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

Abstract

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 (3)F(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.

Synthesis and Characterization of Water Stable Uranyl(V) Complexes

“…Notably, complex 2 yields two distinct excitation spectra at λ em =445 and 525, as well as three different emission spectra ( λ ex =304, 385 and 445). This differs from the excitation independent emission spectra previously reported for U IV chlorides or for the [U IV (DO3A)] + complex [37a, 40] …”

On the Aqueous Chemistry of the UIV–DOTA Complex

“…The set is noted as 1 m in Table and seemed to disappear completely only at pD>8.8. These two sets, 1 and 1 m , are expected to originate from the square‐antiprismatic/twisted‐square‐antiprismatic (SAP/TSAP) geometries of complex 1 , as suggested previously for the [U(DO3A)(dmso) 2 ]Br (DO3A=(4,7,10‐tris‐carboxymethyl‐1,4,7,10‐tetraazacyclododec‐1‐yl)acetic acid) complex and for other Ln III –DOTA complexes . According to the crystallographic analysis shown previously for [U IV (κ 8 ‐DOTA)(dmso)], and herein for complex 2 , the dominant species is expected to be that in the SAP geometry.…”

Investigating subtle 4f vs. 5f coordination differences using kinetically inert Eu(iii), Tb(iii), and Cm(iii) complexes of a coumarin-appended 1,4,7,10-tetraazacyclododecane-1,4,7-triacetate (DO3A) ligand

“…[41][42][43] Here, we investigate a series of kinetically inert complexes of Eu(III), Tb(III), and Cm(III) to decipher subtle coordination differences between the 4f and 5f elements, using a macrocyclic ligand appended with an antenna chromophore (L, Figure 1). In the actinide series, Cm is a paradigm for direct comparisons with Tb(III) and Eu(III) since (i) it has long-lived isotopes (e.g.…”