CRC 858 B11 - Cooperativity in Inorganic-Organic Hybrid Systems: Steering of Magnetic Properties by Orientation of Radicals in Inclusion Complexes and at Surfaces (SFB 858)

Basic data for this project

Description

The design of organic magnetic materials based on stable radical molecules or molecule ions has received increasing interest. Recent research on a variety of nitroxide radicals and nitroxide radical salts revealed that the unpaired spins present in the crystal can exhibit ferromagnetic as well as antiferromagnetic properties. These magnetic properties might be tunable as a function of substituents present in the nitroxide molecules that influences the relative alignment of the nitroxide moieties within the molecule crystal. In general, these results match the McConnell model: Ferromagnetism may arise when the electron density between atoms overlaps with different phases of spin polarization. Up to now research focused on simpler molecule crystals or supramolecular assemblies thereof. Within project B11 we want to generate and characterize novel materials with cooperative magnetic properties via the specific alignment of organic radicals and radical ions in inorganic-organic hybrid systems. We are planning to incorporate the radical species into inclusion compounds. The relative alignment of the spin labeled atoms herein results from the relative alignment of the radical molecules. We also aim to attach radical species to surfaces via covalent bond formation as well as self assembly. The envisaged cooperative effects might be analyzed via measurement of magnetic susceptibility and further be characterized by field dependant curves of magnetism. Solid-state NMR techniques may also deliver a deeper insight.