in octane Cr-complex and cyclohexa-1,3-diene in octane heated to 150°C; sublimed in vacuo;

hydrogen in ethyl acetate over Pd-coal;;

dihydrogen hexachloroplatinate; tin(ll) chloride; lithium bromide in ethyl acetate (Ar); addn. of soln. of tin compd. in ethyl acetate to mixt. of platinumcompd. and LiBr in ethyl acetate, introducing H2, stirring for 1 h, add n. of chromium compd.; addn. of 2 M aqueous HCl, separating organic layer, washing with water, drying, evapn., sublimation in vac.;