Synthesis, structure and redox properties of a new ruthenium(n) complex containing the flexible tridentate ligand W,/V-bis(2-pyridylmethyl)ethylamine, c/s-/ac-Ru(bpea)22+, and its homologue attached covalently to a polypyrrole filmf

New ruthenium complexes bearing tridentate ligands of general formula cû-c-[RuIIL2][PF6]2 (L = N,N-bh(2pyridylmethyl)ethylamine (bpea) 1 or Ar-[3-bis(2-pyridyImethyl)aminopropyl]pyrrole (bpea-pyr) 2) have been prepared following two different synthetic routes. They have been characterised by elemental analyses, UV-Vis and 'H NMR spectroscopy. Furthermore, the crystal structure of complex 1 has been solved. The Ru is co-ordinated in a distorted octahedral fashion by six N atoms of two bpea ligands which occupy opposite faces of the octahedron. The aliphatic N atoms of the bpea ligands are co-ordinated in a cis fashion. 1-D together with 2-D NMR spectra show that in solution 1 has the same structure as in the solid state and that complex 2 has the same structural arrangement. The redox properties of 1 and 2 have been investigated by cyclic voltammetry and coulometry. In the anodic region, the pyrrole group of complex 2 polymerises forming a modified electrode containing Pt/poIy-2. This new material has been characterised by electrochemical techniques and displays a remarkable chemical and electrochemical stability. © The Royal Society of Chemistry 2000.