Quadrupolar D-π-A-π-D chromophores with central tetrafluorobenzene acceptor and two peripheral N,N-dimethylamino and methoxy donors

Abstract

1,2,4,5-Tetrafluorobenzene has been utilized as suitable central acceptor moiety in push–pull chromophores having D-π-A-π-D quadrupolar arrangement. Starting from commercially available 1,4-diiodotetrafluorobenzene, nine novel chromophores with systematically extended π-system were synthesized via cross-coupling reactions. Further electronic tuning has been achieved by variation of the appended donor (N,N-dimethylamino and methoxy groups). Target chromophores were further investigated by X-ray analysis, electrochemical measurements, absorption and emission spectra and theoretical calculations and structure–property relationships were elucidated. Whereas target chromophores showed weak second-order nonlinear responses with β of 0.18–6.09×10−30esu, which is primarily given by their centrosymmetric arrangement, third-order polarizabilities γ of 0.84–22.5×10−27esu notably exceeded the standard Disperse Red 1 (γ=3.47×10−27esu).