[en] The new dioxouranium (VI) Schiff base complexes [UO₂(sal-OAP)(H₂O)], [UO₂(sal-OAP)(py)], [UO₂(sal-OAP)(DMF)] and [UO₂(sal-OAP)(Et₃N)](sal-OAP orthoaminophenolsalicylideneiminato) have been prepared, and their i.r. spectra recorded and assigned on the basis of C_s symmetry. The bond stretching force constants of the uranyl bonds, F_U=O, were calculated as 661.7 Nm^-1, 676.1 Nm^-1, 674.5 Nm^-1 and 674.5 Nm^-1 for [UO₂(sal-OAP)(H₂O)], [UO₂(sal-OAP)(DMF)], [UO₂(sal-OAP)(py)] and [UO₂(sal-OAP)(Et₃N)], respectively. The corresponding values of the U = O bond lengths were calculated to be 1.745 A, 1.741 A, 1.742 A and 1.742 A. (author)