To a RBF flushed with nitrogen add 1.3 g of salen and 7 mL of degassed ethanol with stirring and heating until dissolved. Then prepare a hot solution from 1.2 g of cobalt(II) acetate suspended in 10 mL of ethanol and start addition of it to the RBF over the course of 15 minutes. Stir well with flushing of nitrogen. Cool down, filter and wash with some cold water. Store under inert gas.
Addition of the cobalt acetate suspension
Filtration and washing
The dry product