The first structural and spectroscopic study of a paramagnetic 5f DO3A complex

A 5f 2 uranium(iv) complex of the macrocycle DO3A (DO3A = [4,7,10-tris-carboxymethyl-,1,4,7,10-tetraaza-cyclododec-1-yl]-acetic acid) has been prepared and characterised in the solid state and in solution. The DO3A scaffold containing no strongly absorbing chromophores enables the facile detection of relatively long-lived (8-13 ns) UV-visible emission that possesses significant charge transfer character tentatively assigned to deactivation of the excited 3F 2 5f 1 6d 1 electronic configuration. This study demonstrates, for the first time, that luminescence of simple U(iv) chelates is detectable in the absence of an antenna, potentially serving as a diagnostic tract for environmental U(iv) species. © 2012 The Royal Society of Chemistry.