MAGNETIC AND ELECTROCHEMICAL INVESTIGATIONS ON ANIONS DERIVED FROM OLIGOKETONES CONTAINING FLUORENONE AND BENZOPHENONE UNITS - AN APPROACH TO THE DESIGN OF STABLE MULTIRADICAL ORGANIC MATERIALS

The mono- and poly-anions of some mono-, di- and tetra-ketones contain ing fluorenone and benzophenone moieties have been studied by NMR and cyclic voltammetry, Alkali metal anion radicals of fluorenone, generat ed by electron transfer from an alkali metal naphthalene radical anion exhibit markedly lower molar paramagnetic solvent shifts than those g enerated by direct reduction with an alkali metal. Evidence is provide d for the involvement of hyperfine interactions between the naphthalen e and the paramagnetic solute. The dianion of the diketone 9 is parama gnetic as are the dianions of the tetraketones 6 and 7, The NMR data, combined with those obtained by cyclic voltammetry, indicate that poly ketones possessing fluorenone moieties connected through isophthaloyl 'spacers' are promising systems for the preparation of high-spin organ ics and electrophores.