A comparison of the pentaammine(pyridyl)ruthenium(II) and 4-(dimethylamino)phenyl groups as electron donors for quadratic non-linear optics.

Hyper-Rayleigh scattering and Stark spectroscopic studies show that the complex salts [1-4]PF6 have larger static first hyperpolarizabilities beta 0 than [5-8]PF6, because the higher HOMO energy of a (RuII(NH3)5)2+ centre more than offsets the superior pi-orbital overlap in the purely organic chromophores.