Hydrogen-1 nuclear magnetic resonance study of uranyl complexes of di-2-pyridyl sulphide and di-2-pyridyl ketone

Hydrogen-1 n.m.r. spectra of uranyl complexes of the ligands (L) di-2-pyridyl sulphide (dps) and di-2-pyridyl ketone (dpk), [UO2L2]X2(X = Cl, ClO4, NO3, or NCS), have been run at 250 MHz in the pulsed Fourier-transform mode, and the observed induced shifts for the pyridine-ring protons have been analysed, by means of a computer-assisted method, in terms of the pseudo-contact equation and of the molecular conformation. In general, for protons in meta positions with respect to the heteroatom, the shifts observed are essentially dipolar in origin. The pseudo-contact equation in combination with the computer method can be employed to determine the molecular conformation of uranyl complexes in the solution state.