Efficient acceptor groups for NLO chromophores : Competing inductive and resonance contributions in heterocyclic acceptors derived from 2-dicyanomethylidene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Karin Schmidt
  • Stephen Barlow
  • Amalia Leclercq
  • Egbert Zojer
  • Sei-Hum Jang
  • Seth R. Marder
  • Jean-Luc Brédas

Detail(s)

Original languageEnglish
Pages (from-to)2944-2949
Journal / PublicationJournal of Materials Chemistry
Volume17
Issue number28
Publication statusPublished - 2007
Externally publishedYes

Abstract

The 2-dicyanomethylidene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF) group has been identified as a particularly strong acceptor suitable for the realization of highly efficient second-order NLO chromophores. To provide guidelines for a further improvement of heterocyclic acceptors, we present Sum-Over-States (SOS) calculations of second-order polarizabilities (β) for a series of donor-π-bridge-acceptor (D-π-A) chromophores. In particular, we investigate the effect of replacing the oxygen atom of the furan ring in TCF by a variety of other groups, X (SiH2, CH2, CCH 2, NH, CO, S, CCHNO2, SO, and SO2). Overall β is found to increase with the inductive electron-withdrawing character of X, with β being further increased or decreased when X has π-accepting or π-donating character. Within the framework of the two-level model, the effects associated with the π-donating and accepting character can be understood in terms of destabilizing and stabilizing effects on the lowest unoccupied molecular orbitals of the dipolar chromophores. When using the stronger 3-methyl-4-cyano-5-dicyanomethylidene-2-oxo-3-pyrroline (TCP) acceptor and replacing the pyrroline nitrogen atom with the same range of X groups, the inductive electron-withdrawing and π-accepting or π-donating characters of X have the same impact on β as in the TCF motif. © The Royal Society of Chemistry.

Citation Format(s)

Efficient acceptor groups for NLO chromophores : Competing inductive and resonance contributions in heterocyclic acceptors derived from 2-dicyanomethylidene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran. / Schmidt, Karin; Barlow, Stephen; Leclercq, Amalia; Zojer, Egbert; Jang, Sei-Hum; Marder, Seth R.; Jen, Alex K.-Y.; Brédas, Jean-Luc.

In: Journal of Materials Chemistry, Vol. 17, No. 28, 2007, p. 2944-2949.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review