Pyrrolyl-substituted polysilanes were synthesized in the present study. The
pyrrolyl rings directly attached to the Si conjugated main chains with Si-
N bonds. Poly(alkylpyrrolylsilane) and poly(phenylpyrrolylsilane) showed a
chromophore which is attributed to sigma-sigma* transition in the conjugate
d system associated with near-UV fluorescence. However, a strong photolumin
escence band was observed at 450-500 mn other than the near-UV photolumines
cence for the polysilanes. The luminescence is due to the energy relaxation
from sigma* to an inter-band level produced by sigma-pi mixing between mai
n chain sigma-conjugated system and pyrrolyl groups as suggested by theoret
ical calculations. Transient spectroscopy of the polysilanes was also carri
ed out showing a new chromophore at the vis-IR region (800 nm) other than n
ear-UV (300-400 nm) and IR (similar to 2000 nm) absorption bands typically
observed for alkyl- and phenyl-substituted polysilanes. It also supports th
e presence of the mid-gap level in the pyrrolyl-substituted polysilanes. (C
) 2000 Elsevier Science S.A. All rights reserved.