Metal-organic frameworks based on iron oxide octahedral chains connected by benzenedicarboxylate dianions

Three new iron benzenedicarboxylates have been synthesized by solvothermal techniques, and their structures determined from single crystal X-ray data: Fe(OH)(BDC)(py)(0.85) (1), Fe(BDC)(DMF) (2), and Fe(BDC)(py)(0.42)(DMF)(0.25) (3) (BDC = 1,4-benzenedicarboxylate, py = pyridine, DMF = N,N-dimethylformamide). Compounds I and 2 are the Fe(III)- and Fe(II)-structural analogs of the known Cr benzenedicarboxylate compound (MIL-53). Both contain trans comer-sharing FeO6 octahedral chains connected by benzenedicarboxylate dianions. Compound 3 contains chains of iron oxygen octahedra that share both corners and edges. Each chain is linked by BDC to six other chains to form a three-dimensional framework. Crystal data: 1, space group I2/a, a = 6.889(2), b = 11.073(3), c = 18.280(6) angstrom, beta = 92.6(1)degrees; 2, space group Pn2(1)a, a = 19.422(2), b = 7.3022(5), c = 8.8468(7) angstrom; 3, space group P2(1)/n, a = 9.234(2), b = 17.243(3), c = 9.978(2) angstrom-beta = 93.9(1)degrees. (c) 2005 Elsevier SAS. All rights reserved.