Two Uranyl Complexes with Pyromellitic Acid. A Heterometallic Complex with U=O-CuIIInteraction

Two uranyl complexes based on pyromellitic acid were hydrothermally synthesized, and their X-ray single-crystal diffraction structures were determined. Complex [UO2(Hbtec)]–(Himd)+·H2O (1) (H4btec = pyromellitic acid, imd = imidazole), is an ionic complex, which shows a typical (4, 4) topological structure in the space. A heterometallic complex, UO2Cu(btec)(phen) (2) (phen = 1,10-phenanthroline) results from the reaction of uranyl nitrate and copper(II) bromide with pyromellitic acid. The structure of complex 2 revealed that the chains of UO7 and CuO3N2 units were connected to each other through the carboxyl groups and U=O–Cu interactions to create a two-dimensional framework.