First Example of Ugi’s Amine Application as a Platform for Chiral Coordination Polymers Construction: Synthesis and Properties

First example of phospinic acid containing Ugi's amine (HL) is presented. Utilization of this phospinic acid as a ligand in combination with 4,4’-bipyridine (bpy) facilitated the synthesis of first coordination polymer based on Ugi's amine with the composition Ni(bpy)2L2. The crystal structure of both, ligand and polymer, have been solved from single crystal X-ray diffraction data. The acid exists as zwitterion and crystalizes as mixture of two racemic forms. The coordination polymer consists of layers composed of Ni(bipy)2, terminated by L as monodentate ligands coordinated to the Ni trough the phosphinate group. Solid state сyclic voltammetry was used as analytical tool, which made it possible to estimate the iron to nickel ratio in the structure of coordination polymer. The cathodic shift of the oxidation potential of the ferrocene fragment in the polymer in comparison to free acid demonstrates a strong interaction of iron and nickel within the coordination polymer structure.