Hosseinmardi Soosan, Scheurer Andreas, Heinemann Frank W, Marigo Nicola, Munz Dominik, Meyer Karsten
Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058, Erlangen, Germany.
Inorganic Chemistry, Coordination Chemistry, Saarland University, Campus C4.1, 66123, Saarbrücken, Germany.
Chemistry. 2023 Nov 16;29(64):e202302063. doi: 10.1002/chem.202302063. Epub 2023 Oct 6.
Dihydrogen evolution was observed in a two-step protonation reaction starting from a Ni precursor with a tripodal N-heterocyclic carbene (NHC) ligand. Upon the first protonation, a Ni monohydride complex was formed, which was isolated and fully characterized. Subsequent protonation yields H via a transient intermediate (INT) and an isolable Ni acetonitrile complex. The latter can be reduced to regenerate its Ni precursor. The mechanism of H formation was investigated by using a deuterated acid and scrutinized by H NMR spectroscopy and gas chromatography. Remarkably, the second protonation forms a rare nickel dihydrogen complex, which was detected and identified in solution and characterized by H NMR spectroscopy. DFT-based computational analyses were employed to propose a reaction profile and a molecular structure of the Ni-H complex. Thus, a dihydrogen-evolving, closed-synthetic cycle is reported with a rare Ni-H species as a key intermediate.
