Solvent‐Regulated Formation of Metal/Metal‐Oxo Nodes in Two Indium Metal‐Organic Frameworks: Syntheses, Structures, Selective Gas Adsorption and Fluorescence Sensor Properties

Abstract

Two water‐stable indium metal‐organic frameworks, (NH2Me2)3[In3(BTB)4]·12DMA·4.5H2O (In‐MOF‐1) and (NH2Me2)9[In9O6(BTB)8(H2O)4(DMSO)4]·27DMSO·21H2O (In‐MOF‐2) (BTB = 4,4¢,4¢¢‐benzene‐1,3,5‐tribenzoate) with 3D interpenetrate structure has been constructed by regulating solvents. Structure analysis revealed that In‐MOF‐1 has a three‐dimensional (3D) structure with a single metal core, while In‐MOF‐2 features an octahedron cage constructed by three kinds of metal clusters to further form a 3D structure. The fluorescence investigations show that In‐MOF‐1 and In‐MOF‐2 are potential MOF‐based fluorescent sensors to detect acetone and Fe3+ ions in EtOH or water with high sensitivity, excellent selectivity, recyclability and a low detection limit. Moreover, the fluorescence mechanisms of In‐MOF‐1 and In‐MOF‐2 toward acetone and Fe3+ ions were further explained. In addition, In‐MOF‐2 has higher thermal and framework stability than In‐MOF‐1. The activated In‐MOF‐2 presents a high BET surface area of 998.82 m2g‐1 and a pore size distribution of 8 to 16 Å. At the same time, In‐MOF‐2 exhibits high selective CO2 adsorption for CO2/CH4 and CO2/N2, respectively. Furthermore, the adsorption sites and adsorption isotherms were predicted using Grand Canonical Monte Carlo (GCMC) simulations, and the adsorption energy of the lowest‐energy adsorption configuration was calculated using molecular dynamics (MD) simulations.