A family of porous magnets, [M3(HCOO)6] (M = Mn, Fe, Co and Ni)

A family of porous magnets of [M-3(HCOO)(6)] (M = Mn, Fe, Co and Ni) with open diamond framework based on M-centred MM4 tetrahedral nodes, can be prepared by conventional solution chemistry method. They display permanent porosity, stability for thermal treatment, guest removal, and guest inclusion for a wide spectrum of both polar and non-polar guests of different size. The porous magnets show 3D long-range magnetic ordering and guest-modulated magnetic properties due to the subtle structure change of the magnetic framework that conforms to the guests and the nature of host-guest interaction. The dilution of [Fe-3(HCOO)(6)] framework by diamagnetic zinc ion results in a mixed-metal porous [FexZn3-x(HCOO)(6)] series showing gradual evolution from 3D long-range ordering to spin glass then superparamagnet and finally paramagnet. (c) 2006 Elsevier Ltd. All rights reserved.