• 대한환경공학회지
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• 제35권2호
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• pp.124-130
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• 2013

모든 브롬화난연제 중 가장 많이 사용되고 있는 것은 TBBPA이다(상용화되고 있는 브롬화난연제물질 중 50%를 차지). TBBPA는 환경 중에서 유해하기 때문에 환경 중에서의 그들의 분해반응기전에 대한 연구가 흥미롭다. 본 연구에서는 UV-A (${\lambda}=352nm$) 조사에 의한 TBBPA의 광분해반응속도가 조사세기 의존적으로 증가하였다. 또한 TBBPA의 광분해반응에 의해서 2,6-dibromo-p-benzosemiquinone radical ($a_{2H}=2.36G$, g = 2.0056)이 생성되고 그 생성반응에 singlet oxygen ($^1O_2$)이 주요 반응 인자로서 영향을 미치는 것으로 나타났다. 한편, HA와 TBBPA의 혼합용액을 광조사하면 semiquinone radical의 전형적인 ESR 스펙트럼이 생성되었다. 그리고 HA는 TBBPA의 광분해반응속도를 농도의존적으로 감소시키는 것으로 나타났다. 또한 라디칼 생성과 광분해반응속도는 singlet oxygen ($^1O_2$) 소거제인 sodium azide를 주입하면 감소되었다. 이러한 결과로부터, UV-A 조사에 의한 HA와 $^1O_2$의 반응속도는 TBBPA와 $^1O_2$의 것보다 더 빠르다는 것을 제시한다.

• Bulletin of the Korean Chemical Society
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• 제19권3호
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• pp.367-369
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• 1998

• Bulletin of the Korean Chemical Society
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• 제7권6호
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• pp.478-479
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• 1986

• Bulletin of the Korean Chemical Society
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• 제5권6호
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• pp.265-266
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• 1984

• Journal of Photoscience
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• 제9권2호
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• pp.527-529
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• 2002

Photodynamic therapy (PDT) is a medical treatment using laser and photosensitizing drug taken up to destroy cancer cells. Singlet oxygen ($^1$0$_2$) generation is strongly related to this treatment. We have built a direct detection system monitoring feeble luminescence, in the near IR region, from $^1$0$_2$, We have comparatively studied the photophysical and photochemical properties in solution of a newly developed drug ATX-S10 and Photofrin already investigated clinically. We demonstrdted that ATX-S10 was capable of efficiently yielding $^1$0$_2$, which may lead to highly efficient PDT treatment. Successive laser excitation photobleached ATX -S10 readily in a dose-dependent manner. This result shows that ATX -S10 is useful in setting up suitable medical treatment conditions to minimize side effects.

• 한국환경과학회지
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• 제17권6호
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• pp.671-677
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• 2008

We studied to determine quantitatively the radical species generated from humic acid (HA) solutions by irradiation(>400 mn). The formation of radical species from HA solutions was investigated with ESR spectroscopy. We gave ESR spectrum with g-value 2.0048 and line width 0.559mT, coincided with those of the semiquinone radical. 0.1 mg/L HA solution generated the radicals of $1.2{\times}10^{-6}M$, increased with increasing HA concentration. Also, pH and ionic strength effect of the amount of the semiquinone radical generate from HA solution. In this study, we have found that the singlet oxygen affects the semiquinone radicals generation in HA solution.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.271-276
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• 2002

The energy relaxation dynamics of the lowest excited singlet and triplet states of the Zn(II)porphyrin monomer and its directly linked arrays were comparatively investigated with increasing the number of porphyrin moieties. While the fluorescence decay rates and quantum yields of the porphyrin arrays increased with the increase of porphyrin units, their triplet-triplet (T-T) absorption spectra and decay times remained almost the same. The difference in the trends of energy relaxation dynamics between the excited singlet and triplet states has been discussed in view of the electronic orbital configurations.

• Journal of Photoscience
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• 제6권2호
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• pp.57-60
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• 1999

The reaction of [1.1.1]propellane with singlet methylene afforded 1,3-dimethylenecyclobutane and [l.1.1.1]paddlane (3). Various minor products were also produced. The reaction of [1.1.1]propellane with triplet methylene afforded 1,3-dimethylenecyclobutane (2) and various minor products. But even trace of [1.1.1.1]paddlane was not detected. The mechanism for the addition of singlet methylene involved [1.1.1.1]paddlane intermediate The addition of triplet methylene led to diradical intermediate. In order to reveal the reaction pathway for generation of various ruiner products, various studies were carried out under the same condition.

• Bulletin of the Korean Chemical Society
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• 제25권8호
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• pp.1231-1237
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• 2004

Rate constants for photolytic reactions of p-substituted 2-diazopropiophenones were determined in acetonitrile. The reactions show a comparatively low value of activation energy and activation enthalpy to alkylcarbenes or other arylcarbenes. The transition state corresponds to the step of a new carbonyl bond formation. The high negative ρ -values are shown in Hammett plots. The kinetics results and EPR spectrum are in accord with a phenomenon that occurs in interconversion between singlet and triplet carbenes.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.916-920
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• 2003

Photoreactions of N-(2,4-dibromonaphthyl)arenecarboxamides in basic medium result in the intramolecular substituted products, 2-aryl-8-bromonaphthoxazoles in moderate yields and further photoreactions of the products afford the reduced products, 2-arylnaphthoxazoles. These reactions are straightforward for syntheses of naphthoxazole derivatives. Since the intramolecular photosubstitution of the bromoarenecarboxamide by the oxygen of its amide group is more effective than the photoreduction of the substituted product, 2-aryl-8- bromonaphthoxazole in basic medium, the intramolecular substituted product, 2-aryl-8-bromonaphthoxazole can be isolated. A charge-transfered excited singlet state of an imidol form of the 2-bromoarenecarboxamide is involved in the photosubstitution, whereas an excited triplet state of the 2-aryl-8-bromonaphthoxzole is closely involved in the photoreduction.