<p>Tetraazamacrocycles, such as cyclam (1,4,8,11-tetraazacyclotetradecane), are useful
ancillary ligands in the formation of organometallic complexes. Coordination of
a 3d metal can lead to the formation of square planar complexes, such as with
Ni<sup>II</sup> and Cu<sup>II</sup>, or octahedral complexes upon coordination
of additional ligands, such as with Co<sup>II/III</sup> and Cr<sup>II/III</sup>.
Notably with Cr, a mixture of <i>cis-</i> and <i>trans-</i>octahedral
complexes are formed, and the isomerism can be influenced through <i>C</i>-substitution
of the cyclam macrocycle. Herein, Cr<sup>III</sup> complexes featuring <i>C</i>-substituted
cyclam derivatives and either redox-active ligands or alkynyl ligands are
reported.</p>
<p>Chapter 1 features an introduction
to the photophysical processes of Cr(III), an overview of cyclam and its
derivatives, and a brief review of Cr<sup>III</sup>(cyclam/cyclam’) bis-alkynyl
complexes for various applications. Chapter 2 discusses the structural,
optical, electronic, and magnetic characterizations of <i>cis</i>-[Cr(HMC)catecholate]<sup>+</sup>
and <i>cis</i>-[Cr(HMC)semiquinonate]<sup>2+</sup> complexes, which feature redox-active
catecholate and semiquinonate ligands. Chapter 3 highlights a series of <i>trans</i>-[Cr(HMC)(C<sub>2</sub>Ar)Cl]<sup>+</sup>
complexes, which expands upon prior research on bis-alkynyl complexes. Chapter
4 discusses how a different <i>C</i>-substituted cyclam derivative, MPC, is
used to produce <i>trans</i>-[Cr(MPC)Cl<sub>2</sub>]<sup>+</sup> starting
material in higher quantity than the HMC derivative. This allows for higher
amounts of <i>trans</i>-[Cr(MPC)(C<sub>2</sub>Ar)<sub>2</sub>]<sup>+</sup>
complexes to be synthesized, making it a more practical macrocycle for the
future pursuit of dissymmetric bis-alkynyl complexes.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/15025899 |
| Date | 21 July 2021 |
| Creators | Ashley Jo Schuman (11161362) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/THE_SYNTHESIS_AND_PHOTOPHYSICAL_CHARACTERIZATION_OF_MACROCYCLIC_CHROMIUM_III_COMPLEXES/15025899 |
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