A Cu–Zn–Cu–Zn heterometallomacrocycle shows significant antiferromagnetic coupling between paramagnetic centres mediated by diamagnetic metal†
Abstract
An unprecedented antiferromagnetic exchange mediated by two –O–Zn–O– bridges, with singlet–triplet splitting J = 35.0 cm−1, was observed between two copper centers separated by 5.7062(9) Å in the heterometallomacrocyclic diethanolamine (H2L) complex [Cu2Zn2(NH3)2Br2(HL)4]Br2·CH3OH.