The thermodynamic and kinetic aspects of the rearrangement reactions of a series of metallabenzenes to cyclopentadienyl complexes have been investigated by DFT computational study in order to reveal how substituents on the metallacycle, ligands around the metal center, and metals affect the transformation. It was found that metals, substitutents and their locations on the metallacycle have a significant effect on the thermodynamics and kinetics of the rearrangement reactions. The effect of ligands is less important.

The electrophilic substitution reaction of the metallabenzyne Os(≡CC(R)=C(CH₃)C(R)=CH)Cl₂(PPh₃)₂ (R = SiMe₃) with NO₂BF₄ has been studied theoretically. Experimentally, the reaction produced an expected normal osmabenzyne complex and an unexpected paramagnetic carbe...[ Read more ]

The thermodynamic and kinetic aspects of the rearrangement reactions of a series of metallabenzenes to cyclopentadienyl complexes have been investigated by DFT computational study in order to reveal how substituents on the metallacycle, ligands around the metal center, and metals affect the transformation. It was found that metals, substitutents and their locations on the metallacycle have a significant effect on the thermodynamics and kinetics of the rearrangement reactions. The effect of ligands is less important.

The electrophilic substitution reaction of the metallabenzyne Os(≡CC(R)=C(CH₃)C(R)=CH)Cl₂(PPh₃)₂ (R = SiMe₃) with NO₂BF₄ has been studied theoretically. Experimentally, the reaction produced an expected normal osmabenzyne complex and an unexpected paramagnetic carbene complex. The theoretical study helps to clarify the mechanism of the reaction.

Some metallabenzynes could undergo migratory insertion reactions to give carbene complexes, while other structurally related metallabenzynes do not undergo the same kind reaction. A subtitle change in the substituents in the metallacycle can have a drastic effect on the transformation. A theoretical study suggests that the substituent effect is related to steric effect.


The aromatic property of rhenabenzynes and osmabenzynes have been evaluated by the aromatic stabilization energy (ASE) and nucleus-independent chemical-shift (NICS) values. The results suggest that these metallabenzynes have aromatic character.