σ-Pt-BODIPY Complexes with Platinum Attachment to Carbon Atoms C2 or C3: Spectroscopic, Structural, and (Spectro)Electrochemical Studies and Photocatalysis
σ-Pt-BODIPY Complexes with Platinum Attachment to Carbon Atoms C2 or C3: Spectroscopic, Structural, and (Spectro)Electrochemical Studies and Photocatalysis
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DOI：
10.1021/acs.organomet.7b00806
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发表时间：
2018-01-22
期刊：
影响因子：
2.8
通讯作者：
Winter, Rainer F.
中科院分区：
文献类型：
--
作者：
Irmler, Peter;Winter, Rainer F.
在这项工作中，我们讨论了通式反式-Pt(bodipy)I(PEt3)(2)的五种新配合物，其中不同取代的bodipy染料通过与吡咯碳原子C2或C3的直接Pt-C西格玛键连接到配位中心。我们还报告了氧化加成步骤的可分离中间体，其中 bodipy 与 cis-Pt(0)(PEt3)(2) 部分以 eta(2) 键合。新配合物、内消旋铂类似物 8-Pt 和母体染料之间的比较表明，铂附着位点影响光谱、光物理、电化学和电子特性。与 8-Pt 相比，吸收带和发射带相对于母体染料发生红移。 2-铂化 bodipy 染料 2-Pt-6H、2-Pt-6I、2-Pt-Mes-6I 和 2-Pt-6Et 表现出双重荧光和 NIR 磷光发射，量子产率较低，而 3-Pt 仅通过荧光发射 (Phi(Fl) = 52.7%）。该配合物是光化学 O-1(2) 生产的适度有效的敏化剂，但优于亚甲蓝。如循环伏安法所示，它们还经历一种可逆的单电子还原和氧化。相对于母体染料，半波电位阴极移动 340-510 mV。通过 UV/vis/NIR 和 EPR 光谱以及 TD-DFT 计算生成并研究了单电子还原形式和一些单电子氧化形式。它们的光谱与其他 bodipy 染料的单电子还原或氧化形式的光谱相似，以及结构丰富的 EPR 光谱和接近 g(e) 的 g 值证明了相关前沿 MO 的主要 bodipy 特征。
In this work we discuss five new complexes with the general formula trans-Pt(bodipy)I(PEt3)(2), where differently substituted bodipy dyes attach to the coordination center via a direct Pt-C sigma-bond to the pyrrolic carbon atom C2 or C3. We also report an isolable intermediate of the oxidative addition step where the bodipy is eta(2)-bonded to the cis-Pt(0)(PEt3)(2) moiety. Comparison between the new complexes, meso-platinated analogue 8-Pt, and the parent dyes reveals that the site of platinum attachment influences the spectroscopic, photophysical, electrochemical, and electronic properties. In contrast to 8-Pt, absorption and emission bands are red-shifted with respect to the parent dyes. 2-Platinated bodipy dyes 2-Pt-6H, 2-Pt-6I, 2-Pt-Mes-6I, and 2-Pt-6Et exhibit dual fluorescence and NIR phosphorescence emissions, with low quantum yields, whereas 3-Pt emits solely by fluorescence (Phi(Fl) = 52.7%). The complexes are modestly efficient sensitizers for photochemical O-1(2) production but outperform methylene blue. They also undergo one reversible one-electron reduction and oxidation as indicated by cyclic voltammetry. Half-wave potentials are cathodically shifted by 340-510 mV with respect to the parent dyes. The one-electron reduced and some of the one-electron oxidized forms were generated and investigated by UV/vis/NIR and EPR spectroscopy as well as TD-DFT calculations. The similarity of their spectra to those of the one-electron reduced or oxidized forms of other bodipy dyes as well as the richly structured EPR spectra and g-values close to g(e) attest to a dominant bodipy character of the relevant frontier MOs.