title: Synthesis, spectral and redox switchable cubic NLO properties of chiral dinuclear iron cyanide/isocyanide-bridged complexes.
abstract: Two chiral dinuclear cyanide/isocyanide-bridged complexes (R)-[Cp(dppe)Fe-CN-Fe(dppp)Cp]PF6 (1[PF6]) and (R)-[Cp(dppe)Fe-NC-Fe(dppp)Cp]PF6 (2[PF6]), and their mono-oxidation products (R)-[Cp(dppe)Fe(II)-CN-Fe(III)(dppp)Cp] [PF6]2 (1[PF6]2) and (R)-[Cp(dppe)Fe(III)-NC-Fe(II)(dppp)Cp][PF6]2 (2[PF6]2) were synthesized and fully characterized. The electronic spectra of both the mixed-valence complexes 1[PF6]2 and 2[PF6]2 exhibit a strong and broad absorption band with two discernable peaks in the NIR region, which are attributed to Fe(II)-Fe(III) IVCT transitions. The attributions are supported by the DFT calculations. Under irradiation with a nanosecond laser at 1064 nm, the measured third-order NLO results of all four cyanide-bridged complexes showed that complexes 1(+) and 2(+) do not exhibit an NLO response, but their one-electron oxidation complexes 1(2+) and 2(2+) exhibit a strong NLO response due to a resonance enhanced effect. In addition, both complexes 1(2+) and 2(2+) display RSA and self-defocusing effects and show good optical limiting behavior in a broadband range.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Ma
authors.forename: Chen-Sheng
authors.initials: CS
authors.lastname: Lin
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Yi-Ji
authors.initials: YJ
authors.lastname: Lin
authors.forename: Sheng-Min
authors.initials: SM
authors.lastname: Hu
authors.forename: Tian-Lu
authors.initials: TL
authors.lastname: Sheng
authors.forename: Xin-Tao
authors.initials: XT
authors.lastname: Wu