Organic high spin molecules, their metal complexation and mixed radical crystals

• Applicant: Professor Dr. Martin Baumgarten
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2002 to 2004
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5368836

This application aims at the synthesis of new high spin molecules which can be obtained via : · Ligation of stable organic high spin radicals to metal complexes either by nitrogen coordination or through the spin carrying units; · Synthesis of mixed solid neutral or radical ion salts. In this scope, as a new direction of our research we plan to concentrate our efforts on metal ligatable ligands bearing two or more radical centers. An important requirement here is that ligatable molecules should persist in high spin ground state, i.e. triplet or quartet. Nitrogen containing heterocycles such as pyridine, pyrazole, or even bipyrimidines carrying neutral stable spin centres like nitronyl nitroxides, nitroxides, or oxo-verdazyls should be used for ligation. Typical metal ions with one or more unpaired electrons as Cu2+ , Fe2+ and Mn2+ shall be tested for metal complexation. To predict the spin states of the above systems, quantum chemical calculations will be performed. AM1 with extended CI, band structure calculations and density functional theory will be employed for the organic radicals. For the metal complexes, density functional theory (DFT) with the B3LYP functionals has shown to produce very good results and will employed systematically.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1137: Molecular Magnetism
• Participating Person: Privatdozent Dr. Volker Enkelmann