Excited-state behavior of phenylethynyldisilanes: an intramolecular charge-transfer emission
Photochemical and photophysical properties of phenylethynyldisilanes in MP (methylcyclohexane/isopentane, 3:1 v/v) have been studied by means of picosecond and nanosecond spectroscopy along with steady-state experiments. Intramolecular charge transfer in the excited singlet state of phenylethynyldisilanes occurs very rapidly (<10 ps) at both 77 and 294 K. This finding shows that internal rotation (or twisting) or solvation is not necessary for the intramolecular CT formation of phenylethynyldisilanes. The mechanism on the intramolecular CT from the /sup 1/(..pi..,..pi..*) state to the /sup 1/(2p..pi..,3d..pi..) CT state of the compounds is quite different from that of the usual TICT (twisted intramolecular charge transfer). Two decay components (fast and slow) of the /sup 1/CT state are observed, which are ascribed to the intersystem crossing rates from /sup 1/CT to /sup 3/(..pi..,..pi..*), depending upon the molecular conformations of the /sup 1/CT state of phenylethynyldisilanes. The photochemical reaction to produce silacyclopropenes takes place effectively via the /sup 1/CT state at room temperature, but not in MP glass at 77 K.
- Research Organization:
- Gunma Univ., Japan
- OSTI ID:
- 6800124
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 91:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
SILANES
2-METHYLBUTANE
ABSORPTION SPECTRA
CONFORMATIONAL CHANGES
CYCLOHEXANE
EMISSION SPECTRA
EXCITED STATES
EXPERIMENTAL DATA
PHOTOCHEMISTRY
STEADY-STATE CONDITIONS
TEMPERATURE DEPENDENCE
ALKANES
CHEMICAL REACTIONS
CHEMISTRY
CYCLOALKANES
DATA
ENERGY LEVELS
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC SILICON COMPOUNDS
SILICON COMPOUNDS
SPECTRA
400500* - Photochemistry