Excited States and Two-Photon Absorption of Some Novel Thiophenyl Pt(II)-Ethynyl Derivatives

详细信息    查看全文

• 作者：Eirik Glimsdal ; Marcus Carlsson ; Bertil Eliasson ; Boris Minaev ; Mikael Lindgren
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：January 18, 2007
• 年：2007
• 卷：111
• 期：2
• 页码：244 - 250
• 全文大小：273K
• 年卷期：v.111,no.2(January 18, 2007)
• ISSN：1520-5215

文摘

The photophysical characterization of two new compounds related to bis((4-(phenylethynyl)phenyl)ethynyl)bis(tributylphosphine)platinum(II), here abbreviated Pt1, is reported. For the first new compound ATP1, theinner phenyl rings (closer to the Pt atom) in Pt1 are replaced by thiophene rings bridging at the 2,5-positions.In compound ATP2, the outer phenyl groups are replaced by thiophene rings bonded at the 2-position.Specifically, we report on the fluorescence quantum yield, two-photon absorption, triplet decay times andtwo-photon absorption induced emission spectra of the molecules in THF solutions. The results were comparedwith those of Pt1 and Pt1 capped with an acetonide-protected 2,2-bis(methylol)propionic acid (bis-MPA)ester group (Pt1-G1). The photophysical properties of the organic dye 7-(diethylamino)coumarin (Coumarin110) were determined and used as a reference material. The two-photon absorption cross section around720-740 nm of ATP1 and ATP2 was found to be of the same order of magnitude as for Pt1-G1, i.e., between5 and 10 GM, but slightly larger for ATP1 than for ATP2 (1 GM = 1 Göppert-Mayer = 10^-50 (cm⁴ s)/photon). The fluorescence decay time of all compounds was found to be very short (subnanosecond) withquantum yields 0.0045, 0.0007, 0.0011 and 0.0020 for ATP1, ATP2, Pt1-G1 and Pt1, respectively, measuredat excitation wavelength 373 nm. Just as Pt1 and Pt1-G1, both thiophenyl derivatives showed large intersystemcrossing capabilities and phosphorescence, characteristic for a triplet state that can enhance the nonlinearabsorption and optical power limiting by triplet state absorption. The phosphorescence emission of thethiophenyl derivatives was red-shifted in comparison with Pt1 and Pt1-G1, and the phosphorescence decaytimes were on the order of 200-500 ns, as for the Pt1 compound.