Push-Pull Tricyanovinyl-Substituted Thienylpyrroles: Synthesis, Solvatochromic and Electrochemical Properties

Abstract

New tricyanovinyl-derivatives 1 of 1-(alkyl)aryl-2-(2'-thienyl)pyrroles 2 have been synthesized and characterized. Compounds 1 display dramatic reductions in both their optical and electrochemical band gaps in comparison to thienylpyrroles 2. The solvatochomic behavior of tricyanovinyl-derivatives 1 was investigated in a variety of solvents. In agreement with the solvatochromic and the electrochemical studies for pushpull derivatives I the new compounds prepared, can find application for manufacturing new materials with notable non-linear optical properties.

Highly efficient and thermally stable NLO organic materials based on pyrrole and thiophene heterocycles

“…Previous studies have demonstrated that donor-acceptor substituted pyrroles exhibit a positive solvatochromism. [8][9][10][11][12][19][20] In this case a moderate to large positive solvatochromism (Δν max = 488-981 cm -1 ) was observed moving from diethyl ether to DMSO solutions for derivatives 1a-e. The UV-visible spectra of 1b in ethyl ether and in DMSO are given in figure 5.…”

“…spectra is observed when stronger acceptor groups are linked to the heterocyclic system. [8][9][10][11][12][19][20] As a result the substitution of a formyl group for a 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile moiety leads to a red shift of 170 nm from 348 nm (1a) to 510 nm (1e). Within the series 1a-e the CT bands moves to lower energy as the electron accepting ability of the acceptor moiety increases, in the order CHO < dicyanovinyl < rhodanine < thiobarbituric acid < 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (Fig.…”

“…Recently we were able to overcome these difficulties and reported on the interesting electrochemical and solvatochromic properties and the first hyperpolarizabilities of pyrrolecontaining NLO chromophores with potential application as nonlinear optical compounds. [8][9][10][11][12] We were therefore motivated to extend these studies and explore the potential of a novel series 1-(4-(thiophen-2-yl)phenyl)-1H-pyrroles 1 as efficient push-pull systems bearing pyrrole as donor group and dicyanovinyl, rhodanine, thiobarbituric acid and indanonedicyanovinyl as acceptor moieties linked through an arylthiophene spacer.…”