An Investigation into the Structure Directing Properties of Organic Templates with Mn, Fe and Cu

Author: Hewitt, Ian Göttingen, 11. March 2004 pages: 178 edition: 1 language: ISBN-10: 3865370160 ISBN-13: 9783865370167 allocated areas: Chemie source of supply Print Version 27,00 € 25.65 in the shopping basket eBook (14381.3 kB) 27 in the shopping basket

Kurzbeschreibung

The aim of this research was to synthesize transition metal aggregates in a variety of different shapes with potentially interesting properties. A variety of strategic methods was developed to achieve this. Firstly, a range of Schiff base complexes was investigated. This includes the design of Mn4 and Fe4 aggregates having structural motifs similar to known single molecular magnets. Subtle differences in the molecular structure for the Mn4 aggregates results in anti-ferromagnetic interactions giving a ground state of S = 5 or ferromagnetic interactions resulting in a ground state S = 10. The Schiff base stabilized the formation of a mixed-valence {FeII3FeIII} aggregate, for which initial measurements indicate the presence of a spin-crossover in the FeIII ions. Secondly, the research focused on the templated formation of nanosized iron oxide shaped compounds. This was first attempted by using macrocyclic ligands capable of controlling the growth of iron oxide/ hydroxides. Two macrocycles were successfully synthesized in 6 to 7 step reactions from the literature based upon their potential ability to accommodate an iron oxide core. Although these were observed to incorporate FeIII ions, the target compound has not yet been obtained.Finally, the directing effect of surfactant molecules with FeII during the hydrothermal formation of magnetite was studied. This resulted in the formation of a variety of new nano-sized magnetite species exhibiting unusual crystalline habits which were observed using electron microscopy. Some information about there composition has been obtained using energy-dispersive analysis of X-rays (EDX).