Cobalt and nickel Salts of the highly branched trichain anionic surfactant sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutune-2-sulfona te (TCl4) are shown to be soluble in dense CO2, at concentrations up to 6 wt % at 500 bar pressure. This is a remarkably high solubility for such hydrocarbon transition metal surfactants in CO2. High-pressure small-angle neutron scattering (HP-SANS) has been used to study the surfactant aggregates in a normal organic solvent, cyclohexane, dense CO2, and also mixtures of these two pure solvents. The results show that transition metal TCl4 derivatives are viable compounds for incorporating reactive and functional metal ions into CO2.