Probing Mixed Valence in a New tppz-Bridged Diruthenium(III,II) Complex (μ-tppz)Ru(bik)Cl23+ (tppz = 2,3,5,6-Tetrakis(2-pyridyl)pyrazine, bik = 2,2'-Bis(1-methylimidazolyl)ketone): EPR Silence, Intervalence Absorption, and nCO Line Broadening. Inorganic Chemistry, (46)9:3736--3742, 2007. [PUMA: ESR IR UV charge electrochem methylimidazolylketone methylimidazolylketone;intervalence methylimidazolylketone;ruthenium mixed oxidn prepn pyridylpyrazine redn ruthenium transfer transition valent]