| According to the principle of coordination chemistry,indium metal organic frameworks have been investigated in this work focusing on synthesis method,crystal structure,luminescent properties and application as multi-functional materials.15 novel indiummetal organic frameworks have been hydro?solvo? thermally synthesized by varying the main ligands conjugated aromatic carboxylic acids from monocyclic,bicyclic,tricyclic to tetracyclic,and the auxiliary ligands o-phenylenediamine,2,2'-bipyridine and phenanthroline.The compositions and crystalline structures of these metal organic frameworks have been characterized by elemental analysis,single crystal and powder X-ray diffraction.The properties of these compounds are also investigated by TGA,fluorescence spectroscopy,UV-Vis spectroscopy and electrochemical workstation,which further reveal the relationship between structure and property.By choosing furan-2,5-dicarboxylic acid?H2FDA?as ligand,a novel 3D indium metal organic framework[In?FDA??HFDA??H2O?4]·2H2O?1?is achieved,which displays a supramolecular metal organic framework with 6-connected pcu topology driven by hydrogen bonding and ?···?stacking.Interestingly,the uncoordinated carbonyl group of 1 can sensitize Ln3+ions to obtain Dy3+@1 and Eu3+@1 materials for enhancing luminescence.When Eu3+concentration increased from 0.0 to 1.6?mol/L in aqueous solution,1 exhibits distinguishable luminescence color change from blue to red with fast detection time?<2 min?and the ratio of luminescence intensity at 617 nm to that at 408 nm(I617/I408)enhances linearly with a low detection limit of 0.87?mol/L.Additionally,careful adjustment of Ln3+ions,white-light emission material could be achieved with metal content of Dy0.87Eu0.13.In the following research introducing 2-quinolinecarboxylic acid?2-Hqlca?as main ligand and 1,2-diaminobenzene?OPDA?as auxiliary ligand,two indium metal organic frame works formulated as[In?2-Hqlca?2Cl3·3H2O]?2?and{[In?2-QLBM??2-qlca?Cl2]2·CH3CN·2H2O}?3?have been synthesized and characterized.2 possesses a?66?dia network with channel diameter about 0.19 nm,and 3 displays a?3,4?-connected topology network with the Schl?fli symbol of?63??65·8?,whose channel diameter is about 0.37 nm.Owing to large voids in the framework,3 can serve as a host for reversible encapsulating iodine corresponding to the 1.52 molecules of iodine per formula unit with fast response and high sensitivity.Moreover,absorption spectrum demonstrates the band gap of 3 is 3.58 e V.When adsorbing iodine into framework,the host structure of 3 is relatively perturbed by the presence of guests and exerts a remarkable influence on the band size and gap state.Subsequently by means of adding coordinate sites and extending conjugate system to change experiment conditions,selecting quinoline-2,3-dicarboxylic acid?2,3-H2qldc?as main ligand,1,10-phenanthrolin?phen?and 2,2?-bipyridine?2,2?-bipy?as auxiliary ligands,eight indium metal organic frameworks formulated as[In2?phen?3Cl6]·CH3CN?4?,[In2?phen?3Cl6]·CH3CN·2H2O?5?,[In2?phen?2Cl6?6?,[In?3-qlc?2?phen?Cl]?7?,[In?3-qlc?2?2,2?-bipy?Cl]·2H2O?8?,[In?3-qlc?3?phen?]·H2O?9?[In0.5K?3-qlc?Cl1.5?H2O?0.5]2n?10?and[In K?ox?2?H2O?4]n?11?are obtained.Due to existing hydrogen bonds forming coplanar dimers,7 and 8 show more extended?-conjugated system and display obvious aggregation-induced emission properties in the solid state.10 represents the chiral two-fold interpenetrating metal organic framework with right-handed helical chain along the 43 screw axis.Encouraged by the UV-visible absorption,10 displays an overall efficiency of 8.07%,which is22.09%higher than that of the device containing only N719?6.61%?.In order to further extend conjugate system,tris-?para-carboxylphenyl? phosphine oxide?H3TPO?is selected as ligand.Two topological types of{H[In3?TPO?2?OH?4]·2H2O}n?12?and[In?TPO?]n?13?are constructed.Increasing node connectivity as well as the trapping of guest OH–anions,5-fluorouracil?5-FU?is preferentially captured into the 12,which exhibits an outstanding loading capacity around 34.32 wt%.19F NMR spectroscopy is further employed to investigate host-guest interaction and reveals the binding constant?Ka=3.84×102L/mol?.Meanwhile,the controlled release of 5-FU in a simulated human body with liquid phosphate-buffered saline solution by bio-friendly Zn2+-triggered is realized.With an elevated Zn2+concentration,the drug release will be enhanced.Focused on increasing the number of carboxylic acid,1,3,5-tri?4-carboxyphenoxy?benzene is choosen as ligand to construct two metal organic frameworks,[In2?TCPB?2]·2H2O?14?and{[In3O?TCPB?2?H2O?3]OH}?15?.Yellow crystals 14 undergo humidity-induced structural transformation to yield deep red crystals 15,which could also undergo a reversible transformation into 14 driven by thermal dehydration.Notably,the color of 14 takes only 5 min changed under 58%relative humidity at 298 K,which is much quicker than that of common desiccant bluestone.When increased water content in the range from 0.0%to 0.2%in acetonitrile solvent,14 could rapidly detect trace amounts of water through turn-off luminescence sensing mechanism with a low detection limit of 2.95×10-6.In addition,15 displays excellent proton conductivity up to 2.84×10-4S cm-1at 298 K and 98% relative humidity. |
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