Publication
Title
Functionalized picolinium quinodimethane chromophores for electro-optics: synthesis, aggregation behavior, and nonlinear optical properties
Author
Abstract
A new series of functionalized and thermally stable zwitterionic picolinium (dicyano)esterquinodimethane (PeQDM) chromophores have been synthesized in one step from 7,8-di(methoxycarbonyl)-7,8-dicyanoquinodimethane (DMCQ) and various picolinium salts in methanol in nearly 50% overall yields. Hyper-Rayleigh scattering (HRS) measurements at 1.07 Êm show very large near-resonant molecular first hyperpolarizabilities À up to 1800 ~ 10−30 esu, despite the fact that, compared to previously studied zwitterionic NLO chromophores, one of the strong CN acceptor groups is substituted by a weaker ester group to allow for further functionalization. The ester functionality can be further utilized for attachment of solubility-imparting groups, cross-linkers, and reactive groups for grafting the chromophore onto a polymer. To optimize the electro-optic (EO) activity in the polymer matrix, the aggregation behavior of the PeQDM chromophores is studied. X-ray crystallographic analysis confirms the charge-separated ground-state of PeQDM and reveals the formation of a face-to-face, antiparallel H-aggregation with a large slip angle (Æ = 64.5) between the chromophores. In a less polar polymer matrix, PeQDM chromophores can form H- and/or J-aggregates and only J-aggregates could contribute to the EO activity if the monomeric chromophores released during the thermally induced J−H transformation could be captured and effectively poled. In a more polar polymer host, chromophores are well dissolved as monomers and effectively poled. A large and stable EO activity (r33 = 110 pm/V) has been achieved with a polyethersulfone film doped with 5 wt % of N-benzyl picolinium (dicyano)esterquinodimethane (PeQDM-Ben).
Language
English
Source (journal)
Chemistry of materials / American Chemical Society. - Washington, D.C.
Publication
Washington, D.C. : 2008
ISSN
0897-4756
Volume/pages
20:24(2008), p. 7465-7473
ISI
000261800700016
Full text (Publisher's DOI)
UAntwerpen
Faculty/Department
Research group
[E?say:metaLocaldata.cgzprojectinf]
Selective linear and nonlinear optical spectroscopy of carbon nanotubes and their interactions with organic molecules.
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 03.04.2009
Last edited 01.08.2017
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