Systematic structural modifications of copper(II) -based molecular magnetic materials

David James Nelson, University of Texas at El Paso

Abstract

Because of the increasing roles that molecular solid-state based magnetic materials are fulfilling in today's technological environment, it is necessary to understand the relationships between these material's syntheses and structures. This work addresses this problem by inducing systematic synthetic changes in molecular solid-state magnetic materials utilizing organic molecules as templates to effect particular coordination spheres in Cu(II) clusters. The materials' magnetic properties are examined due to the information obtained concerning other novel properties, such as semiconductivity and superconductivity, as well as the non-destructive nature of a magnetic analysis. These analyses are then studied to give clues as to the materials' synthetic-structural relationships. All of these complexes consist of an organic sublattice and a Cu(II)-based inorganic sublattice, so chosen since the d$\sp9$ nature of the Cu(II) ion allows quantum magnetic exchange phenomena to be examined, allowing a more direct investigation of the material's structure-property relationships.^ The solid-state materials investigated in this work are classified and discussed in terms of the long-range dimensionalities that their inorganic sublattices exhibit (i.e. zero-, one-, and two-dimensional structures). The zero-dimensional structures are comprised of relatively isolated Cu(II) clusters and were found to manifest themselves as monomers, twisted bibridged dimers, and monobridged quasi-linear trimers. Each example presented in this work was created for different materials-related objectives and possess different properties, depending upon their dimensionality. Multiple complexes comprised of one-dimensional magnetic lattices have also been examined, with one system in particular, $\rm(melH\sb2)\sb2CuCl\sb6$ (mel = melamine), crystallizing as two air-sensitive polymorphs, which differ in the degree of chain linearity. Only the polymorph exhibiting symmetry-induced chain linearity has been synthesized in sufficient quantity to allow magnetic studies. One of the more notable successes of this research effort in terms of predicting a material's properties from its synthesis are the two-dimensional perovskite-type compounds $\rm(RC\sb6H\sb4NH\sb3)\sb{x}CuCl\sb4.$ Based on previous studies with alkyl-based magnetic materials, it is shown that the derivitization of the anilinium ion in the para-position results in two-dimensional layers of CuCl$\sb4\sp{2-}$ ions with the counterions sandwiched between the layers, acting as spacer molecules. The magnetostructural relationships of most of the aforementioned complexes, as well as future pertinent studies, are also discussed. ^

Subject Area

Chemistry, Inorganic|Physics, Condensed Matter|Engineering, Materials Science

Recommended Citation

Nelson, David James, "Systematic structural modifications of copper(II) -based molecular magnetic materials" (1998). ETD Collection for University of Texas, El Paso. AAI9832819.
http://digitalcommons.utep.edu/dissertations/AAI9832819

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