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Browsing by Author "Hadlington, Terrance J."

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    Accessing the main-group metal formyl scaffold through CO-activation in beryllium hydride complexes
    (Nature Portfolio, 2022) Hadlington, Terrance J.; Szilvasi, Tibor; Technical University of Munich; University of Alabama Tuscaloosa
    Carbon monoxide (CO) is an indispensable C1 building block. For decades this abundant gas has been employed in hydroformylation and Pausen-Khand catalysis, amongst many related chemistries, where a single, non-coupled CO fragment is delivered to an organic molecule. Despite this, organometallic species which react with CO to yield C1 products remain rare, and are elusive for main group metal complexes. Here, we describe a range of amido-beryllium hydride complexes, and demonstrate their reactivity towards CO, in its mono-insertion into the Be-H bonds of these species. The small radius of the Be2+ ion in conjunction with the non-innocent pendant phosphine moiety of the developed ligands leads to a unique beryllium formyl complex with an ylidic P-C-CO fragment, whereby the carbon centre, remarkably, datively binds Be. This, alongside reactivity toward carbon dioxide, sheds light on the insertion chemistry of the Be-H bond, complimenting the long-known chemistry of the heavier Alkaline Earth hydrides. Stoichiometric carbon monoxide insertion processes leading to metal-formyl complexes are scarce, even for transition metals. Here, light is shed on the underexplored chemistry of beryllium hydrides leading to a stable example of a main group metal-formyl complex.
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    Reversible metathesis of ammonia in an acyclic germylene-Ni-0 complex
    (Royal Society of Chemistry, 2021) Keil, Philip M.; Szilvasi, Tibor; Hadlington, Terrance J.; Technical University of Munich; University of Alabama Tuscaloosa
    Carbenes, a class of low-valent group 14 ligand, have shifted the paradigm in our understanding of the effects of supporting ligands in transition-metal reactivity and catalysis. We now seek to move towards utilizing the heavier group 14 elements in effective ligand systems, which can potentially surpass carbon in their ability to operate via 'non-innocent' bond activation processes. Herein we describe our initial results towards the development of scalable acyclic chelating germylene ligands (viz.1a/b), and their utilization in the stabilization of Ni-0 complexes (viz.4a/b), which can readily and reversibly undergo metathesis with ammonia with no net change of oxidation state at the Ge-II and Ni-0 centres, through ammonia bonding at the germylene ligand as opposed to the Ni-0 centre. The DFT-derived metathesis mechanism, which surprisingly demonstrates the need for three molecules of ammonia to achieve N-H bond activation, supports reversible ammonia binding at Ge-II, as well as the observed reversibility in the overall reaction.