Novel highly conjugated push-pull 4,5-diazafluoren-9-ylidene based efficient HLO chromophores as a springboard for coordination complexes with large second-order NLO properties

摘要

Two new ligands L~n: N,N-dibutyl-(4,5-diazafluorenyl-9-ylidene-penta-l,3-dienyl)-amine (L~2) and 9-[(l-azulenyl)methylene]-4,5-diazafluorene (L~3), along with the related Zn(n) complexes with ancillary ligands of different electron withdrawing strengths ([Zn(CH3CO2)2L~n], [Zn(CF3CO2)2L~n] and [Zn(CF3SO3)2L~n]) were prepared and characterized. Their remarkable second-order NLO properties were investigated using the EFISH technique. The μβ_(1.91) value of [Zn(CF3SO3)2L~2] is strongly dependent on concentration, reaching, to our knowledge, the highest value reported for a Zn(II) complex.