Ferrocene-chelating heteroscorpionate compounds based on [fc(PPh2)(BH[(3-R-5-R'-1-H)2pz]2)] (fc = 1,1'-ferrocenediyl, pz = pyrazole) are studied and characterized for their role in the synthesis of block copolymers. The ferrocene scaffold is part of a heteroscorpionate ligand that supports late transition metals. A zinc complex, [fc(PPh2)(BH[(3,5-Me-1H)2pz]2)]Zn(μ-OCH2Ph), was synthesized previously and shown to exist in a dimeric state. Herein, the substituents on the pyrazole fragments of the scorpionate are replaced with bulkier groups to force the formation of a monomeric compound in order to arrive at a redox switchable catalyst.

This work culminates a systematic study of various uranium complexes supported by ferrocene diamide ligands. Chapter 1 reports the synthesis of 1,1'-ferrocene diamines and describes their electronic and steric properties in both neutral and oxidized forms. Chapter 2 describes an efficient synthesis of uranium dialkyl complexes supported by a single 1,1'- ferrocene diamide ligand, while Chapter 3 explores their reactivity with several aromatic heterocycles. Chapter 4 focuses on the electrochemical behavior of ferrocene-based uranium halide, alkyl, aryloxide, and amide ligands. Finally, Chapter 5 explains electrochemical, spectroscopic, and magnetic properties of uranium bis(1,1'-diamidoferrocene) complexes in an attempt to establish how well uranium mediates electronic communication between two iron centers.

Ferrocene chelating ligands provide good stability of the resulting metal complexes and redox-switchable control in chemical processes catalyzed by those complexes. In comparison to traditional di-substituted ferrocene tetradentate ligands, mono-substituted tridentate ferrocene ligands may form metal complexes with a more open coordination sphere around the metal center that may allow an increased preference for substrate coordination. In addition, a mono-substituted ferrocene ligand allows the investigation of the through bond influence of the ferrocenyl group on catalytic metal centers by increasing the metal-iron distance. In this thesis, the design, synthesis, and characterization by 1H NMR spectroscopy of a novel mono-substituted ferrocene ligand are described. To explore its ability to support metal complexes with high activity and redox-switchable in polymerization reactions, yttrium alkoxide and aluminum alkyl complexes were also synthesized and characterized by 1H NMR spectroscopy.

Ring-opening polymerization is an essential form of chain-growth polymerization that facilitates precise control over the polymerization process. Our research delved into the realm of redox- switchable catalysis and its application in synthesizing polyesters, ethers, and carbonates through ring-opening polymerization. To broaden the range of available monomers, we also explored the ring-opening polymerization of aromatic N-carboxyanhydrides with six-membered rings, resulting in the creation of aromatic polyamides. Leveraging the potential of biodegradable polymers crafted from ring-opening polymerizations, we investigated how the stereocomplexation of block copolymers could enhance the shear viscosities of the polymer solutions in brine.

Rare-earths are a group of metals with fascinating physical properties and intriguing chemical reactivity. Organometallic rare-earth chemistry is of particular interest because of the increasing number of their applications in industry and consumer goods as well as the importance of understanding their physical and chemical properties. Despite the dominance of the trivalent oxidation state, recently, low-valent organometallic rare-earth compounds were characterized and showed interesting reactivity toward various molecules. The theme of this thesis is the reduction chemistry of rare-earth metal complexes. By utilizing an electronically and geometrically flexible ferrocene diamide ligand (NN^TBS = fc(NSi^tBuMe₂)₂, fc =1,1’-ferrocenediyl), unprecedented reactivity was discovered together with the synthesis and characterization of a series of rare-earth metal arene complexes. The fruitful reduction chemistry allowed: (1) the discovery of a new aromatic C-H and C-F bond activation mechanism for rare-earths; (2) the synthesis of the first scandium naphthalene complex and a reactivity study on P₄ activation by rare-earth arene complexes; (3) the isolation and characterization of a 6C, 10π-electron aromatic system stabilized by coordination to rare-earth metal ions. Recently, an improved method to access paramagnetic rare-earth starting materials for organometallic chemistry was developed in order to study the physical and chemical properties of paramagnetic rare-earth biphenyl complexes.

Developing methodologies to synthesize high-value products efficiently from simple substrates with control over the reactivity and selectivity is highly favored by the chemical industry. Employing assisted tandem catalysis, where serial reactions can be carried out in one pot, to achieve streamlined complex syntheses significantly reduces the number of steps and waste. Harnessing spatial and temporal control in catalysis enables approaches toward one-pot transformations and allows the integration of several catalytic processes. Ferrocene-based ligand-supported metal complexes represent a promising class of catalysts that can incorporate redox control over catalytic processes. We have developed a redox-controlled selective hydroamination reaction catalyzed by (thiolfan*)Zr(NEt2)2 (thiolfan*= 1, 1'-bis (2,4-di-tert-butyl-6-thiophenoxy)ferrocene). In situ switching of the catalyst’s state during the reaction enables selectivity toward different substrates (Chapter 2).Incorporating the greenhouse gas CO2 into N-carboxyanhydrides (NCAs) followed by subsequent NCA utilization illustrates the possibility of integrating two synthetic steps in one vessel to afford a valuable material with possible CO2 recycling. To demonstrate the immense potential of integrating multi-step transformations in one pot, we developed a set of sustainable conditions for NCA synthesis (Chapter 3). Moreover, several metal catalysts supported by ferrocene-based ligands were found to catalyze NCA polymerization in the presence of a co-catalyst. To establish an integrated system composed of two incompatible processes, we aimed to compartmentalize the active reagents for each step. The structure of the ferrocene-based pro-ligand was modified for surface anchoring. Our efforts toward immobilizing ferrocene-supported metal catalysts onto conductive surfaces pave the way of achieving spatiotemporal control over the processes of NCA synthesis and polymerization (Chapter 4). In addition to the redox-switchable characteristic, ferrocene-based compounds provide a unique platform to support lanthanides and engender distinctive optical properties to them. We synthesized and characterized a series of ytterbium complexes displaying an ultra-narrow absorption in the ultraviolet-visible (UV-Vis) region. The extraordinarily narrow linewidth observed for (thiolfan)YbCl(THF) (thiolfan = 1,1′-bis(2,4-di-tert-butyl-6-thiomethylenephenoxy)ferrocene) allows us to investigate its applications toward magnetic field and liquid cell quantum sensing (Chapter 5).