Synthesis, spectral and redox switchable cubic NLO properties of chiral dinuclear iron cyanide/isocyanide-bridged complexes

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 42; no. 34; pp. 12452 - 12459
• Main Authors: Ma, Xiao, Lin, Chen-Sheng, Zhang, Hui, Lin, Yi-Ji, Hu, Sheng-Min, Sheng, Tian-Lu, Wu, Xin-Tao
• Format: Journal Article
• Language: English
• Published: England 14.09.2013
• Subjects: Constraining; Electronic spectra; Lasers; Mathematical analysis; Nanocomposites; Nanomaterials; Nanostructure; Spectra
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c3dt51197a

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.