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

Abstract

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, the inner 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 and two-photon absorption induced emission spectra of the molecules in THF solutions. The results were compared with 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 (Coumarin 110) were determined and used as a reference material. The two-photon absorption cross section around 720-740 nm of ATP1 and ATP2 was found to be of the same order of magnitude as for Pt1-G1, i.e., between 5 and 10 GM, but slightly larger for ATP1 than for ATP2 (1 GM = 1 Göppert-Mayer = 10(-50) (cm(4) s)/photon). The fluorescence decay time of all compounds was found to be very short (subnanosecond) with quantum yields 0.0045, 0.0007, 0.0011 and 0.0020 for ATP1, ATP2, Pt1-G1 and Pt1, respectively, measured at excitation wavelength 373 nm. Just as Pt1 and Pt1-G1, both thiophenyl derivatives showed large intersystem crossing capabilities and phosphorescence, characteristic for a triplet state that can enhance the nonlinear absorption and optical power limiting by triplet state absorption. The phosphorescence emission of the thiophenyl derivatives was red-shifted in comparison with Pt1 and Pt1-G1, and the phosphorescence decay times were on the order of 200-500 ns, as for the Pt1 compound.

Preparation of Functional Hybrid Glass Material from Platinum (II) Complexes for Broadband Nonlinear Absorption of Light

“…Emission spectra of the hybrid glass 1b were acquired using a ms flashlamp as excitation. This experiment revealed emissions in accord with that of 1a in solution, [5,13,[15][16][17]27] in the region of 400-450 nm and 500-600 nm, as expected for fluorescence and phosphorescence, respectively (Fig. 8).…”

“…[5,10,11] Complex 1a has been extensively studied in solution for its nonlinear absorption properties, [5,[10][11][12] and we have recently prepared several related molecules with repeating arylethynyl groups in trans configuration for comparisons with 1a. [13][14][15][16][17] The solution OPL studies of platinum polymeric structures have also been reported recently. [18][19][20] The solutions of the compounds (usually in tetrahydrofuran) show good OPL properties and are fairly transparent in the visible region.…”

Optical Properties of Hybrid Organic‐Inorganic Materials and their Applications

“…For instance the platinum(II) square-planar complex trans-[P(n-Bu) 3 ] 2 Pt[(C C-p-C 6 H 4 -C C-p-C 6 H 5 ] 2 [326,346,347] was reported for efficient nonlinear absorption in solution, [326,[346][347][348] and series of derivatives were prepared with improved properties. [294,[349][350][351][352][353][354][355][356][357][358] The use of PMMA monoliths hosting platinum derivatives was an efficient route towards OPL materials. [278,359] The measured linear transmissions were nearly 90% in the visible and NLO properties were maintained in the solid.…”

Efficient Nonlinear Absorbing Platinum(II) Acetylide Chromophores in Solid PMMA Matrices

“…porphyrins and fullerens, and consequently these dyes have obvious limitations for use as sensor protection within the visible wavelength region. [14] Platinum(II) acetylides on the other hand, are only slightly colored and well known to possess strong excited state absorption, [21][22][23][24][25] giving rise to efficient nonlinear absorbing properties. [15] Previous results presented by a number of authors, [21,[25][26][27][28][29][30][31] demonstrate the fundamental photophysical properties of platinum (II) acetylides and discuss their potential use in optical power limiting (OPL) applications.…”