메탄올수용액에서 암모니아의 광분해반응

박형련,오추하,성아영,김희정,오종훈,Park, Hyoung Ryun,Oh, Chu Ha,Sung, A Young,Kim, Hee Jeong,Oh, Jong Hoon 대한화학회 1997 대한화학회지 Vol.41 No.5

산소가 제거된 메탄올수용액에서 암모니아의 광화학반응을 25$^{\circ}C$에서 184.9 nm의 자외선을 이용하여 연구하였다. 메탄올과 암모니아의 몰분율이 각각 0.10, $5{\times}10^{-4}$인 수용액의 빛 조사에서 아미노화반응이 진행되어 메톡시아민, 핵사민, 1,1-디메칠히드라진, 디메칠아민, 포름아미드 그리고 소량의 에칠렌디아민 등이 생성되었다. 또한 이러한 생성물 이외에 포름알데히드, 에칠렌글리콜 및 글리옥살 등의 카르보닐화합물들과 히드라진도 함께 생성되었다. 반응의 결과 얻어진 각 생성물들에 대한 초기 양자수득율을 결정하였으며, 이들 값으로부터 메탄올과 암모니아가 혼합된 수용액의 광반응에 대한 가능한 반응메카니즘을 제시하였다. The photochemical reaction of ammonia in deoxygenated aqueous methanol has been investigated at 25$^{\circ}C$ using 184.9 nm UV light. Amination was carried out by irradiating the solution of reaction mixture, and the formation of methoxyamine, hexamine, 1,1-dimethylhydrazine, dimethylamine, formamide, and a small amount of ethylenediamine was observed. In addition to these, carbonyl compounds such as formaldehyde, ethyleneglycol, glyoxal, and hydrazine were also produced. The initial quantum yields of the products were determined and probable mechanisms for the photochemical reaction were presented on the basis of product analysis.

Spectroscopic Properties of Quercetin-3-O-rhamnoside and Quercetin-3-O-rutinoside in Aerosol-OT Reverse Micelles

박형련,Hai-Bo Liu,신성철,박종근,박기민 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.3

The anomalous spectroscopic properties of quercetin-3-O-rhamnoside (QCRM) and quercetin-3-O-rutinoside (QCRT) in AOT reverse micelle were studied. The excited state intramolecular proton transfer (ESIPT) occurs through the strong hydrogen bond between the –OH at position 5 and the carbonyl oxygen. Because the ESIPT can only happens in the S_1 state and the Franck-Condon factor involved in the S_2 → S-1 internal conversion is small, the S_2 → S_o emission alone appears. Because the molecular planarity is improved at the interior of the micelle, the excited state intramolecular charge transfer in the S1 state is extended, and the excited state is more tolerable for any quenching effects in the micelle. Therefore, an S_1 → S_o emission was newly discovered under this micelle microenvironment. For the S_2 → S_o emission, the quantum yields increase but the quantum yield of the S_1 → S_o emission approximately decreases as the water concentration in the micelle increases.

Spectroscopic Properties of the Quercetin–Divalent Metal Complexes in Hydro-Organic Mixed Solvent

박형련,김봉곤,김수진,윤진아,박기민 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.8

The formation and spectroscopic properties of quercetin (QCT)?divalent metal complexes were studied using Cu2+, Ni2+, Co2+, Mn2+, Zn2+, Mg2+, and Ca2+ in a hydro-organic mixed solvent. The change of UV/visible absorption spectra of QCT due to addition of a metal showed the complex formation. The intensity of fluorescence spectra increased gradually with titration of the metal. The experimental data and theoretical calculation suggest that Cu2+, Ni2+, Co2+, and Mn2+ coordinate the site between C(3)?OH and C(4)?O but Zn2+ prefers to bind to the site between C(5)?OH and C(4)?O. QCT?Cu2+, QCT?Ni2+, QCT?Co2+, and QCT?Mn2+ complexes exhibit S2???S0 fluorescence only as S1???S0 emission is absent due to the excited-state intramolecular proton transfer (ESIPT) at the S1 state. As this ESIPT cannot occur at the QCT?Zn2+ due to the chelation of Zn2+ at a different site, QCT?Zn2+ can produce characteristic S2???S0 and S1???S0 dual fluorescence.

Spectroscopic Properties of Apigenin in Various Bulk Solutions and Aerosol-OT Reverse Micelles

박형련,서정자,박철호,Duan Yu,박기민 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.9

The fluorescence and ultraviolet (UV)/visible absorption spectra of apigenin (API) were measured and examined in bulk solutions and aerosol-OT (AOT) reverse micelles. The Stokes’ shift in micelles is very small due to the small dipole moment change upon excitation. Since the intermolecular interaction between API and H2O in micelles is weak, the fluorescence parameters are relatively insensitive to the change in water concentration compared with those in bulk solutions. Since the B ring can rotate freely, the dihedral angle between the A, C, and B rings can be changed easily by the influence of the solvent. The potential energy curves of the electronic states show a very shallow or no minimum. Although the change in electronic energy by intermolecular interaction will be very small, the point where emission occurs on the energy curve can be altered very sensitively. Due to these reasons, the fluorescence properties of API are very sensitive to changes in excitation wavelength and solvent.

