The kinetics and stereochemistry of base hydrolysis of the seven isomers of [Co(dien)(ampy)Cl]2+ and [Co(dien)(ibn)Cl]2+

Common product distributions are observed for the capture of water and azide ion during the base catalysed substitution reactions of each of the four meridional isomers of [Co(dien)(ampy)Cl]2+ and [Co(dien)(ibn)Cl]2+. The constant syn/anti and cis/trans ratios pinpoint a common and unique pentacoordinate intermediate as shown.