Two isoreticular metal–organic frameworks with CdSO4-like topology: selective gas sorption and drug delivery

Abstract

Two isoreticular metal–organic frameworks with chemical formulae [Cu(L)(4,4′-bipy)(H₂O)]_n 1.5nCH₃CN (1) and [Cu(L)(4,4′-bipy)(H₂O)]_n·4nH₂O (2) (H₂L = diphenylmethane-4,4′-dicarboxylic acid) were synthesized and structurally characterized. They show the CdSO₄ (6⁵ 8) net and have an obvious 1D channel that is spread along the crystallographic c axis. More importantly, 1 shows high selectivity for H₂ over N₂ and CO₂ at low pressure, which could be confirmed via computational calculations using the Connolly algorithm to reveal the size and shape of accessible voids. The incorporation of the drug 5-fluorouracil (5-FU) into the desolvated 1 was around 27.5 wt% per gram of the dehydrated 1. 5-FU is released in a highly controlled and progressive fashion with 61% of the drug released after 95 hours. In addition, we have applied molecular docking calculations to investigate the preferred conformation of 5-FU molecules upon binding to MOF 1. These calculations provide a structural basis to explain the 5-FU release from MOF 1.