Structure, hydrogen storage, and luminescence properties of three 3D metal-organic frameworks with NbO and PtS topologies

Three 3D multifunctional microporous metal-organic frameworks (MOFs), Cu-2(ABTC)(H2O)(2)center dot(DMF)(2)(H2O) (JUC-62), Cd)(2)(ABTC)(DMF)(3)center dot(DMF)(2) (JUC-63), and Mn(H(2)ABTC)(DMF)(2) (JUC-64)(H(4)ABTC = 3,3',5,5'-azobenzenetetracarboxylic acid, DMF = NN'-dimeihylformamide, and JUC = Jilin University China) have been synthesized by self-assembly of a rigid tetra-carboxylate ligand H4ABTC and corresponding transition metal salts under mild conditions. X-ray crystallography reveals that their topologies are based on NbO (JUC-62) and PtS (JUC-63 and JUC-64) nets, constructed of 4-connected rectangular ABTC(4-) units with 4-connected square paddle-wheel CU2(CO2)(4)(H2O)(2) secondary building units (SBUs), tetrahedral bimetallic Cd-2(CO2)(4)(DMF)(3) -)(4)(DMF)(3) SBUs, and tetrahedral monometallic Mn(CO2)(4)(DMF)(3) SBUs, respectively. High-pressure hydrogen sorption of the activated JUC-SBUs, 62 reveals a type I profile at 77 K, which is saturated at 40 bar with a hydrogen uptake of about 4.71 wt%. Photoluminescence investigations reveal that JUC-62 and JUC-63 display strong main emission spectra peaks at 392 and 402 urn, respectively.