Molecular and electronic structure analysis of [Fe(CO) 4 (SiX)] (X = O, S, Se and Te): a DFT study

DFT quantum calculations using B3LYP level of theory have been done for Fe(CO) 5 and for the axial and equatorial isomers of [Fe(CO) 4 (SiX)] (X = O, S, Se, Te). The total energy analysis shows the equatorial isomer to be more stable than the axial isomer. The data obtained from the NPA and EDA analysis reveals the bonding nature of these complexes. The WBI analysis reveals the bond index of M-SiX bond. The HOMO-LUMO energy gap of the complexes obtained from the FMO analysis lies in the 3.75 to 5.52 eV range, which is lesser than that found in Fe(CO) 5 . NBO analysis shows that the Fe atom's bond contribution (in Fe-Si bond) is lesser than that of Si atom. It shows a similar contribution to the carbonyl (in Fe-C bond) group, but the contribution from C atom is higher when compared to that of the Si atom. Graphical abstract The molecular and electronic structural analysis is done computationally using DFT on the axial and equatorial isomers of [Fe(CO) 4 (SiX)] (where, X = O, S, Se, Te) as well as the parent complex Fe(CO) 5 . The NPA, NBO, EDA, CDA, and WBI analysis is done on the 8 different [Fe(CO) 4 (SiX)] complexes where the Si-X bond exists in the axial and equatorial position and they are subsequently reported.