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

Abstract

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 1 and 2 are the Fe(III)- and Fe(II)-structural analogs of the known Cr benzenedicarboxylate compound (MIL-53). Both contain trans corner-sharing FeO 6 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 I 2 / a , a = 6.889 ( 2 ) , b = 11.073 ( 3 ) , c = 18.280 ( 6 ) Å , β = 92.6 ( 1 ) ° ; 2, space group P n 2 1 a , a = 19.422 ( 2 ) , b = 7.3022 ( 5 ) , c = 8.8468 ( 7 ) Å ; 3, space group P 2 1 / n , a = 9.234 ( 2 ) , b = 17.243 ( 3 ) , c = 9.978 ( 2 ) Å , β = 93.9 ( 1 ) ° .