Cationic π-electron systems with high quadratic hyperpolarisability
| Autor: | Christoph Lambert, Elmar Schmälzlin, Christoph Bräuchle, Gilbert Nöll, Wolfgang Gaschler, Klaus Meerholz, Matthias Weber |
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| Rok vydání: | 2001 |
| Předmět: | |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1364-5471 1472-779X |
| DOI: | 10.1039/b009664b |
| Popis: | Cationic NLO-chromophores based on tolane π-systems in which conventional electron donors are combined with ionic pyridinio or triorganoammonio and -phosphonio substituents, respectively, perform much better than conventional donor/acceptor-substituted (D/A-substituted) tolanes concerning their hyperpolarisability–transparency trade-off. This effect occurs because ionic acceptors do not enlarge the π-system in contrast to conventional acceptors. The same holds true for benzene-type chromophores. Despite their different electronic nature, the extrapolated maximal high-energy absorption of the ionic chromophore series as well as of the conventional donor/acceptor-tolanes coincide at the absorption energy of unsubstituted tolane. This proves that the maximal blue transparency of a given series of substituted chromophores is governed by the absorption maximum of the unsubstituted parent chromophore. In this way chromophores have been designed with much higher quadratic hyperpolarisability than e.g.p-nitroaniline at about the same absorption wavelength. By applying the same concept, a two- and a three-dimensional highly efficient octupolar NLO-chromophore assembly has also been synthesised. |
| Databáze: | OpenAIRE |
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