Aggregation Effect on the Luminescence Properties of Phenylbipyridine Pt(II) Acetylide Complexes. A Theoretical Prediction with Experimental Evidence

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• 作者：Anissa Amar ; Hac猫ne Meghezzi ; Julien Boixel ; Hubert Le Bozec ; V茅ronique Guerchais ; Denis Jacquemin ; Abdou Boucekkine
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：August 14, 2014
• 年：2014
• 卷：118
• 期：32
• 页码：6278-6286
• 全文大小：410K
• ISSN：1520-5215

文摘

We report a combined theoretical and experimental study of both the structural and optical properties of phosphorescent cyclometalated square-planar (phenylbipyridyl)platinum(II) acetylide complexes, namely (Pt(tBu₂-膱N̂N)(C鈮鈥擯h)] and (Pt(hex₂-膱N̂N)(C鈮鈥攖hienyl)] that exhibit, at high concentrations, an additional emission band at longer wavelength. The geometry optimizations of both the ground and the lowest triplet excited states of the considered monomers and different possible dimers have been performed in solution using several density functional theory (DFT) functionals corrected for dispersion effects. For the dimers, which are shown to exhibit a head-to-tail configuration, a significant shortening of the Pt路路路Pt distance, compared to that in the ground state, is observed in the first triplet state. Moreover, we show that trimeric species are highly improbable in solution. The UV鈥搗isible absorption spectra of the complexes are well rationalized using a vertical time-dependent DFT (TD-DFT) protocol relying on a global hybrid exchange鈥揷orrelation functional. Finally, the new emission band at high concentration of the complexes can be assigned to a metal鈥搈etal to ligand charge transfer excited state (³MMLCT).