| This dissertation presents experimental results from the synthesis and structural, magnetic characterization of representative low-dimensional molecule-based magnetic materials. Most of the materials reported in this dissertation, both coordination polymers and cuprate, are obtained as the result of synthesizing and characterizing spin ladder systems; except the material studied in Chapter 2, ferricenyl(III)trisferrocenyl(II)borate, which is not related to the spin ladder project. The interest in spin ladder systems is due to the discovery of high-temperature superconductivity in doped cuprates possessing ladder-like structures, and it is hoped that investigation of the magnetic behavior of ladder-like structures will help us understand the mechanism of high-temperature superconductivity.; Chapter 1 reviews fundamental knowledge of molecular magnetism, general synthetic strategies for low-dimensional coordination polymers, and a brief introduction to the current status of research on spin ladder systems. Chapter 2 presents a modified synthetic procedure of a previously known monomeric complex, ferricenyl(III)trisferrocenyl(II)borate, 1. Its magnetic properties were characterized and previous results have been disproved.; Chapter 3 investigates the magnetism of [CuCl2(CH3CN)] 2, 2, a cuprate whose structure consists of isolated noninterpenetrating ladders formed by the stacking of Cu(II) dimers. This material presents an unexpected ferromagnetic interaction both within the dimeric units and between the dimers, and this behavior has been rationalized based on the effect of its terminal nonbridging ligands.; In Chapter 4, the synthesis and magnetism of two ladder-like coordination polymers, [Co(NO3)2(4,4'-bipyridine) 1.5(MeCN)]n, 3, and Ni2(2,6-pyridinedicarboxylic acid)2(H2O)4(pyrazine), 4, are reported. Compound 3 possesses a covalent one-dimensional ladder structure in which Co(II) ions are bridged through bipyridine molecules.; Compared to the materials discussed in Chapter 3 and Chapter 4, Chapter 5 presents a strategy of synthesizing ladder-like structures in a distinctively different system, bimetallic cyanide-bridged Prussian Blue analogs. Calculations are designed and carried out to identify two potentially successful model structures which are subsequently attempted synthetically. The two model structures are [NiII(CN)4]3[FeIII(terpy)] 2 and [FeII(cyclam)2]3[Ni II(dpa)]2(CN)6.; Finally, in Chapter 6, four Cu(II)-based low-dimensional materials are reported. Two of them, Cu2(C2O4)(histamine) 2[N(CN)2]2, 5, and Cu2(C 2O4)(histamine)2(N3)2, 6, consist of dimeric structural units that assemble into two-dimensional sheets. Magnetically, both behave as an isolated dimer system. On the other hand, compound 7, [Cu4(4,4'-bipyrimidine) 2(N3)8]n has a two-dimensional covalent network structure that can be viewed as being formed by covalently bridging one-dimensional ladders. (Abstract shortened by UMI.)... |
