Directing energy transfer in Pt(bodipy)(mercaptopyrene) dyads.
Directing energy transfer in Pt(bodipy)(mercaptopyrene) dyads.
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DOI：
10.1039/c9dt01737b
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发表时间：
2019-08
影响因子：
4
通讯作者：
P. Irmler;Franciska S. Gogesch;André Mang;M. Bodensteiner;Christopher B. Larsen;O. Wenger;R. Winter
中科院分区：
文献类型：
--
作者：
P. Irmler;Franciska S. Gogesch;André Mang;M. Bodensteiner;Christopher B. Larsen;O. Wenger;R. Winter
我们报道了在Pt(PEt3)2片段上结合4,4-二氟-4-硼-3a，4 -二氮-s-茚二烯（bodipy， BDP）和巯基芘（SPyr）染料配体的三个二元体的光物理性质。染料与Pt离子的σ-键作用通过外重原子效应促进了体系间的交叉。从富电子巯基芘到接受电子的BDP配体（PB-CT）的电荷转移的高效ISC耦合产生了多种（潜在的）发射态。这最终导致了BPtSPyr和BPtSPyrSPtB的单核和双核配合物的四种不同的释放，这些配合物具有未取代的BDP配体和末端1-巯基芘或桥接芘-1,6-二硫代酸配体。因此，在流体溶液中，从3PB-CT状态观察到724 nm的近红外发射，量子产率高达15%。激发到基于bdp的1π *或基于芘的1π *波段，还会触发以bdp为中心的1π *和3π *态的荧光和磷光发射。在冷冻溶液中，在77 K时，芘配体的磷光成为主要的发射通道，而PB-CT则不存在。KBPtSPyr中BDP配体的烷基化将所有激发能转化为KBDP配体的荧光和磷光发射。通过吸收和发射光谱、瞬态吸收光谱、电化学和紫外/可见/近红外光谱电化学测量以及量子化学计算来探测各种激发态和失活级联的分配。我们的结论进一步证实了合适的参考化合物的援助，只包含一个发色团。所有二联体都是三重态敏化剂，能够产生单线态氧。
We report on the photophysical properties of three dyads that combine a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (bodipy, BDP) and a mercaptopyrene (SPyr) dye ligand at a Pt(PEt3)2 fragment. σ-Bonding of the dyes to the Pt ion promotes intersystem crossing (ISC) via the external heavy atom effect. The coupling of efficient ISC with charge-transfer from the electron-rich mercaptopyrene to the electron-accepting BDP ligand (PB-CT) gives rise to a multitude of (potentially) emissive states. This culminates in the presence of four different emissions for the mono- and dinuclear complexes BPtSPyr and BPtSPyrSPtB with an unsubstituted BDP ligand and either a terminal 1-mercaptopyrene or a bridging pyrene-1,6-dithiolate ligand. Thus, in fluid solution, near IR emission at 724 nm from the 3PB-CT state is observed with a quantum yield of up to 15%. Excitation into the BDP-based 1ππ* or the pyrene-based 1ππ* band additionally trigger fluorescence and phosphorescence emissions from the BDP-centred 1ππ* and 3ππ* states. In frozen solution, at 77 K, phosphorescence from the pyrene ligand becomes the prominent emission channel, while PB-CT emission is absent. Alkylation of the BDP ligand in KBPtSPyr funnels all excitation energy into fluorescence and phosphorescence emissions from the KBDP ligand. The assignments of the various excited states and the deactivation cascades were probed by absorption and emission spectroscopy, transient absorption spectroscopy, electrochemical and UV/Vis/NIR spectroelectrochemical measurements, and by quantum chemical calculations. Our conclusions are further corroborated with the aid of suitable reference compounds comprising of just one chromophore. All dyads are triplet sensitizers and are able to generate singlet oxygen.