Coupling of organometallic reaction centers through the non-planar bridging ligand 2,3-bis(2-pyridyl)pyrazine. Zeitschrift fuer Anorganische und Allgemeine Chemie, (630)13-14:2409--2417, 2004. [PUMA: binuclear bis complex complex;mol complex;redox complex;rhodium crystal half iridium mononuclear pentamethylcyclopentadienyl potential prepn pyridylpyrazine rhodium sandwich structure]