Metal -organic porous frameworks designed from zinc(II), terbium(III), europium(III), and organic carboxylate building blocks.

Abstract

The body of this thesis focuses on constructing novel, metal-organic open framework (MOF) materials by the copolymerization in solution of Zn(II), Tb(III) Eu(III) metal ions with the organic building blocks: acetylenedicarboxylic acid (ADC), 4,4<super>'</super>-bipyridine (BPY), 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), 2,6-naphthalenedicarboxylic acid (NDC), 4,4<super>'</super>-azodibenzoic acid (ADC), 1,3,5,7-adamantanetetracarboxylic acid (ATC), and 1,4-benzenedicarboxylic acid (BDC). Several new open structures with the formulas Th(BDC)(NO₃)&middot;[HCON(CH₃)₂]₂ (MOF₆), Th₂(BDC)Y(H₂O)₄ (MOF-7), Tb₂(ADC)₃&middot;(CH₃OH)₂[(CH₃)₂SO]₂ (MOF-8), Tb₂(ADB)₃&middot;[(CH₃)₂SO]₂₀ (MOF-9), Zn(ADC)₂&middot;[BN(CH₂CH₃)₃]₂ (MOF-10), Zn₂(ATC)&middot;(H₂O)₂(CH₃Ch₂OH)₂ (MOF-12), and Zn(NDC)&middot;(H₂O)[HCON(CH₃)₂](C₆H₅Cl)_0.5 (INSOFAR) have been characterized through single crystal x-ray diffraction. Other non porous crystal structures have also been characterized: Zn(ADC)(H₂O)[HCON(CH₃)₂], Eu(NO₃)₄ (BPY)(HBPY), and Tb(HEDP)₂(C₅H₅N), and the preparation of these structures have been compared to the synthesis of the porous structures. In addition, the properties, porosity, and inclusion chemistry of the MOFs have been explored by gas and liquid sorption, thermal gravimetric analysis, elemental analysis, Fourier transform infrared spectroscopy, and x-ray powder diffraction techniques. Several challenges in the area of MOF materials have been addressed in this work. By using solvo-thermal and room temperature vapor diffusion techniques, effective methods of synthesis and crystallization have been developed for these systems. By using the large amount of data available on Zn(II) chemistry, as well as the work of previous researchers in our group, many novel Zn(II) - carboxylate open frameworks can now be designed for certain structural attributes. This is accomplished through using known atom clusters or secondary building units (SBUs) of the metal ion employed in constructing the framework. Furthermore, by implementing this design technique, SBUs can be utilized to minimize the amount of interpenetration that occurs within these structures. Finally, the lanthanide metals, Tb(II) and Eu(II) were used to design in functionality into the framework structures. The unique fluorescence of many of the lanthanides in the visible region can be used to create open framework sensor materials.