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首页> 外文期刊>Physical chemistry chemical physics: PCCP >Experimental and computational studies on ruthenium(ii) bis-diimine complexes of N,N-chelate ligands: the origin of changes in absorption spectra upon oxidation and reduction
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Experimental and computational studies on ruthenium(ii) bis-diimine complexes of N,N-chelate ligands: the origin of changes in absorption spectra upon oxidation and reduction

机译：N，N-螯合配体的钌（II）双二亚胺配合物的实验和计算研究：氧化和减少时吸收光谱的变化起源

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摘要

This work presents an interpretation of the origin of changes in absorption spectra upon one-electron oxidation and reduction of two ruthenium polypyridyl complexes based on a combination of UV-Vis spectroelectrochemical experiments and theoretical calculations using the Gaussian 09 program. A bis-chelating ligand containing a p-bromobenzoylthiourea unit connected to 1,10-phenanthroline (phen-p-BrBT) has been prepared. Complexation of phen-p-BrBT to ruthenium bis-diimine centres, Ru(N-N)(2) [N-N = 2,2-bipyridine (bpy) or 1,10-phenanthroline (phen)], affords octahedral Ru(ii) tris-diimine complexes that are synthesised and structurally characterised. The two complexes exhibit similar MLCT bands and electronic energy levels owing to the similar electronic structures of the bpy and phen ligands. However, [Ru(phen)(2)(phen-p-BrBT)](2+) exhibits a slightly broader visible region MLCT (metal-to-ligand-charge transfer) band than [Ru(bpy)(2)(phen-p-BrBT)](2+) as expected from a slightly more delocalised -electron system in the phen diimine ligands. In addition, the * absorption in the UV is blue-shifted for [Ru(phen)(2)(phen-p-BrBT)](2+) relative to that for [Ru(bpy)(2)(phen-p-BrBT)](2+), because of greater stabilisation of the bpy HOMO relative to that of phen. The extra C-C bond in phen produces greater delocalisation of electron density leading to a blue-shift in the * transition. The MLCT band is blue-shifted and diminished in intensity upon oxidation due to stabilisation of the Ru d-orbitals by removal of one electron. A new broad absorption band appears in the UV region upon reduction. The new transition is attributed to a blue-shift of the first MLCT transition for [Ru(bpy)(2)(phen-p-BrBT)](2+) and a red-shift of the second MLCT transition for [Ru(phen)(2)(phen-p-BrBT)](2+). The new transitions originate from destabilisation or stabilisation of the ligand LUMO orbitals relative to the Ru d-orbitals. A red-shift of the UV band in the initial complex also contributes to the new band produced upon reduction of [Ru(bpy)(2)(phen-p-BrBT)](2+). The new band does not involve an n(C?S) * transition. Although both complexes show subtle differences in behaviour, their spectral changes are distinct, and the origin of changes in their absorption spectra upon oxidation and reduction is successfully interpreted.
机译：该作品提出了一种在使用高斯09程序的UV-Vis光谱电化学实验和理论计算的组合基础上对一电子氧化和减少两种钌聚吡啶复合物的吸收光谱的变化起源的解释。制备了含有连接至1,10-菲咯啉（Phen-P-BBT）的双螯合配体的双螯合配体。将Phen-P-BRBT络合到钌双二嘧啶中心，Ru（NN）（2）[NN = 2,2-苯吡啶（BPY）或1,10-菲啉（Phen）]，提供八面体ru（ii）tris - 合成和结构表征的二亚胺复合物。由于BPY和Phen配体的类似电子结构，两种复合物表现出类似的MLCT带和电子能级。但是，[Ru（phen）（2）（2）（phen-p-BRBT）]（2+）表现出略宽的可见区域MLCT（金属 - 己配体 - 电荷转移）频带，而不是[Ru（BPY）（2）（ Phen-P-BRBT）]（2+）如预期的稍微划分的 - 电气系统中的预期在菲亚胺配体中。此外，相对于[ru（bpy）（2）（phen-p.]（phen-p）（phen-p -BrBT）]（2+），因为BPY HOMO相对于苯的更大稳定。额外的C-C键在苯中产生更大的电子密度的逐渐扩展，导致*过渡中的蓝色偏移。由于通过除去一个电子，MLCT带在氧化时，在氧化时的强度为蓝色移位和减小。减少时，紫外地区出现了一种新的宽吸收带。新的过渡归因于[Ru（BPY）（2）（2）（Phen-P-BRBT）]（2+）的第一MLCT转变的蓝偏移，以及[Ru（ Phen）（2）（Phen-P-BRBT）]（2+）。新的过渡源于相对于Ru D-轨道的配体Lumo轨道的不稳定或稳定性。初始复合物中的UV带的红色偏移也有助于在减少[Ru（BPY）（2）（2）（Phen-P-BRBT）]（2+）时产生的新带。新频段不涉及n（c？s）*转换。虽然两种复合物都显示出对行为的微妙差异，但它们的光谱变化是明显的，并且成功地解释了氧化和减少时吸收光谱的变化的起源。

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    San Tan Siew; Yanagisawa Susumu; Inagaki Kouji; Kassim Mohammad B.; Morikawa Yoshitada;

  • 作者单位

    Osaka Univ Grad Sch Engn Dept Precis Sci &

    Technol 2-1 Yamada Oka Suita Osaka 5650871 Japan;

    Univ Ryukyus Fac Sci Dept Phys &

    Earth Sci 1 Senbaru Nishihara Okinawa 9030213 Japan;

    Osaka Univ Grad Sch Engn Dept Precis Sci &

    Technol 2-1 Yamada Oka Suita Osaka 5650871 Japan;

    Osaka Univ Grad Sch Engn Dept Precis Sci &

    Technol 2-1 Yamada Oka Suita Osaka 5650871 Japan;

    Osaka Univ Grad Sch Engn Dept Precis Sci &

    Technol 2-1 Yamada Oka Suita Osaka 5650871 Japan;

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  • 正文语种 eng
  • 中图分类 物理学;化学;
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