Synthesis, structure and optic properties of 2-methylimidazolium and 2-phenylimidazolium uranyl acetates

Two new salts based on heterocyclic organic cations and uranyl triacetate anion were obtained via reaction of zinc uranyl acetate with 2-substituted imidazoles in presence of an excess of acetic acid. Uranyl triacetate anion in [2-MeImH] + [UO 2 (CH 3 COO) 3 ] − and [2-PhImH] + [UO 2 (CH 3 COO) 3 ] − H 2 O has an expected bipyramidal structure with linear uranyl group and three acetate groups laying in equatorial plane. [2-MeImH] + [UO 2 (CH 3 COO) 3 ] − structure analysis reveals H-bonded 1D chains connected through N–H···O hydrogen bonds. 2-phenylimidazolium in [2-PhImH] + [UO 2 (CH 3 COO) 3 ] − H 2 O demonstrate planar geometry without any rotation of its rings, which was not registered before. H-bonds and π–π interactions of phenyl groups in this system lead to complicate 2D “sandwich” layer formation. The main features of IR- and luminescence spectrum of both compounds are also discussed.