3,6-Bis(2'-pyridyl)pyridazine (L) and its deprotonated form (L - H+)- as ligands for (acac)2Run+ or (bpy)2Rum+: Investigation of mixed valency in (acac)2Ru2(m-L - H+)0 and (bpy)2Ru2(m-L - H+)4+ by spectroelectrochemistry and EPR. Dalton Transactions, 4:706--712, 2005. [PUMA: bipyridine cyclometalated cyclometalated;spectroelectrochem crystal cyclometalated;mixed redox valence acac bispyridylpyridazine;electrochem structure ruthenium cyclometalated;EPR bispyridylpyridazine]