Synthesis,Structures And Magnetic Properties Of Cyanide Bridged 3d Metal Clusters

With the development of information age,the demand for high-density information storage is becoming stronger.Compared with the traditional inorganic magnetic material,the molecule-based magnets show unique superiority in size.Cyanide bridged metal cluster has attracted more and more attention because it shows a number of exciting magnetic functionalitics in the field of molecular magnetism.As the shortest diatomic bridging ligand,cyanide can propagate magnetic interactions.Characteristic linear coordination mode of cyanide provides the possibility for the modular and controllable synthesis of cyanometallates.By introducing different paramagnetic metal centers and ligands,the regulations of the structure and magnetic property of the compounds can be achieved.In this thesis,several novel zero-dimensional and one-dimensional cyanide-bridged metal compounds have been synthesized by the complexation of a series of widely used tricyanoiron building units together with 3d metal centers with different configurations.Their structures and magnetic properties were characterized:Four novel zero-dimensional cyanide bridged Fe-Co clusters were synthesized by using different tricyanoiron building units and tetrahedral coordination cobalt,formulated as {Co2Cl2(DMF)4[(Tp4-Me)Fe(CN)3]2}(1,Tp4-Me=hydridotris(4-methylpyrazol-1-y1)borate),(H3O+)@{Co4Cl4[(Tp4-Me)Fe(CN)3]4}(2),(MePh3P)4{Co6Cl6[(Tp4-Me)Fe(CN)3]6}·15CH3CN·3CH3OH-2H2O(3)and(BnEt3N)4{Co5Cl8-[(Tp*)Fe(CN)3]4}·4CH3CN·2H2O(4,Tp*=hydridotris(3,5-dimethylpyrazol-1-yl)borate).Notably,the hexagonal prism-shaped cluster 3 and the bis(trigonal bipyramidal)cluster 4 provide two novel molecular skeletons in the cyanometallate family.Furthermore,compund 1 behaved as a single molecule magnet under zero field with the effective energy barrier of 30.7 K.By introducing the polyoxometalates as large counterions into the synthesis of cyanide-bridges cluster,three hybrid compounds of cyanometalates and polyoxometalates were synthesized.They are[Co(DMF)3]6[(pzTp)Fe(CN)3]6-(HPMo12O4O)3(5,pzTp=tetrapyrazolylborate),[Co(TpEtOH)]4[(pzTp)Fe(CN)3]4-(HPMo12O4O)2·nDMF(6,TpEtOH=2,2,2-tris-(pyrazolyl)ethanol)and[{Co(CH3OH)4} {Co(CH3OH)3}2{(pzTp)Fe(CN)3}3][PMo12O40]·11.5CH3OH-H2O(7).Their successful synthesis showed that polyoxometalate anions can effectively regulate the structure of cyanide clusters.At the same time,it also provides the possibility of introducing polyoxometalate's own functions(such as catalysis,luminescence)to synthesize single-crystal multifunctional composite materials.Two one-dimensional pearl chain cyanide bridged metal clusters were synthesized by introducing cobalt ions with tetrahedral coordination and large counterions respectively.They are Co(DMF)4{(CoCl2)2[(Tp4_Me)Fe(CN)3]2}(8)and{[(Tp*)Fe(CN)3]2Ni2(DMF)8} {[(Tp*)Fe(CN)3]2Ni3(DMF)10(H2O)2}(PMo12O40)2(9).Compound 8 and 9 behaved as single chain magnets.