Title page for ETD etd-09132010-142256

Type of Document Dissertation
Author Motegi, Hirofumi
URN etd-09132010-142256
Title Synthesis and Characterization of Crystalline Coordination Networks Constructed From Neutral Imidazole Containing Ligand and Rigid Aromatic Carboxylate
Degree PhD
Department Chemistry
Advisory Committee
Advisor Name Title
Hanson, Brian E. Committee Chair
Merola, Joseph S. Committee Co-Chair
Brewer, Karen J. Committee Member
Cox, David F. Committee Member
Marand, Hervé L. Committee Member
  • metal-organic frameworks
  • mixed ligand
  • solvothermal synthesis
  • imidazole
  • aromatic spacer
Date of Defense 2010-09-01
Availability unrestricted
The work is focused on the investigation of synthesis and structure of crystalline coordination networks by combining first a row transition metal ion with one anionic and one neutral bridging ligand. In the field of crystalline coordination networks, the goal is to synthesize porous 3D crystalline coordination networks with molecular sized cavities. The materials are characterized by XRD and TGA. It is important to understand the structural topologies to develop practical applications, such as gas storage, gas separation, and catalysis.

The bi- and tetra- dentate flexible imidazole ligands, 9,10-bis(imidazol-1-ylmethyl)anthracene (Chapter 2) and 1, 2, 4, 5-tetrakis(imidazol-1ylmethyl)benzene (Chapter 3), are synthesized and used as linkers to construct 1D, 2D, and 3D crystalline coordination networks with cobalt(II) or zinc(II) cations and H3BTC anions under solvothermal conditions.

Two 1D chain networks, [M(HBTC2-)(C22H18N4)(H2O)2]•H2O, are constructed from M(Zn(II) or Co(II)), H3BTC, and 9,10-bis(imidazol-1-ylmethyl)anthracene (Compound 2.1 and 2.2). These two 1D zigzag chains are linked into infinite 2D sheets by inter-chain π•••π stacking and hydrogen bonding.

Two 2D and one 3D cobalt(II) coordination networks are constructed from the tetradentate imidazole ligand and H3BTC. Compound 3.1 has a 2D corrugated sheet structure that is linked by inter-layer π•••π stacking and hydrogen bonding. Compound 3.2 has a 2D sheet structure. These sheets are interconnected by hydrogen bonds at the free acid group of the HBTC2- ligand. Compound 3.3 forms a two fold interpenetrated 3D network structure. Void spaces in the structure are filled with six water molecules.

Six 3D cobalt (II) coordination networks are constructed with bidentate rigid imidazole containing neutral ligands, 1,4-bis(imidazol-1-yl)benzene(L1), 1,4-bis(imidazol-1-yl)naphthalene(L2), and 9,10-bis(imidazol-1-yl)anthracene(L3), and H2BDC or H3BTC anion (Chapter 4). In 4.1-4.3, L1-L3 affects on degree of interpenetrations constructed with H2BDC ligand. In 4.1 and 4.2 are interpenetrating 3D networks with no accessible void space. In 4.3, void spaces of 3D networks are filled with 2D sheets. Compounds 4.4-4.6 are prepared by different concentrations of starting materials and different solvents. In 4.4-4.6, L3 serves as a pillar building block to construct 3D networks by applying with H3BTC ligand. The solvent exchange experiment for 4.4 is further discussed.

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