Stimuli-responsive NLO properties of tetrathiafulvalene-fused donor–acceptor chromophores. Issue 33 (15th August 2017)

• Record Type: Journal Article
• Authors: Cariati, E.; Liu, X.; Geng, Y.; Forni, A.; Lucenti, E.; Righetto, S.; Decurtins, S.; Liu, S.-X.
• Is Part Of: Physical chemistry chemical physics. Volume 19:Issue 33(2017)
• Page Start: 22573
• Page End: 22579
• Publication Date: 2017-08-15
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp04687a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Tetrathiafulvalene-fused electron donor–acceptor dyads display second order nonlinear optical properties that can be triggered by a pH or a redox stimulus. Abstract : The second-order nonlinear optical (NLO) properties of two tetrathiafulvalene (TTF)-fused electron donor–acceptor dyads have been determined using the Electric Field Induced Second Harmonic generation (EFISH) technique and theoretically rationalized. Dyads TTF-dppz (1 ) and TTF-BTD (2 ) were obtained by direct fusion of a TTF electron donor unit either with a dipyrido[3, 2- a :2′, 3′- c ]phenazine (dppz) or a benzothiadiazole (BTD) electron acceptor moiety. Dyad1 acts as a reversible acido-triggered NLO switch by protonation/deprotonation at two nitrogen atoms of the dppz acceptor moiety induced by sequential exposure to HCl and ammonia vapors. Dyad2, on the other hand, displays redox-tunable NLO properties upon two consecutive oxidations to its radical cation2 + ˙ and dication2 2+ species. The resulting final dication2 2+ exhibits an inversion of the sign of β 0, due to a completely inverted distribution of the frontier molecular orbitals with respect to those of its neutral species, leading to a scarcely polar species in the excited state, as indicated by the theoretical calculations.