Liquid polynuclear hydrocarbyl ferrocenes

Compositions of matter consisting essentially of mixtures of polynuclear hydrocarbyl substituted ferrocene compounds, each ferrocene nucleus being substituted with at least one hydrocarbyl group, the total number of carbon atoms in the hydrocarbyl substituents of each substituted ferrocene nucleus being in the range of from 1-6, said compositions being noncrystalline, noncrystallizable liquids having an average molecular weight no greater than about 950, said compositions being miscible in all proportions in carboxyterminated polybutadiene at ambient conditions and being combustion catalysts for composite solid propellants. These compositions can be produced by free radical coupling of alkylferrocenes or by the condensation, at low temperature and in the presence of an inert diluent, of lower hydrocarbyl substituted ferrocene derivatives, said hydrocarbyl substituents having m carbon atoms, with aliphatic aldehydes containing n carbon atoms wherein m is an integer from 1-6, n is an integer from 1-12 and value of the relationship 2m +n is from 3-14. Dimeric and trimeric species are the most desirable.