플라보노이드 갤랑인의 항산화 작용에 대한 분광학적 연구

박형련,박철호 한국피부과학연구원 2017 아시안뷰티화장품학술지 Vol.15 No.4

Purpose: The properties of the flavonoid galangin were investigated via ultravioletvisible (UV-Vis) spectroscopy to obtain further insights into its anti-oxidant behavior. Methods: A UV–Vis spectrophotometer was employed to obtain the absorption spectra of galangin. To clarify the oxidation process of galangin, its spectroscopic behavior was examined not only in different media, such as aerated and deaerated water, but also at different pH values of solution. Results: After the addition of galangin to water, the UV–Vis absorption spectra of the solution changed over time. In addition, the UV–Vis absorption spectra of galangin changed not only in an aerated neutral solution but also in a deaerated basic galangin solution, indicating the occurrence of oxidation. With an increase in the pH values of the solution, the oxidation rate of galangin increased. Spectral changes were not observed for the deaerated acidic solution. Conclusion: The UV–Vis spectroscopy results indicated that galangin is more stable in an acidic aqueous solution than in a basic solution. The reactive oxygen species (ROS) can react with both galangin as well as normal skin cells in a human body as a result of competition. The acidic form of flavonoid is acceptable when flavonoid compounds are used as skin-care products. 목적: 본 연구에서는 항산화 기능을 갖는다고 알려진 플라보노이드 갤랑인의 항산화 특성을 분광학적 방법을 이용하여 고찰해 보고자 한다. 방법: 산성과 염기성 수용액에서의 갤랑인 분자의 흡수스펙트럼을 자외선 분광광도계를 이용하여 측정하였다. 결과: 갤랑인의 흡수스펙트럼 형태는 수용액 중에 존재하고 있는 산소나 이온화된 갤랑인 음이온의 생성에 의해 크게 변화하였는데, 이는 갤랑인이 퀴논 계열로 산화되기 때문이라는 것을 알 수 있었다. 이러한 갤랑인의 산화반응은 용액의 pH에 의존하는데, pH가 증가하여 갤랑인 음이온의 농도가 진해지면 갤랑인이 산화되는 정도는 훨씬 빨라졌다. 반면에 산소가 제거된 산성 수용액 상태에서는 산성도의 세기나 보관시간에 관계없이 흡수피크의 형태가 일정하게 유지되어 산화제가 없는 경우 산화반응이 거의 진행되지 않고 비교적 안정하게 존재할 수 있음을 확인하였다. 결론: 갤랑인과 같은 플라보노이드 화합물을 피부미용제로 이용하는 경우에는 산성 상태에서 보관하고 제조하였을 경우에 훨씬 더 안정한 상태로 존재할 수 있어 더 나은 항산화제의 역할을 할 것으로 판단된다.

Fluorescence Quenching of Norfloxacin by Divalent Transition Metal Cations

박형련,Jung-Ja Seo,신성철,Hyeong Su Lee,박기민 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.9

Fluorescence quenching of norfloxacin (NOR) by Cu2+, Ni2+, Co2+ and Mn2+ was studied in water. The change in the fluorescence intensity and lifetime was measured as a function of quencher concentration at various temperatures. According to the Stern-Volmer plots, the NOR was quenched both by collisions and complex formation with the same quencher. However, the static quenching had a more important effect on the emission. Large static and dynamic quenching constants support significant ion-dipole and orbital-orbital interactions between NOR and cations. The both quenching constants by Cu2+ were the largest among quenchers. Also, quenching mechanism of Cu2+ was somewhat different. The change in the absorption spectra due to the quencher provided information on static quenching. The fluorescence of NOR was relatively insensitive to both the dynamic and static quenching compared with other quinolone antibiotics. This property can be explained by the twisted intramolecular charge transfer.

메탄올-물 혼합용매에서 전도도법에 의한 벤조산 및 치환된 벤조산의 해리에 관한 연구

조민수,박형련,이순기,이계수,이본수,Min Soo Cho,Hyoung Ryun Park,Soon Ki Rhee,Kye Soo Lee,Bon Su Lee 대한화학회 1991 대한화학회지 Vol.35 No.3

