High-Molecular-Weight Ruthenium(II) Coordination Polymers: Synthesis and Solution Properties

Abstract

A synthetic strategy is presented that allows the preparation of high-molecular-weight ruthenium(II) coordination polymers 1a,b of homogeneous molecular constitution. The key to this success was the development of an efficient procedure leading to highly pure “metal monomers” [Ru(R2bpy)Cl3]x (3a,b) with (b: R = C6H5) and without (a: R = H) lateral phenyl substituents. Their conversion with equimolar quantities of “ligand monomer” tetrapyrido[3,2-a:2‘,3‘-c:3‘‘,2‘‘-h:2‘‘‘,3‘‘‘-j]phenazine (2) gave excellently soluble ruthenium(II) coordination polymers 1a and 1b, respectively, the molecular constitution of which was proven with high-resolution 1H and 13C NMR spectroscopy. The degrees of polymerization were estimated to be Pn ≥ 30 because of the complete lack of end group absorptions in the NMR spectra. This estimate could be verified by small-angle X-ray scattering (SAXS) for the phenyl-substituted polymer 1b: according to these investigations, the molecular weight reaches Mw ≈ 47 000, and the radius of ...