Structures And Properties Of New Metal-organic Frameworks Constructed From Aromatic Carboxylic Ligands And Main Group/Transition Metals

Metal-organic frameworks have become one.of the hottest fields of material science due to their novel topologies,unique properties and potential applications in the fields of adsorption,sensor and photo/electrical materials.Aromatic carboxylic acid or N-containing aromatic carboxylic acids have been widely used in the construction of metal-organic frameworks owing to their functional properties and versatile coordinated models.Besides,main group metals can easily loss electronics to become metal ions with large radius,they also exhibit strong polarization and deformation ability,which have been extensively adopted in functional materials.The construction of aromatic carboxylic acid-main group metal framework will give rise to the production of new functional materials.In this thesis,aromatic carboxylic ligands including 2,5-pyridine dicarboxylic acid,2,6-pyridine dicarboxylic acid,4-(1-imidazolyl)benzoic acid,thiophene dicarboxylate were used to react with Ⅳ,VA main group metals(Bi,Pb,In)and some transition metal salts to generate 17 new metal-organic frameworks under the hydrothermal/solvent thermal conditions.Their structures were determined by X-ray diffraction analysis method,and furthermore characterized by IR,UV-Vis spectra.And the third order nonlinear optical properties were also tested.The molecular formula are listed as follows:(2,6-pydc=2,6-pyridinedicarboxylic acid;Tda = 2,5-thiophenedicarboxylic acid;Oda=octane diacid;Bipy=pyridine;IMBA=4-(1-imidazolyl)benzoic acid)Structural analyses show that these main group/tranisition metal-organic framewotk exhibit a wariety of structural diversity from 0-3D,and versatile intta/inter-molecular hydrogen bonds can be found.Specially,compound 1 is two-dimensional layer based on carboxylic acid and iodine ion(I3-I2)-bridge,which is a unique structure possessing good sensitivity.Compound 2 can translate into compound 3 by the loss of a I2 molecule,which illustrating thermal-induced single crystal to-single crystal transformation behavior.Compound 8 is an interesting three-dimensional structure with pore size of 2.068×2.738 nm.In the heavy main-group metal-organic frameworks,the metal centers all exhibit stereochemical activities of ns2 lone pair.Compound 14 can translate into 15 after heating,which exhibits interesting single crystal to single crystal translation behavior.Compound 16 can possess good flexibility due to the flexible ligand of octane diacid.Some compounds illustrate third order nonlinear optical activities with nonlinear absorptive indexes of 10-5 M/W.This work will provide theoretical guide for new functional metal-organic frameworks.