Macro‐Acyclic Pyrrophen Ligands for Hexadentate Coordination of Uranyl (UO₂²⁺)

Abstract Pyrrophen ligands are acyclic hexadentate ligands containing salen‐type N donors: two phenolic O donors, two pyrrolic N‐type donors, and two oxo‐carbonyl coordinating units. Uranyl complex derivatives of pyrrophen UO 2 L 1–2a‐c (L1=H); (L2=CH 3 ); (L=2‐pyridinemethanol (a), N‐(2‐pyridinylmethyl) (b), N‐benzyl (c), were synthesized and characterized by x‐ray diffraction (XRD), nuclear magnetic resonance (NMR), and UV‐vis. Each uranyl‐containing structure was found to crystalize in a hexagonal bipyramidal coordination environment. We observed solid‐state coordination deviations caused by the amide/ester substituent. The inductive effects and structural features were examined, and the effects on the bond lengths of the uranyl coordination and deviations in the ‐yl oxygen bond lengths and angles were studied.