Doctor Of Philosophy / Department of Chemistry / Christer Aakeröy / Crystal engineering, or non-covalent synthesis in the solid state, requires an
understanding of intermolecular forces, and the hydrogen bond has become a reliable
non-covalent tool in the construction of supramolecular architectures. In the same way
that synthetic chemists refer to a “yield” to quantify a desired product, crystal engineers
typically determine the successful formation of a supramolecular product according to the
frequency or occurrence of preferred intermolecular interactions between molecules
under certain reaction conditions, thus, the supramolecular yield. These non-covalent
reactions can be effectively carried out using supramolecular reagents (SR’s).
A family of ditopic bis-imidazol-1-yl/benzimidazol-1-yl compounds were synthesized
and used as SR’s in combination with a variety of dicarboxylic acids to produce binary
solids in 100% yield through the primary acid···imidazol-1-yl/benzimidazol-1-yl synthons
even in the presence of potentially disruptive intermolecular interactions. We
furthermore noted that secondary C–H···O interactions within and between 1-D chains
were of equal structural importance based upon an analysis of the metrics displayed by
these interactions. The use of these SR’s as ligands with neutrally charged metal
complexes was also investigated.
SR’s containing benzimidazol-1-yl and carboxamide moieties were synthesized and
combined with two different carboxylic acids to make ternary solids through
acid···benzimidazol-1-yl and carboxamide···acid hydrogen bonds using a hierarchical
approach – the best donor-best acceptor, second best donor-second best acceptor
guidelines. These SR’s were also employed as ligands for high-yielding syntheses of
linear metal complexes where neighboring complexes are linked via
carboxamide···carboxamide hydrogen bonds.
Asymmetric SR’s possessing two different N-heterocycles were synthesized and
employed in the construction of ternary supermolecules with a high degree of structural
selectivity and specificity when introduced to two different carboxylic acids. The
stronger acid interacts at the more basic site, while the weaker acid hydrogen-bonds with
the less basic nitrogen atom. Finally, an SR containing three different binding sites was
designed and synthesized with the aim of producing quaternary co-crystals.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/83 |
| Date | January 1900 |
| Creators | Urbina, Joaquin Francis |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
| Format | 2924308 bytes, application/pdf |
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