Lonothermal Synthesis Of Open-framework Manganese Phosphates/Phosphites And Manganese Borophosphates

Inorganic open-framework compounds with regular pore architectures, variouschemical composition and rich structure diversity, have exhibited importantapplications in adsorption, separation, catalysis and so on. The synthesis of novelopen-framework compounds has become an important research subject in the field ofporous material science. With the development of synthetic technology, theconstituent elements of the skeleton of open-framework compounds have beenexpanded from the main group to transition metal atoms. With the introduction oftransition metal into the framework, some compounds with novel optical, electric andmagnetic properties have been reported, thus arousing widespread interest of theresearchers.Inorganic open-framework compounds are usually synthesized underhydrothermal or solvothermal conditions. The ionothermal synthesis with ionicliquids instead of water or organic solvents provides a new strategy for the synthesisof novel inorganic open-framework materials. Ionic liquid is nontraditional moltensalt comprising of anion and cation. Ionic liquid can not only act as solvent, but alsocan act as a template or precursor in the ionothermal synthesis of inorganic materials.Compared with traditional hydro/solvotherma synthesis, the ionothermal synthesisexhibits some excellent characters, such as low melting point, high boiling point,recycling use and so on. This thesis focuses on the ionothermal synthesis ofopen-framework manganese phosphates, manganese phosphites, manganeseborophosphates and so on. Main achievements include:1. The first open-framework manganese phosphate with DFT zeolite topologyhas been synthesized under ionothermal conditions. A manganese phosphate compound,[NH3(CH2)2NH3][MnPO4]2, denoted as JIS-14, has beenionothermally synthesized by using a eutectic mixture of dimethylaminehydrochloride and2-imidazolindone as the solvent and template-deliveryagent, which in situ yields ethylene diammonium cations (en2+) acting as thetemplate. There exists8-ring channel along the a, b and c direction,respectively. Protonated en2+cations act as the templates to compensate thenegative charge of the inorganic framework. This compound is the firstopen-framework manganese phosphate with zeolite topology.2. A novel open-framework manganese phosphate with12-ring channel hasbeen synthesized under ionothermal conditions. A novel open-frameworkmanganese phosphate compound,[NH3(CH2)2NH3][Mn2P2O7], denoted asJIS-13, has been ionothermally synthesized by using a eutectic mixture oftetramethylammonium chloride and2-imidazolindone as the solvent andtemplate-delivery agent, which in situ yields ethylene diammonium cations(en2+) as the template. There exists12-ring channel along the a direction.Protonated en2+cations act as the templates to compensate the negativecharge of the framework.3. A novel open-framework manganese phosphate [NH4]MnPO4(JIS-15) withlayer strcture has been synthesized under ionothermal conditions. JIS-15hasbeen ionothermally synthesized by the use of choline chloride and urea as aeutectic mixture solvent and template-delivery agent, which in situ yieldsNH+4as the template. NH+4cations act as the template to compensate thenegative charge of the inorganic framework.4. Two open-framework manganese phosphite compounds,(NH4)2Mn3(HPO3)4(JIS-16) and Mn(HPO3)(JIS-17), have been synthesized under ionothermalconditions and characterized by single crystal X-ray diffraction. Theframework structure of JIS-16is built up from MnO6octahedra and phosphitegroups, giving rise to a two-dimensional framework with NH+4cations fillingbetween the layers; the structure of JIS-17consists of a3-D condensedframework of edge sharing MnO6octahedra linked to [HPO3] units via oxygens. JIS-17is isostructural with the compound synthesized underhydrothermal condition reported in the literature. Magnetic measurementsshowed that strong antiferromagnetic interaction exists in JIS-16.5. Two open-framework borophosphates were synthesized under ionothermalcondition. An open-framework manganese borophosphate JIS-19with B/P to1/5has been ionothernally synthesized in the eutectic solvent composed ofcholine chloride and boric acid. JIS-19is formed by the connection of BO4tetrahedrons and manganese phosphate layers, and the DES acts as both thesolvent and reactant in the synthesis; A3D open-framework manganeseborophosphate JIS-19with B/P to2/5was ionothernally synthesized in theeutectic solvents composed of oxalic acid and benzyl trimethyl ammoniumbromide.6. Borogermanate JIS-20was synthesized under ionothermal system for the firsttime. JIS-20is constructed by alternate linkage of GeO4tetrahedra and B4O9clusters to form a zeotype framework with diamond topology. There exist9-ring and10-ring channels in this borogermanate. JIS-20is isostructural withthe compound synthesized under hydrothermal condition reported in theliterature.