Gel permeation experiments were employed to ascertain the approximate molecular masses of the polymer complexes. With Sephadex G-75 (rated MM 1000-50,000) as the stationary phase, solutions of the polymer complexes, appropriate model compounds, and a similar osmium polymer4.1, Os(bpy)2(polyvinylpyridine)Cl2 of known MM> 105 were eluted individually with aqueous methanol solutions acidified slightly with HCl. The polymers eluted simultaneously with the solvent front, while the relatively low molar mass model compounds were retained at the head of the column. From this it was concluded that the polymer complexes were true polymers, having MM greater than 5 ×104. This is sufficiently high that the electrochemical and spectroscopic properties of these systems may be considered to be reflective of a material of effectively infinite chain length; the electronic properties of conjugated systems are known to converge to approximately constant values by ca. twenty repeat units [123].