Garoni Eleonora, Boixel Julien, Dorcet Vincent, Roisnel Thierry, Roberto Dominique, Jacquemin Denis, Guerchais Véronique
Institut des Sciences Chimiques de Rennes, UMR CNRS 6226, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France.
Dalton Trans. 2017 Dec 19;47(1):224-232. doi: 10.1039/c7dt03695g.
The synthesis, spectroscopic and theoretical characterizations of dinuclear Pt(ii) complexes where the two chromophoric units are connected though a polyether chain via either the central benzene ring of the tridentate ligand dpyb (Pt-2), or the phenylacetylide ligand (Pt-3), are described. The spacer, which contains four oxyethylene -CHCHO- units, is flexible and long enough to allow a self-association of the Pt units by folding, as shown by DFT calculations. Comparison of the photophysical properties of the dinuclear complex Pt-2 with those of the mononuclear complex Pt-1, used as reference, demonstrates the key role played by the linker group in the interaction processes. In addition, the emission of complex Pt-2 was found to be affected by the temperature, nature of the solvent, and cation coordination as evidenced by luminescence and H NMR studies. The interacting processes are highly dependent on the solvent polarity that controls the - extended vs folded - arrangement and, consequently, induces solvatochromic shifts. This unique photophysical behavior of Pt-2 allows the modulation of the emission from green to deep-red (up to 125 nm) over the visible part of the spectrum. By contrast, complex Pt-3 has a high propensity to form a red-shifted intense emissive excimer. DFT and TD-DFT investigations of the excimers in Pt-2 and Pt-3 consistently show a much stronger interaction in the latter complex.
描述了双核Pt(ii)配合物的合成、光谱和理论表征，其中两个发色单元通过聚醚链经由三齿配体dpyb的中心苯环（Pt-2）或苯乙炔配体（Pt-3）相连。间隔基包含四个氧乙烯-CHCHO-单元，具有柔性且足够长，以允许通过折叠实现Pt单元的自缔合，如密度泛函理论（DFT）计算所示。将双核配合物Pt-2与用作参考的单核配合物Pt-1的光物理性质进行比较，证明了连接基团在相互作用过程中所起的关键作用。此外，发光和核磁共振氢谱（H NMR）研究表明，配合物Pt-2的发射受温度、溶剂性质和阳离子配位的影响。相互作用过程高度依赖于控制伸展与折叠排列的溶剂极性，因此会引起溶剂化变色位移。Pt-2这种独特的光物理行为使得其发射在光谱的可见光部分可从绿色调制到深红色（高达125 nm）。相比之下，配合物Pt-3极易形成红移的强发射准分子。对Pt-2和Pt-3中准分子的DFT和含时密度泛函理论（TD-DFT）研究一致表明，后一种配合物中的相互作用要强得多。
