New magnetic behaviour of honeycomb layered compounds. Crystal structures of [M 2 (bipym)(N 3 ) 4 ](M = Co II , Fe II ; bipym = 2,2′-bipyrimidine)

A one-pot reaction of Co(NO3)2·6H2O or FeCl2, 2,2′-bipyrimidine (bipym) and NaN3 affords the two [M2-(bipym)(N3)4](M = CoII 1, FeII 2) honeycomb sheetlike compounds with alternating double end-on azide and bis(chelating) bipym bridging groups; magnetic susceptibility measurements indicate that they exhibit ferromagnetic (through the end-on azide) and antiferromagnetic (through bipym) magnetic interactions, their magnetization studies revealing the occurrence of metamagnetic like behaviour.