Molecular Mechanics and Quantum Chemistry Study ofFerrocene and Cobaltocene

The eigen values, eigen vector and population analysis of ferrocene and cobaltoceneshow that the first ten molecular orbitals in ferrocene and first seven in cobaltocene havecontribution from 2pz orbitals of carbon of C5H5- and 3d orbitals of iron or cobalt. Theextent of involvement of metal orbitals in the two cases are different. In ferrocene themaximum involvement out of 4s and 4p orbital is in the order 4pz 4py 4s 4px and outof 3d orbitals the order of involvement is 3dyz 3dxz 3dz2 3dx2 - y2 3dxy. Theinvolvement of corresponding orbital in cobaltocene in respect of 4s and 4p orbitals is in theorder 4s 4pz 4px and in 3d orbitals the order is 3dyz 3dxy 3dxz 3dz2 3dx2 -y2. Thetotal involvement in respect of bonding between C5H5- and the metal orbitals as derived fromcoefficient values is 13.8 in ferrocene and 9.1 in cobaltocene. Comparison of eigen valuesindicate that ten most stable molecular orbitals have their energies in the range -0.4898 to-0.2314 eV in ferrocene and the seven most stable molecular orbitals in the range -0.4935to -0.3583 eV in cobaltocene. The energies of first molecular orbital in ferrocene is -1.1084eV and in cobaltocene -1.1027 eV. The population analysis shows that electrons from 2pzorbitals of carbon and 3d orbitals are provided in molecular orbital in both ferrocene andcobaltocene. The magnitude of contribution in the two cases differs significantly as thesum of the coefficient values of three 4p orbitals and five 3d orbitals in the ferrocene andcobaltocene are 13.8 and 9.1 respectively.