The present invention is directed to compositions and methods for the recovery of olefins from a mixture. The compositions of the present invention comprise: (1) a transition metal ion; (2) a counter anion; (3) a ligand selected from the group consisting of a bidentate ligand and a tridentate ligand, wherein the ligand comprises at least two nitrogen atoms, and wherein each of the nitrogen atoms comprises a lone pair of electrons; and (4) a polar solvent with a boiling point of at least about 200.degree. C. The methods of the present invention comprise: (1) providing the aforementioned compositions; (2) bonding at least a portion of the olefins in a mixture to the transition metal ion in the composition to form a complex; (3) separating the complex from the mixture; and (4) recovering the olefins from the complex.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 The United States Government has rights in this invention pursuant to Contract No. DE-FG02-05ER84262 between the United States Department of Energy and Trans Ionics Corporation.