© 2017 The Royal Society of Chemistry. A series of group 8 metal complexes with the same molecular framework, [M(PY5Me2)L]n+ (M = Fe, Ru, and Os; PY5Me2 = 2,6-bis[1,1-bis(2-pyridyl)ethyl]pyridine; L = monodentate ligand), were successfully synthesized and structurally characterized. The spectroscopic and electrochemical properties as well as the catalytic activity for water oxidation of these complexes were investigated.