科研之友
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摘要
To investigate possible through-space charge transfer transitions between a Pt(II) ion and a triarylborane unit, the two new nonconjugated molecules 1 and 2 have been synthesized and fully characterized. Compound 1 has a V-shaped geometry, while 2 has a U-shaped geometry. In 1 a BMes(2)Ar group and a ppy group (Mes = mesityl, ppy = phenylpyridine) are linked together by a SiPh(2) unit, while in 2 these groups are joined together by a 1,8-naphthyl linker. The crystal structures of 1 and 2 were determined by single-crystal X-ray diffraction analyses. Their cyclometalated compounds Pt-1 and Pt-2 with a Pt(acac) unit chelated to the ppy site have been synthesized. Computational and experimental examinations on the photophysical properties of the free ligands and the Pt(II) compounds revealed that the molecular shape and geometry of the molecule have a distinct impact on the fluorescence and phosphorescence of these molecules. Pt-1 is a bright, phosphorescent emitter with lambda(em) 490 nm and Phi = 66% while Pt-2 is very weakly emissive with lambda(em) 567 nm and Phi = similar to 0.05%. Anions such as fluoride were found to have no impact on the phosphorescence of these two Pt(II) compounds, thus establishing that phosphorescence of these molecules does not involve a through-space charge transfer transition between the Pt(ppy) (acac) unit and the BMes(2)Ar unit.
- 出版日期2011-9-12
