Syntheses, structures, and magnetic properties of 3d-4f heterometallic complexes constructed from pyrazole-bridged CuIILnIII dinuclear units

A series of pyrazole-bridged heterometallic 3d-4f complexes, [CuDy(ipdc)(2)(H2O)(4)] center dot (2H(2)O)(H3O+) (1) and [CuLn(pdc)(ipdc)(H2O)(4)] center dot H3O+ (Ln = Ho (2), Er (3), Yb (4); H(3)ipdc = 4-iodo-3,5-pyrazoledicarboxylic acid; H(3)pdc = 3,5-pyrazoledicarboxylic acid), {[Cu(3)Ln(4)(ipdc)(6)(H2O)(16)] center dot xH(2)O}(n) (Ln = Sm (5), x = 8.5; Ln = Eu (6), x = 7; Ln = Gd (7), Tb (8), x = 9), have been synthesized and structurally characterized. Ligand H(3)ipdc was in situ obtained by iodination of ligand H(3)pdc. Complexes 1-4 are pyrazole-bridged heterometallic dinuclear complexes, and 2-4 are isostructural. Complexes 5-8 are isostructural and comprised of an unusual infinite one- dimensional tape-like chain based on pyrazole-bridged heterometallic dinuclear units. The magnetic properties of compounds 1-4, 7 and 8 have been investigated through the magnetic measurement over the temperature range of 1.8-300 K. (C) 2009 Elsevier B.V. All rights reserved.