Multistep redox sequences of azopyridyl (L) bridged reaction centers in stable radical complex ions (μ-L)MCl(η5-C5Me5)2$\surd$+, M = Rh or Ir: Spectroelectrochemistry and high-frequency EPR spectroscopy. Dalton Transactions, 17:3370--3375, 2003. [PUMA: ESR azopyridyl azopyrimidine azopyrimidinyl bridged bridged;spectro cation cyclopentadienyl electrochem ion iridium pentamethylcyclopentadienyl prepn;radical radical rhodium]