Syntheses, Structures And Properties Of Metal-organic Coordination Polymers Constructed From Polycarboxylic Acid

In recent years, metal-organic frameworks （MOFs, metal-organic coordinationpolymers） as a new generation of functional materials have attracted considerable attentionin academia and industry. It is for not only their intriguing topologies and a higher surfacearea compared to ‘classical’porous solids such as molecular sieve, but also the flexibletailor, the design, easy regulation of pore, decoration derived from the exsit of organicligands, and easy functional characteristics. It has an attractive prospect in the gas-storage,select adsorption and separation, fluorescence, electromagnetics, chiral separation andcatalysis field.Based on the principle of molecular engineering, we focused our research on thesynthesis conditions, reaction influencing factors （temperature, solvent, pH value, etc.）,structures and functional properties. The aims are to explore the diversified structure ofmetal organic coordination polymers and to examine the organic ligands of differentconfigurations and metal centers of the different coordination modes of to the role of thestructure. We summarize its own rules, and can realize progressively the metal-organiccoordination polymer materials of the semi-directional and directed synthesis.Polycarboxylic acid is to construct the ideal member of the metal-organic coordinationpolymers, since the ligands contain more than one carboxyl group. when the carboxylgroups are deprotonated, they can compensate automatically for the charge, thus avoidingthe alien anions effect on the structure. At the same time, the carboxyl groups haveversatile coordination modes, and they laid the foundation for the assembly of the complexstructure of the polymer. The lanthanide ions have particular4f outer layer electrons anddiversied coordination numbers, and the MOF_s constructed from lanthanide ions presentexcellent optical, electronic and magnetic properties. It is capable of forming a very stable coordination bond, and is easy to obtain good polymers of thermal stability. It is wellknown that the ability of the ligand of the transition metal elements are also very good, andhave excellent affinity for the majority of coordination atom, and the coordination numberchangeable, it is the hot research. In summary, in this thesis, the lanthanide ions and thetransition metal ions were selected as templates, and polycarboxylic acids were chosen aslinkers/counterions to construct metal-organic coordination polymers with novel andfascinating crystal structures. These complexes were characterized by elemental analysis,IR spectroscopy, and single-crystal X-ray diffraction. The thermal properties of somecomplexes and the properties of the part of the complexes were investigated.The main results are as follows:1. A series of novel coordination polymers [Ln2（NIPH）2（Suc）（H2O）2][Ln=Tb （1）,Eu （2）, Gd （3）, Dy （4）, Ho （5）, Er（6）, Tm （7）, Y （8） and Yb （9）; H2NIPH=5-nitroisophthalic acid; H2Suc=succinic acid] have been synthesized by the reaction ofnitrate salts of Ln （III） with5-nitroisophthalic acid and succinic acid under hydrother-malconditions and were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Structural analyses reveal that all nine complexes have3-Dstructures, and in these complexes, they were crystallized in monoclinic space group C2/c.Two crystallographically equivalent Ln atoms are bridged by two especial carboxylategroups in chelating/bridging bidentate fashion to give a dinuclear lanthanide building block[Ln₂O₂（CO₂R）₈] with shorter separations of Ln…Ln. Those blocks are interconnected toeach other leading to a1-D infinitely extending chain, and then these chains are linked toeach other through the NIPH to a2-D open framework, which further link to each other toform3-D networks. The thermogravimetric analysis of1–9and photoluminescentproperties of1and2are discussed in detail.2. By designing the novel ligand,3,3’-[（6-oxbydrl-1,3,5-triazine-2,4-diyl） diimino]dibenzoic acid （OTADDB） has been synthesized successfully. A novel coordinationpolymer [Cd（OTADDB）· C₂H₅OH·2DMF· H₂O]_n（10） has been obtained from OTADDB and Cd salts by low temperatures slow diffusion method and was characterizedby elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. The resultsshowed that complex10contains a three-dimensional frame structure constructed byOTADDB and metal Cd ion. Cd ions were respectively lined by the two N atoms and twooxygen atoms, forming a tetrahedron structure of at the center of Cd ion. And complex10shows8×11pore in the x-axis and y-axis direction, respectively.3. By designing the novel ligand,3,3’,3’’-（[1,3,5]-triazine-2,4,6-triyltriimino）tribenzoic acid （TATTB） has been synthesized successfully. Three novel coordinationpolymers Pr₂（TATTB）₂（DMF）₄5H₂O （11）, Nd₂（TATTB）₂（DMF）₄5H₂O （12）， andMn₃（TATTB）₂（DMF）₃（H₂O）6H2O （13） have been obtain from TATTB and correspondinglanthanide salts and transition metal salts by low temperatures slow diffusion method andwas characterized by elemental analysis, IR spectroscopy, and single-crystal X-raydiffraction. The results indicates that,（i） complexes11-12have the same crystal structureincluding a two-dimensional layered structure constructed by TATTB, DMF, and the rareearth metal ion. The DMF molecules extend outer layer and DMF molecules betweenlayers mutually support by hydrogen bonding to form a three-dimensional frame structure.In complexes11-12, Ln showed two kinds of different coordination environments withnine ligands and ten ligands of the surrounding oxygen atoms, respectively.（ii） Thecomplex13contains TATTB, DMF, H2O and transition metal Mn2+to build the two-dimensional layered structure.In this paper, a series of rare earth metal organic polycarboxylic acid coordinationpolymers and transition metal polycarboxylate complexes have been obtained usinghydrothermal method and low temperatures slow diffusion method. And synthesisconditions, methods, structures, and the corresponding properties were also beenelaborated in detail. The successful synthesis of the series of complexes, not only enrichthe types of metal-organic coordination polymer, but also for the study of the synthesis ofthe material law, directed the synthesis of related materials and the development of itsnature provides the necessary experimental basis.