Página principal > Artículos > Twisted One-Dimensional Charge Transfer and Related Y-Shaped Chromophores with a 4 H-Pyranylidene Donor: Synthesis and Optical Properties
Resumen: Three series of push-pull derivatives bearing 4H-pyranylidene as electron donor group and a variety of acceptors were designed. On one hand, one-dimensional chromophores with a thiophene ring (series 1H) or 5-dimethylaminothiophene moiety (series 1N) as an auxiliary donor, non-coplanar with the p-conjugated system, were synthesized. On the other hand, related two-dimensional (2D) Y-shaped chromophores (series 2) were also prepared to compare how the diverse architectures affect the electrochemical, linear, and second-order nonlinear optical (NLO) properties. The presence of the 5-dimethylaminothiophene moiety in the exocyclic C= C bond of the pyranylidene unit gives rise to oxidation potentials rarely low, and the protonation (with an excess of trifluoroacetic acid) of its derivatives results in the apparition of a new blue-shifted band in the UV-visible spectra. The analysis of the properties of derivatives with and without the additional thiophene ring shows that this auxiliary donor leads to a higher NLO response, accompanied by an enhanced transparency. Y-shaped chromophores of series 2 present a blue-shifted absorption, higher molar extinction coefficients, and higher Eox values compared to their linear twisted counterparts. As concerns NLO properties, 2D Y-shaped architecture gives rise to somewhat lower µß values (except for thiobarbiturate derivatives). Idioma: Inglés DOI: 10.1021/acs.joc.0c02438 Año: 2021 Publicado en: Journal of Organic Chemistry 86 (2021), 3152-3163 ISSN: 0022-3263 Factor impacto JCR: 4.198 (2021) Categ. JCR: CHEMISTRY, ORGANIC rank: 12 / 57 = 0.211 (2021) - Q1 - T1 Factor impacto SCIMAGO: 0.983 - Organic Chemistry (Q1)