Oil-soluble metal thiolate-succinimide complexes

A process for preparing an oil-soluble metal thiolate-succinimide complex which comprises reacting (a) an alkyl or alkenyl mono- or bis-succinimide with (b) an oil-insoluble metal thiolate prepared by reacting

• (1) an acyloin of the formula:
• ##STR11## wherein R.sup.1 and R.sup.2 are the same or different and each is H, alkyl containing 1 to 30 carbon atoms, aryl containing 6 to 10 carbon atoms, alkaryl containing 7 to 30 carbon atoms, aralkyl containing 7 to 30 carbon atoms, or together R.sup.1 and R.sup.2 are alkylene and form a cyclic ring containing 4 to 6 carbon atoms which includes the carbon atoms to which they are attached, with phosphorus pentasulfide in an inert solvent at a temperature of from 25.degree. C. to 180.degree. C.;
• wherein the mole ratio of acyloin to phosphorus pentasulfide is at least 1 to 2;
• and
• (2) reacting the product from (1) with a reactive water-soluble, ionizable compound of a heavy metal in an aqueous solution whereby the final product (b) has a thiolato ligend of the formula:
• ##STR12## to metal ratio of from 0.5:1 to 1.5:1, and wherein the weight ratio of (a) to (b) is in the range of from 2:1 to 10:1.