Synthesis And Characterization Of Cyanide Bridged Fe₈ And FeCo Complexes With Spin Transition Behavior

Since 1996, the discovery of metal-to-metal electron transfer behavior in the Prussian blue analogue K0.14Co[Fe(CN)6]0.71·4.93H2O has attracted the chemists to do widespread research on new cyanido-based materials, due to the potential applications of such materials in switchable molecule-based information storage or electronic devices. In this thesis, we mainly introduced some complexes with the properties of spin crossover (FeⅡ8) )and intramolecular electron transfer (Fe-Co dimer).Recently, a lot of papers about FeⅡ compounds with spin crossover behavior have been published, including mononuclear, dinuclear, multinuclear,1 D chain and so on. In this thesis, we described the latest research progress of FeⅡ8 spin crossover compounds and Fe-Co dimer with intramolecular electron transfer.The main parts of this thesis described a series of cyanide-bridged cubic FeⅡ8 complexes determined by single-crystal X-ray diffraction, including A+(?)[Ph4P][(MeTp)4FeⅡ8(CN)12(Tpp)4]·(PF6)2·12DMF·4H2O (A= Na, K, Rb, Cs); A+(?)[Ph4P][(MeTp)4FeⅡ8(CN)12(Tpp)4]·(ClO4)2·12DMF·4H2O (A= Na, K, Rb, Cs), Ph4P = tetraphenylphosphonium, MeTp= methyltri(1H-pyrazol-1-yl)borate, Tpp= tri(pyridin-2-yl)phosphine, A+(?)[Ph4P][(pzTp)4FeⅡ8(CN)12(Tpp)4]·(PF6)2·12DMF·4H2O(A = Na, K, Rb, Cs) and Cs+(?)[Ph4P][(pzTp)4FeⅡ8(CN)12(Tpp)4]·(ClO4)2·12DMF·4H2O, pzTp = tetra(1-pyrazolyl)borate.Variable-temperature magnetic measurements revealed that all these Fe Ⅱ8 complexes underwent spin crossover, but there are still partial Fe(Ⅱ) atoms with high-spin state at low temperature, likely due to the existence of Na+, K+, Rb+, Cs+inside the cubes, which blocked the completeness of the spin crossover of these Fe8 cubes.At the same time, we have also characterized a FeⅢ-CoⅡ dimmer, [(Tp)Fe(CN)3Co(PY5Me2)](OTf)-2DMF, exhibiting an electron transfer from FeⅢLS-CN-CoⅡHS to FeⅡLS-CN-CoⅢLS, with the combination of SQUID magnetometry, IR and X-ray crystallography.