25$^{\circ}$C 때 벤조산과 메타 및 파라위치에 할로겐(F, Cl, Br)이 치환된 $pK_a$값을 메탄올-물 혼합용매(0∼80% 메탄올) 중에서 Fuoss-Kraus 식에 근거한 전도도법과 Gelb의 전도도법을 이용하여 결정하였다. 할로겐 치환기에 따른 벤조산의 $pK_a$ 변화를 전자받게 유도효과와 전자주게 공명효과로 복합시킨 치환기 상수(${\sigma}_1$ 및 ${\sigma}_R$)로써 논의하였다. ${\sigma}_1$가 $D^{-1}$에 대하여 양(+)의 기울기를 갖는 직선성을 보인 반면 ${\sigma}_R$은 $D^{-1}$에 대하여 음(-)의 기울기를 갖는 직선성을 보이고 있는데, 이를 field effect의 유전상수 의존성과 할로겐 치환기의 ${\pi}$-고립쌍 전자와 이온화 중심간의 through-space ${\pi}$-상호작용으로 해석하였다. The $pK_a$ values of benzoic acid and meta, para-halogen substituted benzoic acids in MeOH-$H_2O$ mixtures (0∼80% of MeOH) have been determined at 25$^{\circ}$C using a conductometric method on the basis of the Fuoss-Kraus equation, and further verified using modified conductometric method of Gelb. The dependence of $pK_a$ on halogen substituents has been discussed in terms of substituent-constant (${\sigma}$), which is devided into electron-withdrawing inductive contribution (${\sigma}_1$) and electron-donating ${\pi}$-resonance one (${\sigma}_R$). The linear-dependence of ${\sigma}_1$'s on $D^{-1}$ with positive slope and that of ${\sigma}_R$'s on $D^{-1}$ with negative slope have been interpreted on the basis of field effect and through-space interaction of ${\pi}$-lone pair of halogen substituent and ionization center via ${\pi}$-system of benzene ring.

유두컵 라이너의 물리화학적 특성 조사

이정치,박형련,김명선,이정길,이채용 한국임상수의학회 2005 한국임상수의학회지 Vol.22 No.2

This study was carried out to investigate the physical and chemical properties of teat cup liners. The hardness of the liners was 50~67, and their fatigue to failure 38~1,185cycles. The elongation and tensile strength of these liners were about 134kgf/cm2 and 473%, respectively. The infrared spectrum and the gas chromatogram revealed that the liner A was consisted of NR, SBR, and BR, with a composition ratio of 60:20:20 (part per hundred rubber). The raw rubber materials used for liners B to G, on the other hand, were NBR only. However, the liner H was made of silicon rubber. The thermogravimetric analysis showed that the liners tested in this study contained raw rubber material, carbon black, organic compounds and metallic compounds.

일산화탄소가 포함된 에탄올 수용액의 광화학 반응

김희정,이형철,박형련,Kim, Hui Jeong,Lee, Hyeong Cheol,Park, Hyeong Ryeon 대한화학회 1994 대한화학회지 Vol.38 No.4

아르곤과 일산화탄소가 포화된 에탄올 수용액의 광화학 반응을 184.9 nm의 자외선을 이용 연구하였다. 아르곤이 포화된 $1{\times}10^{-2}$M의 에탄올 수용액에서는 acetaldehyde와 2,3-butanediol만이 얻어졌으나, 일산화탄소가 포화된 용액의 광반응에서는 이들 두 가지 생성물 이외에 carboxylation 및 carboxylation반응이 진행되어 ${\alpha}$-hydroxypropionaldehyde, formaldehyde, glyoxal, formic acid, oxalic acid and glyoxylic acid등이 생성되었다. 그러나 에탄올의 농도가 증가한 용액의 광반응에서는 일산화탄소의 존재유무에 관계없이 carboxylation과 carboxylation반응은 관찰되지 않았다. 반응의 결과 얻어진 각 생성물들에 대한 initial quantum yield의 값들을 결정하였으며, 산소가 제거된 에탄올 수용액의 광반응에서 얻은 결과와 비교하여 가능한 반응메카니즘을 제시하였다. The photochemical reaction of aqueous ethanol saturated with argon and carbon monoxide has been investigated using 184.9 nm UV light. The photochemical reaction of $1{\times}10^{-2}$ M aqueous ethanol saturated with argon results in the formation on the acetaldehyde and 2,3-butanediol. The irradiation of the solution saturated with carbon monoxide causes the formation of carbonylation and carboxylation products such as ${\alpha}$-hydroxypropionaldehyde, formaldehyde, glyoxal, formic acid, oxalic acid and glyoxylic acid in addition to above two products. But in the case of concentrated ethanol solutions, the irradiation did not give carbonylation and carboxylation products. The initial quantum yields of the products were determined and probable mechanisms for the reaction were presented on the basis of product analysis.

제57차 추계학술대회 및 총회 : 일반연제 6 ; 피부생물학 : 5-Aminolevulinic Acid (ALA)와 ALA Esters에 의한 Protoporphyrin 9의 발현 및 합성에 관한 연구

이지범,오종훈,박형련,권용현,윤숙정,원영호,이승철 대한피부과학회 2005 초록집 Vol.43 No.20