Density functional theory（DFT） calculations were carried out to investigate the geometry structures, redox properties and second-order nonlinear optical（NLO） properties of ferrocene（Fc）-dithiolenes hybrid comple...Density functional theory（DFT） calculations were carried out to investigate the geometry structures, redox properties and second-order nonlinear optical（NLO） properties of ferrocene（Fc）-dithiolenes hybrid complexes. The switchable second-order NLO properties of these complexes are induced by the redox process. The oxidized process significantly affects the geometrical structures of the dithiolene moieties, that is, the embowed dithiolene moieties change into planar structures. It supports that the dithiolene moieties are the oxidized center. The βtot values of the cationic species are at least 4 and 10 times those of their corresponding parent complexes, respectively. Further, the time-dependent DFT calculation illustrates that the low-energy absorption（which is helpful for the large NLO response） is mainly assigned to intra-ligand charge transfer [π（ex-dithiolene）→π（ex-dithiolene）]. These results suggest the potential use of the novel Fc-based dithiolenes complexes as versatile and fascinating NLO switching materials.展开更多
The reaction of CuCl2-2H2O or NiCl2.6H2O with K2(C5H6S4) [potassium salt of 6,7-dihydro-5H-1,4-dithiepin-2,3-dithiolate] under nitrogen atmosphere resulted in the isolation of [Cu(C5H6S4)2]- or [Ni(C5H6S4)2]- as the t...The reaction of CuCl2-2H2O or NiCl2.6H2O with K2(C5H6S4) [potassium salt of 6,7-dihydro-5H-1,4-dithiepin-2,3-dithiolate] under nitrogen atmosphere resulted in the isolation of [Cu(C5H6S4)2]- or [Ni(C5H6S4)2]- as the tetrabutylammonium salt. Both complexes show characteristic IR and UV-Vis absorptions of transition metal dithiolenes. Cyclic voltammograms contain two waves indicating a two step electrochemical procedure [M(C5H6S4)2]0 = [M(C5H6S4)2]1-= [M(C5H6S4)2]2-. Single crystal structure study has been carried out on the nickel complex. Crystal of [Bu4N][Ni(C5H6S4)2] belongs to monoclinic space group P21/c with a=17.576(5), 6=10.883(2), c=17.773(4) A,B=91.07(2)0, Z=4, and o(calcd.)=1.348 g/cm3. Final result is R=0.059 for 2959 reflections. The NiS4 core exhibits square planar coordination with average Ni-S bond length of 2.134(5) A. There are not anion pairs in crystal. The anions stack along a and c axes while the cations intercalate in them. The nearest S-S contact is 4.429 A. The solid powder ESR spectrum of the nickel complex shows three broadening signals at g1=2.097, g2=2.042, g3=2.022. Magnetic susceptibility data for [Bu4N][Ni(CgH6S4)2] reveal enhanced anti-ferromagnetic interaction.展开更多
基金Supported by the National Natural Science Foundation of China（No.41471165）, the Natural Science Foundation of Jilin Province, China（No.20130101081JC） and the Scientific Research Found of Jilin Agricultural University China（No.2015049）.
文摘Density functional theory（DFT） calculations were carried out to investigate the geometry structures, redox properties and second-order nonlinear optical（NLO） properties of ferrocene（Fc）-dithiolenes hybrid complexes. The switchable second-order NLO properties of these complexes are induced by the redox process. The oxidized process significantly affects the geometrical structures of the dithiolene moieties, that is, the embowed dithiolene moieties change into planar structures. It supports that the dithiolene moieties are the oxidized center. The βtot values of the cationic species are at least 4 and 10 times those of their corresponding parent complexes, respectively. Further, the time-dependent DFT calculation illustrates that the low-energy absorption（which is helpful for the large NLO response） is mainly assigned to intra-ligand charge transfer [π（ex-dithiolene）→π（ex-dithiolene）]. These results suggest the potential use of the novel Fc-based dithiolenes complexes as versatile and fascinating NLO switching materials.
基金Project supported by grants for key research project in climbing program from the State Science and Technology Commission,and the National Nature Science Foundation of China.
文摘The reaction of CuCl2-2H2O or NiCl2.6H2O with K2(C5H6S4) [potassium salt of 6,7-dihydro-5H-1,4-dithiepin-2,3-dithiolate] under nitrogen atmosphere resulted in the isolation of [Cu(C5H6S4)2]- or [Ni(C5H6S4)2]- as the tetrabutylammonium salt. Both complexes show characteristic IR and UV-Vis absorptions of transition metal dithiolenes. Cyclic voltammograms contain two waves indicating a two step electrochemical procedure [M(C5H6S4)2]0 = [M(C5H6S4)2]1-= [M(C5H6S4)2]2-. Single crystal structure study has been carried out on the nickel complex. Crystal of [Bu4N][Ni(C5H6S4)2] belongs to monoclinic space group P21/c with a=17.576(5), 6=10.883(2), c=17.773(4) A,B=91.07(2)0, Z=4, and o(calcd.)=1.348 g/cm3. Final result is R=0.059 for 2959 reflections. The NiS4 core exhibits square planar coordination with average Ni-S bond length of 2.134(5) A. There are not anion pairs in crystal. The anions stack along a and c axes while the cations intercalate in them. The nearest S-S contact is 4.429 A. The solid powder ESR spectrum of the nickel complex shows three broadening signals at g1=2.097, g2=2.042, g3=2.022. Magnetic susceptibility data for [Bu4N][Ni(CgH6S4)2] reveal enhanced anti-ferromagnetic interaction.
