Strong Dipolar Effects on an Octupolar Luminiscent Chromophore: Implications on their Linear and Nonlinear Optical Properties

Abstract

Design parameters derived from structure-property relationships play a very important role in the development of efficient molecular-based functional materials with optical properties. Here, we report on the linear and nonlinear optical properties of a fluorene-derived dipolar system (DS) and its octupolar analogue (OS), in which donor and acceptor groups are connected by a phenylacetylene linkage, as a strategy to increase the number of delocalized electrons in the π-conjugated system. The optical nonlinear response was analyzed in detail by experimental and theoretical methods, showing that, in the octupolar system OS, the dipolar effects induced a strong two-photon absorption process whose magnitude is as large as 2210 GM at infrared wavelengths. Solvatochromism studies were implemented to obtain further insight on the charge transfer process. We found that the triple bond plays a fundamental role in the linear and nonlinear optical responses. The strong solvatochromism behavior in DS and OS was analyzed by using four empirical solvent scales, namely Lippert-Mataga, Kamlet-Taft, Catalán, and the recently proposed scale of Laurence et al., finding consistent results of strong solvent polarizability and viscosity dependence. Finally, the role of the acceptor groups was further studied by synthesizing the analogous compound 2DS, having no acceptor group.

Electronic Absorption, Emission, and Two-Photon Absorption Properties of Some Extended 2,4,6-Triphenyl-1,3,5-Triazines

“…In line with similar studies made for 1-X, 2-X and related derivatives [11,12,18,27], solvatochromic studies on 3-NPh 2 revealed a relatively solvent-insensitive absorption but a very solvent-sensitive emission for such a symmetrical D 3h molecule [47]. The shift to lower energy observed on proceeding to the most polar solvent suggests that the excited state was more polarised than the ground state.…”

“…The desired 3-X, 4, and 7-X derivatives are structurally close to known s-triazine derivatives [15][16][17]27,[34][35][36][37][38][39][40]. The 3-X series corresponds to the simplest derivatives in which the 1,3,5-triphenyl-s-triazine core has been extended with a phenyl-alkynyl linker and terminated with X-groups of varying electron-donor/acceptor power.…”

“…Thus far, emissive triphenyl-s-triazine derivatives and related extended analogues have mainly raised interest in the field of OLEDs or closely related fields [15][16][17][18]; however, very few studies were actually focused on the NLO properties of such derivatives. While related derivatives such as extended trialkynyl-s-triazines [19], trialkenyl-s-triazines [20,21], or tris(2-thienyl)-s-triazines [22][23][24][25] have given rise to some 2PA investigations, to the best of our knowledge, only one recent theoretical paper deals specifically with the second-order NLO properties of molecules such as 3-X [26], and only one other single paper addresses the 2PA properties of an s-triazine derivative closely related to 7-H [27]. Thus, regarding extended triphenyl-s-triazines, essentially styryl-type analogues of 3-X have been investigated so far for their 2PA properties [28][29][30].…”

An Application Exploiting Aurophilic Bonding and iClick to Produce White Light Emitting Materials

“…The following materials were purchased and used as received: chlorotriethylphosphine gold­(I) (PEt 3 AuCl; Sigma-Aldrich), chlorotriphenylphosphine gold­(I) (PPh 3 AuCl; Strem), and azidotrimethylsilane (TMSN 3 ; Acros). The following were prepared by literature methods: PEt 3 AuN 3 , PPh 3 AuN 3 , and 2-ethynyl-9,9-dioctyl-9 H -fluorene . Prepatterned indium tin oxide (ITO) coated glass substrates were purchased from Kintec.…”

Designed Synthesis and Crystallization of Isomorphic Molecular Gyroscopes with Cell-like Bilayer Self-Assemblies

“…Solvents were purified by distillation over appropriate drying agents. Compounds 2 – 4 were obtained following reported methodologies; − spectroscopic data are in good agreement.…”