Optical limiting in the visible range: molecular engineering around N⁴,N^4′-bis(4-methoxyphenyl)-N⁴,N^4′-diphenyl-4,4′-diaminobiphenyl

Abstract

We describe the synthesis and nonlinear absorption properties of triarylamine derivatives. Six molecules were synthesised by using a double Ullmann coupling procedure. UV-Vis absorption spectra show the excellent transparency of these triarylamine derivatives in the visible range (l cut-off ¡ 420 nm). Nonlinear absorption measurements show a broadband nonlinear absorption range extending between 450-650 nm with an optimised efficiency for a planar conjugated system (fluorene, molecule 10) or a hindered donor group (molecule 12). These data were interpreted by means of a two step three-photon absorption scheme: a TPA process followed by an S 1 AS n ESA step; the product of both spectra is qualitatively in good agreement with nonlinear absorption spectra, leading to different molecular engineering approaches for optimisation of these features in the visible range through TPA and/or ESA properties.

Two‐Photon Absorption‐Related Properties of Functionalized BODIPY Dyes in the Infrared Range up to Telecommunication Wavelengths

“…3), and a higher-order effect related to a three-photon absorption, such as a TPA-induced excited-state absorption (ESA) was taken into account. Consequently, as already observed in the NIR for cyanine dyes [20] or in the visible, [39,40] the propagation in Equation 1 becomes…”

Conformational Tuning of the Intramolecular Electronic Coupling in Molecular‐Wire Biruthenium Complexes Bridged by Biphenyl Derivatives

“…Others were commercially available. The starting materials [RuHCl (CO)(PPh 3 ) 3 ], [73] 2,7-diiodofluorene (1a), [74] 2,7-diiodo-9,10-dihydrophenanthrene (1b), [60] 4,4'-diiodo-2,2'-dimethylbiphenyl (1d), [60] 4,4'-diiodo-2,2',6,6'-tetramethylbiphenyl (1e), [75] and [RuCl(CO)(PMe 3 ) 3 (CH=CHC 6 H 5 )] (5) [76] were prepared by the procedures described in the literature. Synthesis of diethynyl biphenyl derivatives 2,7-Bis(ethynyl)fluorene (3 a):2 ,7-Bis(trimethylsilylethynyl)fluorene (2a,0 .36 g, 1mmol) was dissolved in am ixture of THF (6 mL) and methanol (6 mL).…”

Molecular Engineering of Photoremovable Protecting Groups for Two‐Photon Uncaging

“…These efforts have led to various possible approaches for increasing the TPA properties of chromophores or fluorophores. Different chromophore geometries have been investigated, with linear (1D), [18,19] planar (2D), [20,21] and tetrahedral (3D) [22] structures. The typical dipolar architecture of a 1D TPA chromophore, the smallest system to be useful in biology, is generally composed of two electron-donor or electron-acceptor groups (D or A) linked to a central core by conjugated systems.…”