Syntheses, crystal structures and properties of two novel lanthanide–carboxylate polymeric complexes

Abstract

Two novel lanthanide–carboxylate polymeric complexes containing nine-coordinate lanthanide metal centers, [Nd(H₂btec)_1/2(btec)_1/2(H₂O)]_n (1), [Gd(Hbtec)]_n (2), have been prepared by hydrothermal reaction of NdCl₃·6H₂O or Gd(NO₃)₃·6H₂O with 1,2,4,5-benzenetetracarboxylic dianhydride. Complex 1 crystallizes in triclinic space group P, with a = 6.3822(5), b = 9.3323(7), c = 9.5201(7) Å, α = 88.422(2), β = 74.446(2), γ = 76.647(10)°, V = 531.13(7) ų and Z = 2. Complex 2 crystallizes in triclinic space group P, with a = 7.2325(7), b = 7.9946(8), c = 8.7833(9) Å, α = 65.4120(10), β = 86.272(2), γ = 84.377(2)°; V = 459.42(8) ų and Z = 2. The two complexes have high thermal stability and are stable up to 400 °C. Magnetic susceptibility measurements for 1 and 2 are consistent with the occurrence of antiferromagnetic interactions through carboxylate bridges.