INORGANIC CHEMISTRY IV: ORGANOMETALLIC CHEMISTRY

Definition, nomenclature and classification of organometallic compounds on the basis of bond type, concept of hapticity of organic ligands, 18-electron rule, preparation, properties and structure of alkyls and aryls of Li, important structural features of methyl lithium (tetramer) and trialkyl aluminium (dimer), concept of multicentre bonding in these compounds, role of triethylaluminium in polymerisation of ethene (Ziegler – Natta catalyst), species present in ether solution of Grignard reagent and their structures, Schlenk equilibrium.

Zeise’s salt: preparation and structure, evidences of synergic effect.

Ferrocene: preparation and reactions (acetylation, alkylation, metallation, Mannichcondensation). Structure and aromaticity, comparison of aromaticity and reactivity with that of benzene.

EAN rule of mononuclear, polynuclear and substituted metal carbonyls of 3d series, general methods of preparation (direct combination, reductive carbonylation, thermal and photochemical decomposition) of mono and binuclear carbonyls of 3d series, structures of mononuclear and binuclear carbonyls of Cr, Mn, Fe, Co and Ni using VBT, π-acceptor behaviour of CO (MO diagram of CO to be discussed), synergic effect and use of IR data to explain extent of back bonding and its comparison with that of Zeise’s salt.

Principles and important reactions of transition metal organometallics: coordinative unsaturation, oxidative addition and insertion reactions.

Study of the following industrial processes and their mechanism.

Homogeneous catalysis: hydrogenation of alkenes (Wilkinson’s catalyst), hydroformylation of alkenes (co salts), Wacker process

Heterogenous catalysis: Fisher-Tropsch synthesis (synthetic gasoline), water-gas shift reaction (synthesis gas by metal carbonyl complexes).

Introduction to inorganic reaction mechanisms: Energy profile of reaction transition states, patterns of reactivity and classification of mechanisms, thermodynamic and kinetic stability of metal complexes, labile and inert complexes, factors affecting the stability of complexes, kinetics of octahedral substitution, ligand field effects and reaction rates, mechanism of substitution in octahedral complexes in Co(III) complexes (acid hydrolysis).

Trans- effect-definition, trans effect series, theories of trans effect and uses, substitution reactions in square planar complexes of Pt (II), mechanism (S_N2) of nucleophilic substitution in square planar complexes.