Syntheses And Properities Of Metal Organic Nanotube Materials Based On 3,6-Carbazole Dicarboxylic Acid

The independent 1D metal-organic nanotubes（MONTs）,assembled from metal ions or clusters and organic ligands,is a promising alternative because the principles of reticular chemistry can be applied for MONTs in a manner that is merely impossible for other 1D materials.However,the development of well-defined discrete MONTs is still in its infancy due to the inherent complexity and uncertainty in the self-assembly process.As a result,it is critical to investigate the assembly mechanism of MONTs material synthesis and optimize to increase the material performance through preliminary design.The organic ligand 3,6 carbazole dicarboxylic acid is chosen as the first ligand in this research to construct the metalloring clusters,a series of MONTs were prepared by reasonable methods.Furthermore,the strategies,such as inner surface functionalization,pore space partition and choosing higher nuclear metalloring clusters have been proposed to further discuss the relationship between structure and performance.Two novel anionic single-walled MONTs,FJU-105 and FJU-106 are achieved by employing[In₆（cdc）₆]⁶⁺metalloring clusters with the largest diameter as the SBUs.The inner surface of FJU-106 is functionalized by uncoordinated–COOH groups of the H-btc linkers,leading to higher proton conduction than FJU-105.At 70^oC,FJU-106 displays the proton conduction performances among MONTs,up to 1.80×10^-2 S cm^-1.And FJU-105and FJU-106 are the first examples of MONT proton conductors operating at subzero temperatures.The pore space partition（PSP）approach has been employed to realize novel MONTs（FJU-107）with dual functionalities for proton conductivity.By immobilizing cobalt clusters within the channels,the 1D hexagonal channels in the original FJU-106 have been partitioned into uniformly interconnected pore cavities,leading to the dramatically reduced channel apertures from 11.50 to 9.61（?）.FJU-107 displays the remarkable proton conductivity over a wide temperature range from-40 to 100°C under anhydrous conditions,at 100°C,reaches a maximum of 8.62×10^-3 S cm^-1.Moreover,the FJU-107 not only has a high proton conductivity of 3.82×10^-3 S cm^-1 at 95%RH and 50?°C but also maintains moderately high proton conductivity at a wide range of RH and temperature.Regulate the{In-O-In}_n building blocks by choosing different second ligands to enhance the stability and proton conductivity of MOFs.The compound FJU-103 formed by helix 6₅{In（OH）}_∞chain packing via the organometallic linker has a channel with abundant guest molecules,but the poor thermal stability hampers further application.The compound FJU-113 form by rare"chair"-shaped[In₂₄（μ₂-O₂cdc）₆（O₂C）₁₂（μ-OH）₁₈]metalloring-cluster connected with 5-sulfoisophthalicacid exhibits better hydrothermal stability than that of FJU-103,and displays the remarkable proton conductivity over a wide temperature range from-30 to 100°C under anhydrous conditions,at 100°C,reaches a maximum of 3.57×10^-3 S cm^-1.Moreover,the FJU-113 not only has a high proton conductivity of 2.41×10^-2 S cm^-1at 95%RH and 70?°C but also maintains moderately high proton conductivity at a wide range of RH and temperature.A rare high-nuclearity[Co₈（CO₂）₁₂Co₂₄（CO₂）₂₄（OH）₂₄Co₁₂（CO₂）₂₄（OH）₂₄（H₂O）₁₂]cluster-based three-dimensional MOFs（FJU-108）was woven by using cobalt nitrate,3,6carbazole dicarboxylic acid,and isophthalic acid 5-sodium sulfonate as raw materials.The44-core metal cobalt-oxygen cluster node in the structure is the first reported by bridging oxygen atoms from O₂,OH,and HCO₂ groups.At the same time,this is also the first case of 3d-MOFs constructed from high-nuclear metal cluster nodes.The compound FJU-108has good thermal stability,up to 260 ^oC;Magnetic analyses indicate that FJU-108 exhibits two types of spin-tilted antiferromagnetic properties,as well as spin flipping and small hysteresis at low temperatures.