Polarizabilities of alkylsiloxanate and methoxysiloxanate anions

Ground state conformations and dipole polarizabilities of a series of substituted siloxanate anions [R1R2R3SiO]−, where the R groups represent methyl, methoxy or n-propyl substituents, have been obtained using a density functional (B-LYP) approach. The results show that propyl-substituted species are more polarizable (by ≈ 20–30%) than either trimethylsiloxanate or trimethoxysiloxanate anions. The different substituents confer increased polarizability with a heirarchy of α(methoxy)<α(methyl)<α(n-propyl).