Cobalt complexes homoleptic species

W. W. Brennessel, V. G. Young, Jr., and J. E. Ellis of the University of Minnesota, Minneapolis, synthesized the homoleptic bis(l,2,3,4-T " -anthracene)cobal-tate(l-) salt by reducing CoBr2 with potassium anthracene in tetrahydrofuran at -55 to -65 °C. A dark red solution resulted, from which deep red, nearly black microcrystals of the bis(anthracene)cobaltate(l-) were obtained in 82-87% yields. Although the analogous naphthalene complex is highly reactive (e.g., it readily reacts with carbon monoxide at normal pressure and at -60 °C to yield [Co(CO)4] , all attempts to isolate this interesting species have failed so far. Reduction of cobaltocene by three equivalents of potassium naphta-lene yielded a similarly labile source of Co ". Isolation and characterization of the homoleptic Co isonitrile complexes by other authors also encountered difficulties. ... 

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