aromaticity in benzenoid and non benzenoid compounds pdf

The peripheral bonds have similar lengths and it undergoes Friedel-Crafts-like substitutions The stability gain from aromaticity is estimated to be half that of naphthalene. Atul Prasad Sikdar Associate Professor Department of Chemistry Mangaldai College : AssamĢ Ferrocene organometallic compound with the formula Fe(C5H5)2Ĥ Ferrocene Synthesis : a) 2 C5H5MgBr + FeCl2 → Fe(C5H5)2 + MgCl2 + MgBr2 b) Fe + 2 C5H6(g) → Fe(C5H5)2 + H2(g) c) Fe(CO)5 + 2 C5H6(g) → Fe(C5H5)2 + 5 CO(g) + H2(g) d) 2 NaC5H5 + FeCl2 → Fe(C5H5)2 + 2 NaCl e) FeCl2.4H2O + 2 C5H6 + 2 KOH → Fe(C5H5)2 + 2 KCl + 6 H2O f) FeCl2 + Mn(C5H5)2 → MnCl2 + Fe(C5H5)2ĥ Ferrocene Reaction : a) Electrophilic substitutionĦ Ferrocene b) Lithiation : Ferrocene reacts readily with butyl lithium to give 1,1'-dilithioferrocene, which in turn is a versatile nucleophileħ Azulene Azulene is an organic compound and an isomer of naphthaleneĪzulene is usually viewed as resulting from fusion of cyclopentadiene and cycloheptatriene ringsĨ Azulene It exhibits aromatic properties The results also suggest that in compounds 1–3, the hydrogen elimination are controlled by LP(e) → σ* resonance energies.Presentation on theme: 'Aromaticity of Benzenoid and Non-benzenoid compounds'- Presentation transcript:ġ Aromaticity of Benzenoid and Non-benzenoid compounds Based on the optimized ground state geometries using the MPW1PW91/6-31++G** method, the natural bond orbital analysis (NBO) of donor–acceptor (bonding-antibonding) interactions revealed that by the increase of electronegativity of atom $ $ resonance energies and also, the HOMO-LUMO energy-gaps in the ground state structures increase. The nucleus independent chemical shift (NICS) values of all reactants, TSs and products indicate that all studied structures are aromatic and the studied reactions are controlled kinetically and thermodynamically by the change of the aromaticity.

Our results show that the MPW1PW91/6-31++G** method is in good agreement with the available experimental values. A theoretical study of the thermal decomposition kinetics of 2,5-dihydrofuran (1), 2,5-dihydrothiophene (2), and 3-pyrroline (3) has been carried out at the B3LYP/6-31++G**, B3PW91/6-31++G** and MPW1PW91/6-31++G** levels of theory.

Aromaticity in benzenoid and non benzenoid compounds pdf