The osma(II)cycles [Os(phpy)(LL)(2)]PF6 (LL = 1,10-phen (3a) and 4,4'-Me-2-2,2'-bpy (3b)) are made from [(eta(6)-C6H6)Os(mu-Cl)Cl](2) (1) either via transmetalation using the [Hg(phpy)(2)] organomercurial in MeOH or via the sp(2)-C-H bond cleavage of 2-phenylpyridine (phpyH) in MeCN to afford [(eta(6) -C6H6)Os(phpy)Cl] or [(eta(6)-C6H6)Os(phpy)(MeCN)]PF6, respectively. The latter two react cleanly with LL to give 3a and 3b, the M-II/III redox potentials of which equal 30 and -100 mV (vs Ag/AgCl), respectively. The electrochemically made Os-III species oxidize rapidly reduced glucose oxidase. The second-order rate constant equals 1.1 x 101 M-1 s(-1) for 3a at 25 degreesC, pH 7.