Interaction of lanthanide shift reagents with co-ordination complexes; direct observation of nuclear magnetic resonance signals for free and complexed tris(pentane-2,4-dionato)cobalt(III) at ambient temperature, and X-ray crystal and molecular structure of the 1 : 1 adduct formed

Abstract

The changes in the ¹H n.m.r. spectrum of tris(pentane-2,4-dionato)cobalt(III) in CDCl₃ on incremental addition of tris(1,1,1,2,2,3,3,-heptafluoro-7,7-[²H₆]dimethyl[²H₃]octane-4,6-dionato)europium {Eu([²H₉]fod)₃} have been determined at 32°C; 1 : 1 adduct formation occurs, chemical exchange with respect to the n.m.r. time-scale being slow, and the 1 : 1 adduct has been shown by X-ray diffraction to have an unusual structure containing three bridging oxygen atoms.