Search

The bulky β-diketiminate ligand frameworks [BDI DCHP ] - and [BDI Dipp/Ar ] - (BDI=[HC{C(Me) 2 N-Dipp/Ar} 2 ] - (Dipp=2,6-diisopropylphenyl (Dipp); Ar=2,6-dicyclohexylphyenyl (DCHP) or 2,4,6-tricyclohexylphyenyl (TCHP)) have been developed for the kinetic stabilisation of the first europium (II) hydride complexes, [(BDI DCHP )Eu(μ-H)] 2 , [(BDI Dipp/DCHP )Eu(μ-H)] 2 and [(BDI Dipp/TCHP )Eu(μ-H)] 2 , respectively. These complexes represent the first step beyond the current lanthanide(II) hydrides that are all based on ytterbium. Tuning the steric profile of β-diketiminate ligands from a symmetrical to unsymmetrical disposition, enhanced solubility and stability in the solution-state. This provides the first opportunity to study the structure and bonding of these novel Eu(II) hydride complexes crystallographically, spectroscopically and computationally, with their preliminary reactivity investigated., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

A dimeric β-diketiminato ytterbium(II) hydride affects both the two-electron aromatization of 1,3,5,7-cyclooctatetraene (COT) and the more challenging two-electron reduction of polyaromatic hydrocarbons, including naphthalene (E 0 =-2.60 V). Confirmed by Density Functional Theory calculations, these reactions proceed via consecutive polarized Yb-H/C=C insertion and deprotonation steps to provide the respective ytterbium (II) inverse sandwich complexes and hydrogen gas. These observations highlight the ability of a simple ytterbium(II) hydride to act as a powerful two-electron reductant at room temperature without the necessity of an external electron to initiate the reaction and avoiding radicaloid intermediates., (© 2021 Wiley-VCH GmbH.)