On the CH⋯Cu agostic interaction: chiral copper(ii) compounds with ephedrine and pseudoephedrine derivatives

Abstract

The ephedrine derivative, (H₂ceph), yields [Cu(Hceph)₂], showing a CH⋯Cu(II) agostic interaction; while in the analogous compound [Cu(Hcpse)₂], with pseudoephedrine (H₂cpse), that interaction is absent, despite the fact that these two diasteromers differ only in the orientation of the methyl and phenyl groups: erythro in H₂ceph and threo in H₂cpse. The X-ray crystal structure of [Cu(Hceph)₂], indicates a Cu⋯HC length of 2.454 Å and the theoretical study reveals the formation of a Cu⋯HC bond since the associated electronic density shows both a bond critical point and a bond ring critical point.