| Project/Area Number |
11640496
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | Gunma University |
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Principal Investigator |
TOBITA Seiji Gunma University, Department of Chemistry, Professor, 工学部, 教授 (30164007)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | aromatic amines / internal conversion / fluorescence / radiationless transitions / solvent effects / substituent effects / transient absorption / photoionization / アミノナフタレン / 無輻射過程 |
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| Research Abstract |
Effects of structural changes in the amino group on the relaxation processes of N,N-dimethyl-1- aminonaphthalenes and aniline derivatives were investigated by time-resolved fluorescence, transient absorption and time-resolved photothermal measurements. For N,N-dimethyl-1-aminonaphthalenes it was revealed that structural changes from trwisted to quasi-planar from in the excited state induce vibronic coupling between closely-lying S_1 and S_2 states, resulting in very fast internal conversion in nonpolar solvents. Such a fast nonradiative process was also found for aniline derivatives which have a twisted amino group in the ground state. This work showed that characteristic solvent effects on the relaxation processes of excited aromatic amines could be attributed to structural changes of the amino group in the excited state.
The structural change of the amino group from a pyramidal to quasi-planar upon electronic excitation results in intramolecular charge transfer from the nitrogen atom into the ring. As a result photoionization threshold is lowered and one-photon ionization upon 266 or 308nm photon excitation was found to become possible for aniline derivatives in water.
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