Coordination- and Medium-Regulated Excited-State Charge Transfer in Nonplanar Pentasilacyclopentadienide π Frameworks.

Abstract

Density functional theory and time-dependent density functional theory were used to examine coordination- and medium-dependent electronic properties of six pentasilacyclopentadienide systems. All optimized structures contain nonplanar Si5 rings, with reduced puckering in the Li-coordinated complexes. Occupied frontier orbitals are mainly Si5/aryl-centered, whereas low-lying unoccupied orbitals are sensitive to ligand coordination. The selected near-UV/visible excitations exhibit ring-centered, delocalized, and charge-transfer (CT) character. For Li(XylNC)Si5Tip5, natural transition orbital (NTO) analysis identifies related ring-to-coordinated-unit excitation patterns in selected gas-phase, benzene, and n-hexane states. THF exhibits different fragment participation, with appreciable CT contributions in the optically active S7 and S8 states. These results relate coordination and medium effects to the spatial character and intensity of individual vertical excitations.

Abstract as supplied by the indexing source. © the authors / publisher.