in benzene Co-complex was dissolved in benzene and allowed to decompose at room temp. under N2; filtered, solvent was removed under vac., residue was chromd. on silicagel using petroleum ether as eluant, crystd., sublimed at room temp. and < 0.001 mm; elem. anal.;

in THF-d8 (tetrahydrofuran-d8) each Co-complex was dissolved in THF-d8, cooled to -40°C and mixed; monitored by NMR at -50°C;