SYNTHESIS AND CHARACTERIZATION OF NITROXIDE-LINKED RUTHENIUM COMPLEXES AS MOLECULAR PROBES FOR MICROHETEROGENEOUS ENVIRONMENTS

Several new TEMPO (2,2,6,6-tetramethylpiperidine N-oxide)-labeled ruth enium complexes were prepared. They can be discerned in two different classes featuring rigid and flexible linkers between the ruthenium(II) -polypyridyl complex and the stable nitroxide. The bis(heteroleptic) r uthenium complexes were synthesized from [Ru(L(2))]Cl-2 (L = 2,2'-bipy ridine or 1,10-phenanthroline) and newly prepared phenanthroline-TEMPO -ligands. Finally, a tris(heteroleptic), spin-labeled ruthenium comple x has been prepared from [Ru(DMSO)(4)]Cl-2, dipyrido[3,2-a:2',3'-c]phe nazine (dppz), 1,10-phenanthroline and a phenanthroline-TEMPO-ligand w ith a rigid linker.