Coordinatively Unsaturated Amidotitanocene Cations with Inverted σ and π Bond Strengths: Controlled Release of Aminyl Radicals and Hydrogenation/Dehydrogenation Catalysis

Chemistry. 2021 Oct 20. doi: 10.1002/chem.202103487. Online ahead of print.ABSTRACTCationic amidotitanocene complexes [Cp2Ti(NPhAr)][B(C6F5)4] (Cp = η5-C5H5; Ar = phenyl (1a), p-tolyl (1b), p-anisyl (1c)) were isolated. The bonding situation was studied by Density Functional Theory using EDA-NOCV (Energy Decomposition Analysis with Natural Orbitals for Chemical Valence). The polar Ti-N bond in 1a-c features an unusual inversion of σ and π bond strengths responsible for the balance between stability and reactivity in these coordinatively unsaturated species. In solution, 1a-c undergo photolytic Ti-N cleavage to release Ti(III) species and aminyl radicals ⸱NPhAr. Reaction of 1b with H3BNHMe2 results in fast homolytic Ti-N cleavage to give [Cp2Ti(H3BNHMe2)][B(C6F5)4] (3). 1a-c are highly active precatalysts in olefin hydrogenation and silanes/amines crossdehydrogenative coupling, whilst 3 efficiently catalyzes amine-borane dehydrogenation. The mechanism of olefin hydrogenation was studied by DFT and the cooperative H2 activation key step was disclosed using the Activation Strain Model (ASM).PMID:34669988 | DOI:10.1002/chem.202103487

Source: Chemistry - October 20, 2021 Category: Chemistry Authors: Adrien Thomas Normand Quentin Bonnin Tereza Edlov á E Daiann Sosa Carrizo Paul Fleurat-Lessard H élène Cattey Philippe Richard Pierre Le Gendre St éphane Brandès Source Type: research