The first molecularly defined catalyst was the Co carbonyl hydroformylation catalyst discovered by Roelen in 1938.Its mechanism. defined in physical organic terms, was unraveled in the 1960 s by Heck and Breslow, and it was later developed commercially by Shell.
Earlier, mercury sulfate had been industrially applied for the conversion of acetylene to acetaldehyde. Later , in the 1950s, the Wacker process of selective oxidation of ethylene catalyzed
The Ziegler-Natta invention of an ethylene and propylene polymerization catalyst in the 1950s, based on 〖TiCl〗_3, signaled the beginning of well-defined (immobilized) coordination complexes serving as catalytically active species, in parallel with the development of metal-organic chemistry.
This development was crowned by Wilkinson's discovery of homogeneous hydrogenation in 1965. The catalyst , RhCl, consists of a single metallic center stabilized by triarylphosphines. The unique feature of such organometallic complexes is that can manipulated molecularly by variation of the ligands. with their invention the field of molecular catalysis has been expended from the organic chemist is realm into metal-based catalysis. Catalyst design through development of physical approaches, ligand synthesis, and computational modeling techniques has become one of the outstanding features of this branch of catalysis.
These developments have provided the basis of several large-scale homogeneous bulk industrial processes. Examples are the Rh-based carbonylation of methanol and hydroformylation processes. More recently we see the development of metathesis applied, for instance, in the ring-opening polymerization process of Huels, and enantiomeric catalysis due to invention of highly enantiomeric ligand systems, as for the production L-Dopa by Monsanto.