PROTON MAGNETIC RESONANCE SPECTRA OF SOME ACTINIDE BETA-DIKETONE COMPLEXES

The nmr spectra of several actinide β-diketone complexes have been obtained in chloroform solution. As opposed to the solid-state structure, the structure in solution of the thorium and uranium dibenzoylmethane complexes is an undistorted square antiprism. Using the ligand 1-phenyl-1,3-hexanedione, the isotropic shifts of the uranium complex were separated into a pseudocontact shift and a contact shift. The contact shift was related to spin delocalization via the orbitals indicating the interaction of the π orbitals with these β-diketone ligands. The spin delocalization is a small effect being only about one-fifth of that observed for the transition metal ions. © 1969, American Chemical Society. All rights reserved.