Syntheses and structures’ influence on the nonlinear optical properties of o-ferrocenylbenzoate compounds

Two complexes containing o-ferrocenylbenzoate [o-−OOCH4C6Fc, Fc = (η5-C5H5)Fe(η5-C5H4)] components: {[Pb(η2-o-OOCH4C6Fc)2(phen)](NO3)} (phen = phenanthroline) (1) and {[Zn(η2-o-OOCH4C6Fc)2(bpe)](CH3OH)}n (bpe = 1,2-bis(4-pyridyl) ethene) (2) have been synthesized and structurally characterized by single crystal X-ray diffraction. 1 gives a discrete mononuclear framework, 2 features an infinite 1-D chain structure constructed by the bpe linking two adjacent zinc (II) ions. The third-order nonlinear optical (NLO) properties of complexes 1, 2 and the reactant o-NaOOCH4C6Fc were determined by Z-scan techniques in DMF solution. The results show that the structures of complexes have great impact on NLO properties. Complex 1 and o-NaOOCH4C6Fc display self-defocusing behaviors, while complex 2 exhibits strong self-focusing effect. The solution-state differential pulse voltammograms of complexes 1, 2 and o-NaOOCH4C6Fc were investigated as well. The results reveal that the half-wave potential of the ferrocenyl moieties is strongly influenced by the Pb(II) or Zn(II) ions in complexes 1 and 2.