Some highlights from the development and use of bulky monodentate ligands

The development of bulky monodentate alkoxide, chalcogenolate (ER, E = S, Se or Te), amide, pnictide (ER2 = N, P, As), alkyl, aryl and silyl ligands is briefly surveyed. These ligands have played a key role in the advancement of the modern organometallic and inorganic chemistry of all the major blocks (s, p, d, and f) of the periodic table. Most importantly, they have permitted numerous new classes of compounds to be isolated and studied. The investigation of steric effects induced by these ligands has led to, inter alia, transition metal alkylidene and alkylidyne complexes, room temperature cleavage of dinitrogen, and a wide range of transition metal and lanthanide complexes with two or three coordination. In addition, their use has sparked a revolution in main group chemistry which has led to the isolation of stable species with bonds and/or oxidation states hitherto unknown in stable compounds.