3D heterometallic (3d-4f) coordination polymers: A ferromagnetic interaction in a Gd(III)-Cu(II) couple

Four 3d-4f heterometallic coordination polymers, [CU3(IDA)(6)Ln(2)] center dot n(H2O) [IDA = iminodiacetate dianion; Ln = Gd, n = 3 (1); Ln = Nd. n = 6 (2); Ln = Sm, n = 6 (3)] and [Cu(Cl)(NTA)Sm(H2O)(6)] center dot(ClO4) center dot (H2O) (4) [NTA = nitrilotriacetate trianion], have been synthesized and characterized by single crystal X-ray diffraction analysis. Complexes 1-3 are isomorphous, showing a 3D coordination framework having tubular channels filled by lattice water molecules running parallel to the c axis. Whereas complex 4 is a 1D polymer of alternating copper and samarium ions connected by NTA, and the chains get involved in H-bonding interactions resulting in a 3D network. A low temperature magnetic study reveals ferromagnetic interactions for complex 1. Thermogravimetric and X-ray powder diffraction analyses of 1, 2 and 3 show that the covalently bonded 3D network remains almost unaffected after deaquation. (c) 2007 Elsevier Ltd. All rights reserved.