Surface and Aggregation Behavior of Aqueous Solutions of Ru(II) Metallosurfactants: 1. Micellization of [Ru(bipy)2(bipy´)][Cl]2 Complexes

Small-angle neutron scattering has been used to determine the structure of micelles formed in aqueous solutions of [Ru(bipy)2(bipy´)][Cl]2 complexes where (bipy´) = 5,5´-dialkyl-2,2´-bipyridine. Surfactants with alkyl chains with carbon numbers of n = 12, 15, and 19 have been studied for which both alkyl chains on each molecule have the same chain length. For n = 12 the micelle shape is an oblate ellipsoid with the ratio of the minor-to-major axis radii being X ~ 0.5, for reasonably low concentrations (c </= 10cmc). For surfactants with n = 15 and n = 19, at concentrations c  </= 10cmc, the micelle shape is approximately spherical with X ~ 1.