Novel ligand materials and transition metal complexes thereof are disclosed which are useful as solvents and/or catalysts for various processes, including catalytic conversion processes for the conversion of hydrocarbons or carbon monoxide, such as the hydrocarbonylation of olefins, hydrogenation using H.sub.2 or CO and H.sub.2 O, dehydrogenation, hydrocarbon synthesis, alcohol synthesis, and water-gas disproportionation catalysis. Among the novel ligand materials disclosed are compositions containing phosphine and arsine coordinating groups along with, e.g., groups comprising fluorines, ethynyl or ethenyl groups, quaternary ammonium, arsonium and/or phosphonium groups. Ligands containing M--O--L linkages and complexes thereof are also disclosed wherein M is selected from, for example, Si or Ti and L is selected from P or As. Also, various ion-exchanged ligand compositions, photoreactive compositions and the uses of such compositions are also described.