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

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 Si 5 rings, with reduced puckering in the Li‐coordinated complexes. Occupied frontier orbitals are mainly Si 5 /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)Si 5 Tip 5 , 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 S 7 and S 8 states. These results relate coordination and medium effects to the spatial character and intensity of individual vertical excitations.