Imidazole as a central π-linkage in Y-shaped push–pull chromophores

Twelve imidazole based Y-shaped push–pull chromophores have been designed, synthesised and fully characterised featuring 4,5-bis(N,N-dimethylanilino)imidazole as a donor moiety, a systematically enlarged π-linker and nitro and cyano groups as acceptors. The synthesised push–pull systems have been studied by electrochemistry, UV/Vis and IR spectroscopy and nonlinear optical properties have been calculated. Moreover, quantitative relationships between the measured and calculated properties and the structural features have also been evaluated. Electrochemical and spectral properties have mainly been affected by the presence of strongly conjugating acceptors, large π-linkers and the spatial arrangement of the chromophore.

Research highlights
► Imidazole as a central p-conjugated unit in charge-transfer chromophores.
► N,N-Dimethyl amino and cyano/nitro groups as donor and acceptors.
► Chromophores were studied by electrochemistry, UV/Vis, IR and NLO calculations.
► Strong acceptor, large p-linker and planarity mostly affect NLO properties.