that in NCMe solution, photolysis (400 nm) results in loss of CO in under 3 ps with the sequential generation of three new states with two carbonyl ligands and a coordinated tryptophanate. The first species is assigned to vibrationally hot [Mn(tryp)(CO)(NCMe)] which undergoes cooling to give the complex in its v = 0 state. This triplet state then undergoes solvation (τ≈ 20 ps) with a concomitant change in spin to give [Mn(tryp)(CO)(NCMe)] which persists for the remainder of the experiment (800 μs). These data indicate that following the initial photochemically induced loss of CO, any thermal CO loss is much slower. Related experiments with trypto-CORM in a mixture of DMSO and DO gave analogous data, indicating that this process also occurs in the medium used for the evaluation of biological properties.
在 400nm 处光解 trypto-CORM（fac-[Mn(tryp)(CO)(NCMe)]，tryp = 色氨酸酸盐）会导致受控的 CO 释放，这可用于抑制大肠杆菌（E.coli）的生长。本文描述了对支持 CO 释放事件的基本过程的研究。时变密度泛函理论（TD-DFT）表明，在 400nm 处的辐照会导致氨基酸的吲哚基团到基于金属以及羰基和 NCMe 配体的轨道的 LMCT。超快时间分辨红外光谱（TRIR）表明，在 NCMe 溶液中，光解（400nm）导致 CO 在 3ps 内损失，随后生成三个具有两个羰基配体和一个配位色氨酸酸盐的新状态。第一个物种被分配到振动热的[Mn(tryp)(CO)(NCMe)]，它经历冷却以给出处于 v=0 状态的复合物。然后，该三重态经历溶剂化（τ≈20ps），同时自旋发生变化，得到[Mn(tryp)(CO)(NCMe)]，该状态在实验的其余部分（800μs）中持续存在。这些数据表明，在初始光化学诱导的 CO 损失之后，任何热 CO 损失都要慢得多。在 DMSO 和 DO 的混合物中用 trypto-CORM 进行的相关实验给出了类似的数据，表明该过程也发生在用于评估生物学性质的介质中。
