One‐Photon Photophysics and Two‐Photon Absorption of 4‐[9,9‐Di(2‐ethylhexyl)‐7‐diphenylaminofluoren‐2‐yl]‐2,2′:6′,2′′‐terpyridine and Their Platinum Chloride Complexes

Abstract

The synthesis, one-photon photophysics and two-photon absorption (2PA) of three dipolar D-π-A 4-[9,9-di(2-ethylhexyl)-7-diphenylaminofluoren-2-yl]-2,2':6',2''-terpyridine and their platinum chloride complexes with different linkers between the donor and acceptor are reported. All ligands exhibit (1)π,π* transition in the UV and (1)π,π*/(1)ICT (intramolecular charge transfer) transition in the visible regions, while the complexes display a lower-energy (1)π,π*/(1)CT (charge transfer) transition in the visible region in addition to the high-energy (1)π,π* transitions. All ligands and the complexes are emissive at room temperature and 77 K, with the emitting excited state assigned as the mixed (1)π,π* and (1)CT states at RT. Transient absorption from the ligands and the complexes were observed. 2PA was investigated for all ligands and complexes. The two-photon absorption cross-sections (σ(2)) of the complexes (600-2000 GM) measured by Z-scan experiment are much larger than those of their corresponding ligands measured by the two-photon induced fluorescence method. The ligand and the complex with the ethynylene linker show much stronger 2PA than those with the vinylene linker.

Synthesis, Structural Characterization, Photophysics, and Broadband Nonlinear Absorption of a Platinum(II) Complex with the 6‐(7‐Benzothiazol‐2′‐yl‐9,9‐diethyl‐9 H‐fluoren‐2‐yl)‐2,2′‐bipyridinyl Ligand

“…To separate the contribution of singlet excited‐state absorption from triplet excited‐state absorption, and the contribution of TPA from excited‐state absorption (in the near‐IR region), open‐aperture Z scans were performed in a CH 2 Cl 2 solution at 532 nm by using both ns and ps laser pulses and at a variety of visible and near‐IR wavelengths by using ps pulses. The experimental data were then fitted by using the five‐level model described previously5g,n,q,s, 20 with the input parameters ( σ 0 , τ s , τ T , Φ T ) obtained from the photophysical studies described above to abstract both the singlet and triplet excited‐state absorption cross sections ( σ s and σ T ) and the TPA cross sections ( σ 2 ). Representative Z ‐scan data and fitting curves are provided in Figure 9.…”

Small water-soluble pyrimidine hexafluorophosphate derivatives with high two-photon absorption activities in the near-IR region and their biological applications

“…Thus, the two photon cross section values obtained by the Z-scan method could be overestimated compared to that obtained by the two-photon excited uorescence method due to the fact that no inuence of uorescence quantum yield was considered in the measurement. 29 However, the results of s values obtained by the Z-scan method have a magnitude equal to that of the values obtained by the twophoton excited uorescence method. The reason for this may be attributed to the fact that an fs laser was used as the light source.…”

Two new POM-based compounds modified by lanthanide–Schiff base complexes with interesting NLO properties

“…It is an acknowledged phenomenon that the existence of -electron delocalization in the skeleton structure leads to a better response with respect to third-order nonlinear optics (NLO) (Ji et al, 2011, Asif et al, 2017. Thus, the third-order NLO properties of 1 and 2 were investigated by open-aperture Z-scan experiments in dimethylformamide (DMF) at a concentration of 1.0 Â 10 À4 mol l À1 (Figs.…”