Title page for ETD etd-07032012-110851

Type of Document Dissertation
Author Cherutoi, Jackson Kiplagat
Author's Email Address jcheru1@lsu.edu
URN etd-07032012-110851
Title Beta-Diketone and Beta-Ketoenamine Based Molecular Squares
Degree Doctor of Philosophy (Ph.D.)
Department Chemistry
Advisory Committee
Advisor Name Title
Maverick, Andrew Committee Chair
Nesterov, Evgueni Committee Member
Spivak, David Committee Member
Stanley, George Committee Member
Griffin, Gregory Dean's Representative
  • Beta-diketones and beta-ketoenamine molecular squa
Date of Defense 2012-03-08
Availability restricted

This dissertation focuses on synthesis of β-diketone and β-ketoenamine ligands for molecular polygons. Previous work with the bis(β-diketone) m-pbaH2 showed that it can be converted to a copper molecular square, Cu4(m-pba)4, but its use in host-guest reactions was limited by its low solubility in most organic solvents. Accordingly, in the present work, the m-pbhxH2 ligand, with pentyl chains replacing the methyl groups in the β-diketone moieties of m-pbaH2, was successfully prepared beginning with 6-dodecyne. This ligand reacts with Cu2+ to make the molecular square Cu4(m-pbhx)4, which is soluble in a wider range of solvents. Host-guest reactions of Cu4(m-pbhx)4 with a variety of guest molecules were studied. The structures of the “empty” square, [Cu4(m-pbhx)4(CH3OH)2], and its adducts with several guest molecules, were determined by single crystal X-ray analysis. In these host-guest adducts, the Cu---Cu distances range from 13.7-15.1 Ĺ.

As part of a study of the effects of substituents on the properties of the resulting molecular squares, the 2-MeO-m-pbaH2 ligand had been prepared previously. This dissertation reports an improved synthesis of 2-MeO-m-pbaH2, and its larger homolog 2-MeO-m-pbprH2 was synthesized as well. Treatment of 2-MeO-m-pbprH2 with Cu2+ afforded a molecular square that is soluble in chloroform and dichloromethane. Treatment of the square with guest molecules did not yield adducts, most likely because of steric interference from the internal methoxy groups.

The two ligands m-pbaH2 and m-pbprH2 were converted to their ketoenamine analogs m-pbiH2 and m-pbpriH2 through microwave-assisted synthesis. The molecular squares Cu4(m-pbi)4, Cu4(m-pbpri)4, and Ni4(m-pbpri)4 were prepared from these ligands and characterized by single crystal X-ray analysis, UV-Vis spectroscopy, and cyclic voltammetry.

Two new bis(β-diketone) ligands based on triphenylamine were prepared for the first time. The new ligands were designed to make Cu(II) molecular squares that are larger (Cu---Cu ca. 21 Ĺ) than Cu4(m-pba)4 and its derivatives.

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