CHIRALITY IN COORDINATION-COMPOUNDS

Alfred Werner conjectured as early as 1899 that octahedrally coordinated metal complexes should occur in nonidentical mirror image isomers. For such objects, Lord Kelvin, in 1893, had coined the adjective ''chiral'', a term never used by Werner. It can be proved by examination of the original sample of [Co(NO2)(2)(en)(2)]Br, prepared by Edith Humphrey, a Ph.D. student of Werner's, that crystals of optically pure samples were obtained in Werner's laboratory as early as 1899 or 1900. However, Werner did not publish the first successful resolution of an octahedral metal complex until 1911. Presently, interest in chirality in coordination compounds is booming, mainly because of the importance of coordination compounds in enantioselective homogeneous catalysis. Other interesting applications are enantioselective interactions of chiral coordination species with biomolecules, and the stereoselective synthesis of multicenter systems.