Calcium Hydride Cation [CaH](+) Stabilized by an NNNN-type Macrocyclic Ligand: A Selective Catalyst for Olefin Hydrogenation

Danny Schuhknecht (1) , Carolin Lhotzky (1) , Thomas P. Spaniol (1) , Laurent Maron (2) , Jun Okuda (1)

1 IAC RWTH - Institute of Inorganic Chemistry [Aachen]
2 LPCNO - Laboratoire de physique et chimie des nano-objets

Reaction of dibenzyl calcium complex [Ca(Me(4)TACD)(CH2Ph)(2)], containing the neutral NNNN-type macrocyclic ligand Me(4)TACD (Me(4)TACD=1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane), with triphenylsilane gave the cationic dinuclear calcium hydride [Ca2H2(Me(4)TACD)(2)](PhCHSiPh3)(2) which was characterized by NMR spectroscopy and single-crystal X-ray diffraction. The cation can be regarded as the ligand-stabilized dimeric form of hypothetical [CaH](+). Hydrogenolysis of benzyl calcium cation [Ca(Me(4)TACD)(CH2Ph)(thf)](+) gave dicationic calcium hydrides [Ca2H2(Me(4)TACD)(2)][BAr4](2) (Ar=C6H4-4-Bu-t; C6H3-3,5-Me-2) containing weakly coordinating anions. In THF, they catalyzed the isotope exchange of H-2 and D-2 to give HD and the hydrogenation of unactivated 1-alkenes.

Mots clés: hydrogenation; alkaline-earth metals; calcium hydride; isotope exchange

Domaines: Physique [physics]; Chimie

Danny Schuhknecht, Carolin Lhotzky, Thomas P. Spaniol, Laurent Maron, Jun Okuda. Calcium Hydride Cation [CaH](+) Stabilized by an NNNN-type Macrocyclic Ligand: A Selective Catalyst for Olefin Hydrogenation. Angewandte Chemie International Edition, 2017, 56 (40), pp.12367--12371. ⟨hal-01961163⟩