Assembly of new Schiff base ligands derived from vitamin B6 and stabilization through complexation of N,N′-bis-(pyridoxylideneimine)-o-phenylene: Synthesis and X-ray structural features of pyridoxal/o-phenylenediamine adducts and of [UO2(H2pyr2phen)Cl]NO3

The new Schiff bases ligands 1 and 2 were obtained through reaction of vitamin B6 and o-phenylenediamine in methanol, and characterized structurally by X-ray diffractometry. The reaction of 1 with UO2(NO3)2 · 6H2O leads to the stabilization of N,N′-bis-(pyridoxylideneimine)-o-phenylene, giving [UO2(H2pyr2phen)Cl]NO3 (3) and [UO2(Hpyr2phen)Cl] (4). In the new chelate compounds 3 and 4 the uranium ions are the centers of distorted pentagonal bipyramides, characteristic for the coordination number 7. The positive charge of 3 is counter balanced by NO3− ions in the lattice. Deprotonation of an endo hydroxyl group of the ligand yields a neutral complex, in the case of 4. In both complexes a Cl− ion accomplishes the seventh coordination space around the uranium atom.

Graphical abstractThe reaction of a new Schiff base ligand – obtained through reaction of vitamin B6 and o-phenylenediamine – with UO2(NO3)2 · 6H2O leads to the stabilization of N,N′-bis-(pyridoxylideneimine)-o-phenylene, giving [UO2(H2pyr2phen)Cl]NO3 (3) and [UO2(Hpyr2phen)Cl] (4). In the new chelate compounds the uranium ions are the centers of distorted pentagonal bipyramides, characteristic for the coordination number 7.Figure optionsDownload full-size imageDownload as PowerPoint slide