Cation–cation interaction in crystal structures of Np(V) and Pu(V) benzoate complexes with 2,2′-bipyridine, [NpO₂(C₁₀H₈N₂)(OOCC₆H₅)]₂ and [PuO₂(C₁₀H₈N₂)(OOCC₆H₅)]₂

Abstract

Single crystals of the Np(V) and Pu(V) benzoate complexes with 2,2′-bipyridine were prepared. According to X-ray diffraction analysis data, they are isostructural neutral dimers with the [AnO 2 (C 10 H 8 N 2 )(OOCC 6 H 5 )] 2 (An = Np or Pu) composition. In crystals of these compounds the AnO 2 + are linked to each other in pairs, acting simultaneously as ligands and coordinating centers. Due to the cation-cationic interaction the dimeric An 2 O 4 2+ cations are formed with the very short An…An distance equal to 3.4281(5) and 3.4088(14)Å for Np and Pu, respectively. The [NpO 2 (C 10 H 8 N 2 )(OOCC 6 H 5 )] 2 complex is a new representative of compounds containing a very rare system of cation–cation bonds in the structure. The cation–cation bonds and the Pu 2 O 4 2+ dimeric cations in the [PuO 2 (C 10 H 8 N 2 )(OOCC 6 H 5 )] 2 structure have been found for the first time.