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Design and Construction of Terpyridine-based Two-Dimensional and Three-Dimensional Supramolecular Architectures

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2013, Doctor of Philosophy, University of Akron, Polymer Science.
Supramolecular self-assembly focuses on the studies of weak interactions beyond molecules and construction of complicated, well-defined supramolecular architectures which widely exist in natural process and have been used in catalysis, chemical sensing and molecular electronics. Utilization of <tpy-MII-tpy> (M = metal) connectivity to construct specific shaped supramolecular architectures has been well-developed. Bisterpyridines possessing 60° and 120° directionality can readily form triangular and hexagonal metallomacrocycles with group 12 metals, such as: Zn(II) and Cd(II), respectively. The supramolecular rhomboidal architecture could also be formed through a multicomponent self-assembly utilizing a precise stoichiometric ratio (1:1:2) of bisterpyridines with 60° or 120° directionality and metal ions (Zn2+ or Cd2+). However, the triangular construct, which is formed solely by bisterpyridine with 60° branching angle, could also be detected in the same solution. To further probe the self-sorted formation of a rhomboidal architecture, a tristerpyridine possessing three adjacent terpyridine units is used. Such tristerpyridine ligand can readily react with 60°-directed bisterpyridine ligands and metal ions (Zn2+ or Cd2+) in the stoichiometric ratio (2:2:5) to quantitatively form a center-bridged, fused-triangular shaped, rhomboidal structure. A facile heteroleptic self-assembly of hexakisterpyridine and tristerpyridine possessing 60° angles between the adjacent terpyridine moieties with stoichiometric amount of Zn2+ ions (1:6:12) leads to the formation of supramolecular spoked wheel architecture in a 90% isolated yield, which is fully characterized by ESI-MS, NMR, and TEM imaging. When the central hexakisterpyridine of the spoked wheel is replaced with two staggered tristerpyridine ligands possessing 120° angle between the adjacent terpyridine units, a three-dimensional, supramolecular, bicycle-like wheel structure is readily formed, in which two 120°-directed tristerpyridines serve as the hub and spokes and six 60°-based tristerpyridines locate outside as rims. Another analogous supramolecular spoked wheel can also be formed by further redesign of the core ligand. Two tristerpyridine ligands possessing 60° between the adjacent terpyridine units adopt a parallel-staggered conformation with the opposite orientations to replace the core hexaligand. Eight equivalent amount of such tristerpyridine ligands (two serving as core ligands; six as outer rim ligands) can readily react with twelve equivalence of metal ions (Zn2+ or Cd2+) to form a supramolecular mandoline-shaped wheel structure, which contains two vertex-connected, centrally-bridged rhomboidal moieties at the concentration of > 15 mg·mL-1. When the concentration of the Cd2+-based mandoline-shaped structure is reduced, a quasi-tetrahedron structure possessing four tristerpyridine ligands and six Cd2+ ions can be detected and it becomes the only self-assembly product when the concentration is below 0.5 mg·mL-1. The Zn2+ analogue of the mandoline-shaped structure remains intact during the dilution and there is no quasi-tetrahedron structure detected in such supramolecular system.
George Newkome, Dr. (Advisor)
Chrys Wesdemiotis, Dr. (Committee Member)
Stephen Cheng, Dr. (Committee Member)
Li Jia, Dr. (Committee Member)
Kevin Cavicchi, Dr. (Committee Member)
174 p.

Recommended Citations

Citations

  • Lu, X. (2013). Design and Construction of Terpyridine-based Two-Dimensional and Three-Dimensional Supramolecular Architectures [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1375364176

    APA Style (7th edition)

  • Lu, Xiaocun. Design and Construction of Terpyridine-based Two-Dimensional and Three-Dimensional Supramolecular Architectures. 2013. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1375364176.

    MLA Style (8th edition)

  • Lu, Xiaocun. "Design and Construction of Terpyridine-based Two-Dimensional and Three-Dimensional Supramolecular Architectures." Doctoral dissertation, University of Akron, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1375364176

    Chicago Manual of Style (17th edition)