<div><p>Nitrenes are reactive intermediates that are known to generate high interest organic molecules. Due to their inherent instability, nitrenes are often stabilized by introducing them to transition metal complexes. Many transition metal stabilized nitrenes (M=NR₂) have been reported and some of these complexes have been shown to control nitrene reactivity and selectivity. Transition metal nitrene reactivity can be categorized into two main groups: bond-insertion and group transfer reactions. In the reference to the former, chapter one of this dissertation highlights using unique dinuclear Nicatalysts to generate nitrenes from aromatic azides. These Ni₂ nitrenes are used towards selective C(sp²)−H bond amination in order to generate indole and carbazole derivatives. This work highlights the unique properties of the Ni₂ imide that enable a 1,2-addition pathway, which contrasts known bimetallic nitrene insertion reactions. A detailed mechanistic study, primarily using density functional theory (DFT) is the focus of this chapter.</p> <p>Chapter two of this dissertation focuses on nitrene group transfer. In particular, this chapter highlights the ability of the dinuclear Nicatalyst [<i>ⁱ</i>^-PrNDI]Ni₂(C₆H₆) to react with aromatic azides to perform N=N coupling. A large scope of functional groups are tolerated in high yield with short reaction times. Catalyst comparison studies, studies on relevant catalytic intermediates for N=N coupling and reaction kinetics are shown in this chapter. Lastly, chapter three showcases the expansion of the nitrene group transfer ability of [<i>ⁱ</i>^-PrNDI]Ni₂(C₆H₆) to generate high molecular weight azopolymers from aromatic diazides. These azopolymers are generated from monomers often used in organic semi-conducting materials. End group control and post polymer functionalization are highlighted in this chapter. Lastly, this work showcases a new polymer, polyazoisoindigo, as the first organic semiconducting material that reversibly transitions from a colored to colorless state upon reduction.</p><br></div>

<p> Metal-stabilized carbenes, most commonly formed through the decomposition of  diazoacetates, are extensively employed in organic synthesis. However, several classes of carbenes,  such as vinylidenes, are challenging to utilize in transition metal catalysis due to the instability of  the required diazo precursors. To overcome this challenge, most transition metal-catalyzed  vinylidene transfer and insertion methods rely on alkynes as vinylidene precursors. Only catalysts  that form stable M=C multiple bonds and weak M(π-C≡C) interactions can promote this alkyne  isomerization, and the resultant metal(vinylidene) species is often less reactive compared to free  vinylidenes. The discovery of 1,1-dihaloalkenes as precursors to transition metal vinylidene  complexes has significantly expanded the scope of vinylidene transfer and insertion reactions.  Dinuclear catalysts were found to promote the reductive cyclization of 1,1-dichloroalkenes  containing pendant alkenes to form methylenecycloalkenes, and mechanistic studies are consistent  with the formation of a Ni2(vinylidene) species. Furthermore, these catalysts promote reductive  three-component cycloaddition reactions with 1,1-dichloroalkenes and aldehydes to generate  methylenedioxolanes, which upon treatment with aqueous acid provides access in one step to new,  unsymmetrical aliphathic α-hydroxy ketones that would be difficult to access with existing  methods. Under dilute conditions, an enone byproduct is formed and a DFT model is presented  that accounts for concentration-based reaction selectivity.</p>