| Project/Area Number |
09304059
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Organic chemistry
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| Research Institution | MIE UNIVERSITY |
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Principal Investigator |
TOMIOKA Hideo Mie University, Faculty of Engineering, Professor, 工学部, 教授 (20024599)
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| Co-Investigator(Kenkyū-buntansha) |
HIRAI Katsuyuki Mie University, Faculty of Engineering, Assistant, 工学部, 助手 (80208793)
TAKAHASHI Yasutake Mie University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (70197185)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥28,400,000 (Direct Cost: ¥28,400,000)
Fiscal Year 1998: ¥8,600,000 (Direct Cost: ¥8,600,000)
Fiscal Year 1997: ¥19,800,000 (Direct Cost: ¥19,800,000)
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| Keywords | Kinetic Stabilization / Steric Protectors / Poly (diazo) Compounds / Polycarbenes / Lifetime Measurement / Electron Spin Resonance / SQUID / Photolysis / トリフルオロメチル基 / トリブチシル基 / ポリジアゾ化合物 / ポリカルベン / 磁気的測定 / ビシクロオクチル基 / ジアゾ化合物 |
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| Research Abstract |
This research was undertaken to stabilize and isolate a triplet carbene and to use it as a spin unit for stablehigh-spin organic molecules.
Steric protection is an ideal method of stabilizing the triplet carbene since a protecting group when introduced near carbene center not only blocks the carbene center from external reagents but also results in thermodynamic stabilization by increasing the central bond angle. However, clue to a voracious appetite of carbenes for electrons, this strategy encounters limitation when alkyl groups are employed as protecting group. In this light, it is crucial to develop a new protecting group which is sterically congesting but unreactive toward triplet carbenes. We found the oretically bulky yet poor H donating alkyl groups such as bicyclo[2.2.2]octyl and triptycyl groups and heteroatomsubstituents such as bromine and trifluoromethyl groups are effective kinetic protectors toward triplet carbenes and were able to generate triplet diphenylcarbene surviving more than one hour in solution at room temperature.
We also found serendiptously that the precursor diazomethanes for those stable triplet carbenes are also fairly stable and can be used as a building block for preparing poly(diazo) compounds. For instance, we were able to introduce ethynyl group at the para position of sterically congested diphenyldiazomethanes and to prepare tris- and hexakis(diazo)-methanes by subsequent coupling reaction using l, 3,6-tri(iodo)benzene. Polycarbenes generated from those poly(diazo) compounds were shown to have high spin states.
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