Synthesis, Crystal Structure, And Magnetism Of Heterotrimetallic Complexes And Coordination Compounds Of V-shaped Carboxylic Acids

Coordination chemistry is an intercrossed branch between inorganic chemistry and organic chemistry, its investigation subject is coordination compounds (complexes). As a main exploration system, cyanide and carboxyl bridged metal-organic complexes have attracted extensive attentions due to their unique luminescence, gas absorption, magnetism, and catalysis properties, and so on. Therefore, the synthesis, characterization, and investigation on the property of these two kinds of compounds have been the focus in the field of coordination chemistry. Molecule-based magnetism is the hot research field, of which the basic content is to explore the relationship between the neighboring open-shell molecules or ions as spin carriers. There are two branch fields subordinate to the main research field, namely, intramolecular micro-magnetic behavior and macro-magnetic behavior of the molecule aggregates. The macromagnetic behavior is the expression form of the intramolecular magnetic action. The micromagnetism is the result of the spin carriers being influenced by the surrounding. These influences are mainly from the changes of coordination enviroment around the open-shell ions and their micromagnetic action between the spin carriers (magnetic coupling). Accoundingly, the design and synthesis of the new metal-organic complexes with novel magnetic topologies together with discovery of the new magnetic phenomena are the hot research issues, as well as exploration the possibilities of prediction and control for the magnetic topologies and magnetic properties. This thesis mainly concerns about the above mentioned hot issues to design and synthesize cyanide-bridged heterotrimetallic complexes with new magnetic topologies and coordination polymers constructed from semirigid V-shaped asymmetric carboxylic acid as well as to explore the relationship between magnetic propertiy and structure.In this thesis, the modified dicyanometallates K[M(L)CN2] [M= FeⅢand CrⅢ, L=bpb, Clbpb, and dmbpb] as precusors were used to react with the dinuclear metal complexes based on the ligands formed from 2-hydroxy-5-methyl-benzene-1,3-dicarbaldehyde and corresponding diamine. Five novel cyanide bridged heterotrimatallic compounds have been obtained including {[CuPb(L1)][Fe(bpb)(CN)2]}2·(ClO4)2·(CH3CN)2·(H2O)2 (1), {[CuPb(L1)] [Fe(Clbpb)(CN)2]}·(C1O4)·(CH3CN)·(H2O) (2), {[CuPb(L1)][Fe(bpb)(CN)2]}2·(ClO4)2·(CH3OH)2 (3), {[CuMn(L1)] [Fe(bpb)(CN)2]} n·(C104)n·(H20)n (4), {[CuMn(L1)][Cr(bpb)(CN)2]}n·(C104)n·(H20)n (5). The investigation on the synthesis, crystal structure, and magnetic characterization enrich the system of heterotrimetallic species and the experience to construct the heterotrimetallic compounds. The relastionship between the magnetic topology and the magnetic behavior has also been discussed, and the magnetic coupling between the neighboring metal ion s in the herterotrimetallic complexes has been analysized and explained according to the orbit theory.In addition, fourmultidentate O-donor ligands with three coordinating carboxylic groups attached at asymmetrical positions of a semirigid V-shaped central molecular framework has been applied to generate the magnetic materials, which have never been directly employed in the crystal engineering field. Using these four semirigid V-shaped multicarboxylate ligands with the help of a 4,4'-bpy secondary ligand, a series of four novel Co(II) coordination polymers with diverse molecular structures including [Co(HL1)(u,4'-bpy)(H2O)3]n·(4,4'-bpy)n-(H2O)2n (6), [Co1.5(L2)(u-4,4'-bpy)1.5]n·(4,4'-bpy)0.5n (7), [Co3(L3)(HL3)(OH)(H2O)2(u,4'-bpy)2]n·(H2O)2.5n (8), [Co1.5(L4)(u-4,4'-bpy)2(H2O)3]n(H2O)3n (9) has been obtained. The effect between the coordination molecular configurations of the carboxylic acid together with the asymmetric position on the molecular structure of the coordination polymers has been discussed. This is also true for the relationship between the linking mode of the carboxylic substituents and the magnetic properties. According to the easy model, the magnetic coupling between the neighboring metal ions has been evaluated.