Cooperative magnetic behavior of α‐ and β‐manganese(III) phthalocyanine tetracyanoethenide (1:1), [MnIIIPc]·⊕[TCNE]·⊖

Cooperative magnetic interactions have been observed in α‐[MnPc][TCNE], which results from the reaction of manganese phthalocyanine with tetracyanoethylene. This is the latest in a series of molecule based materials found to exibit such unusual magnetic behaviour. The α polymorph displays very strong magnetic coupling, while the coupling in β‐[MnPc][TCNE] is much weeker. The IR data suggest that the behaviour of the α polymorph is unlikely to be unique among the metallomacrocyclic electron‐transfer complexes. It is proposed that uniformity of the one0‐dimensional chains in α‐[MnPc][TCNE] and the corresponding lack of uniformity of those in the β polymorph may give rise to the difference in behaviour.