Internal dynamics in organometallic molecules: Rotational spectrum of (CH₃)₃GeCl

The microwave spectra of (CH₃)₃⁷⁴Ge³⁵Cl and its isotopologues (CH₃)₃⁷²Ge³⁵Cl and (CH₃)₃⁷⁴Ge³⁷Cl have been studied in the frequency range from 3–24 GHz revealing the complex internal dynamics of this organometallic molecule with three internal rotors. The assignment of the complex spectrum has been facilitated by permutation–inversion theory and ab initio calculations. The V₃ barrier to internal rotation is determined to be 372.359(47) cm^–1. Furthermore, an analysis of the chlorine quadrupole coupling yields the description of the Ge–Cl bonding character which is estimated to be dominated by covalent contributions (46.5%) together with 37.6% ionic and 15.9% π-bonding character. From isotopic substitution the Ge–Cl bond distance could be determined as 2.15198(97)Å