Uranyl complexes with the pyridine-2,6-dicarboxylato ligand: new dinuclear species with μ-η2,η2-peroxide, μ2-hydroxide or μ2-methoxide bridges

New dinuclear uranyl complexes are formed with pyridine-2,6-dicarboxylic acid in the presence of tertiary amines. The two uranyl ions, each of them bound to the nitrogen and two carboxylate groups of the ligand, are bridged by μ-η2,η2-peroxide, μ2-hydroxide or μ2-methoxide ions. The latter case is the first example of uranyl-bridging methoxide ions to be crystallographically characterized.