Metal–ligand bonds in [(X4R4)Fe(CO)3] (X = Si, Ge, Sn; R = SiH3, SiF3, F, Cl, Br, SiCl3, SiBr3, H, CH3, Si(CH3)3, Si(t-Bu)2Me) compounds

Abstract

This project deals with the study of the structure and the nature of the metal–ligand bonds in [(X4R4)Fe(CO)3] (X = Si, Ge, Sn; R = SiH3, SiF3, F, Cl, Br, SiCl3, SiBr3, H, CH3, Si(CH3)3, Si(t-Bu)2Me) compounds and also the effect of substituents on the planarity of X4R4 ring at M06/def2-SVP level of theory. Initially, the interaction energy between X4R4 and Fe(CO)3 fragments in [(X4R4)Fe(CO)3] compounds is calculated. The amount of charges of atoms, Wiberg bond indices, and donor-acceptor interactions for XFe bonds and also the amount of the charge transfer from X4R4 to Fe(CO)3 fragments in these compounds is also calculated through NBO analysis. Results indicate that in these compounds, the tendency to planarity is reduced from Si to Sn, and also no bulky substituents have the least impact on the planarity of X4R4 rings. Also, the AIM analysis was used to determine the bond critical points (BCPs) in the XFe bonds. Finally, the nature of X–Fe bonds are analyzed by the help of energy decomposition analysis (EDA) and results show that the main portion of ΔEint is attributed to ΔEorb (about 47%–61%).