• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.943-946
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• 2011

The electronic absorption and surface morphology evolution of two types of molecular double layer thin films, copper phthalocyanine (CuPc) layer deposited on chloro[subphthalocyaninato]boron(III) (SubPc) layer, denoted as SubPc/CuPc, and vice versa, with various thicknesses were investigated using ultraviolet (UV)-visible spectroscopy and atomic force microscopy (AFM). Both types of double layer structures showed similar broadened absorption patterns in the UV-visible region that were consistent with the fitted spectra following simple linear combination of the single layer absorption spectra of the two materials. In contrast, the surface morphology of double layer structures was dependent on the order of deposition. For the CuPc/SubPc structures, surface morphology was characterized by elongated grains, which are characteristic of SubPc thin films, indicating that the morphological influence of the underlying CuPc layer on the subsequent SubPc layer was not large. For the SubPc/CuPc structures, however, the underlying SubPc layer acted as a morphological template for the subsequently deposited CuPc layer. It was also observed that the grain size of the CuPc layer varied according to the thickness of the underlying SubPc layer.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1875-1880
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• 2010

A dicycle pyrazoline derivative, 1-phenyl-5-(p-fluorophenyl)-3,4-($\alpha$-p-fluoro-tolylenecyclohexano) pyrazoline, was synthesized and characterized by elemental analysis, IR, UV-vis, fluorescence spectra and X-ray single crystal diffraction. Density function theory (DFT) calculations were performed by using B3LYP method with 6-$311G^{**}$ basis set. The optimized geometry can well simulate the molecular structure. Vibrational frequencies were predicted, assigned and compared with the experimental values, which suggest that B3LYP/6-$311G^{**}$ method can well predict the IR spectra. Both the experimental electronic absorption spectra and the predicted ones by B3LYP/6-$311G^{**}$ method reveal three electron-transition bands, with the theoretical ones having some red shifts compared with the experimental data. Natural bond orbital analyses indicate that the absorption bands are mainly derived from the contribution of n $\rightarrow\pi^*$ and $\pi\rightarrow\pi^*$ transitions. Fluorescence spectra determination shows that the title compound can emit blue-light at about 478 nm. On the basis of vibrational analysis, the thermodynamic properties of title compound at different temperature have been calculated, revealing the correlations between $C^0_{p,m}$, $S^0_m$, $H^0_m$ and temperature.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.531-538
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• 2014

The quantum mechanical properties of a series of oligo-para-phenylenes (2-11) were characterized using DFT B3LYP/6-311G(d,p) calculations. The global minimum among the various torsional conformers of an oligo-p-phenylene is calculated to be a twist conformation. A less stable planar conformation, in which all the dihedral angles in oligo-p-phenylene are restricted to be planar, has also been calculated. The total electronic energies, normal vibrational modes, Gibbs free energies, and HOMOs and LUMOs of the two different conformations (twisted and planar) of the oligo-p-phenylenes were analyzed. The energy differences between the HOMOs and LUMOs of the substrates are in accord with the maximum absorption peaks of the experimental UV spectra of 2-6. The calculated normal vibrational modes of 2-6 were comparable with their experimental IR spectra.

• Journal of the Korean Wood Science and Technology
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• v.12 no.3
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• pp.35-40
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• 1984

The ultraviolet absorption spectra of AcBr lignin (Acetyl Bromide lignin) from 10 species grown in Mt. Jiri were determined. There were 3 peak positions, at 249nm (max peak), at 267-268 nm (shallow min. peak) and at 280 nm (lower max. peak). The Bjorkman lignin and lignin sulfonic acid spectra had shoulders, but the AcBr lignin had not them. Average absorbances and absorptivities of the AcBr lignins at peak positions were $0.367{\pm}0.0015$, $24.56{\pm}0.0535$, at 249 nm, $0.278{\pm}0.0016$, $18.50{\pm}0.0569$, at 267-268 nm and $0.306{\pm}0.0016$, $20.42{\pm}0.0627$ at 280 nm, respectively.

• Archives of Pharmacal Research
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• v.22 no.2
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• pp.143-150
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• 1999

melatonin (MLT), N-acetyl-5-methoxytryptamine, is mainly secreted by the pineal gland. The ultraviolet (UV), infrared (IR) and 1H-NMR spectra of irradiated and non-irradiated MLT were measured, and phototoxicity tests of MLT, anthracence (positive control) and sodium lauryl sulfate (SLS, negative control) were performed. The methods employed include both in vitro test such as MTS assay using the human fibroblast cell and yeast growth inhibition assay using Candida albicans and in vivo method using the skin of guinea pig. UV absorption spectra and 1H-NMR spectra of MLT were changed by UVA (365 nm, 15 J/$\textrm{cm}^2$), but IR spectra of MLT were not changed. The fifty percent inhibitory concentration (IC50) ratio (UV-/UV+) of MLT was 10. The inhibition zone of irradiated-paper disks treated with MLT was not observed. According to the results of histophathological examination, no pathologic lesion was observed in the non-irradiated group, but slight degeneration of keratinocytes in the epidermis, homorrhage and vasodilation in dermis were observed in the irradiated group. These results indicated that the molecular structure of MLT is altered by UVA to unidentified photoproducts and a moderate phototoxicity of MLT is predicted.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1204-1208
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• 2010

Anion recognition via hydrogen-bonding interactions could be monitored with changes in UV-vis absorption spectra and in some cases easily monitored with naked eye. Urea receptors 1 and 2 connected with both an azo group and a nitrophenyl group as a signaling group for color change proved to be an efficient naked eye receptor for the fluoride ion. The anion recognition phenomena of the receptors 1 and 2 via hydrogen-bonding interactions were investigated through UV-vis absorption and $^1H$ NMR spectra.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1715-1719
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• 2007

New bispsoralen derivatives 5-10, 8-MOP-NHCO(CH2)nCONH-8-MOP (BPSBA-Cn, n = 0, 1, 2, 3, 4 and 5) in which 5 position of an 8-methoxypsoralen (8-MOP) is linked by various lengths of bisamide polymethylene chain to 5 position of the other 8-MOP, have been synthesized by the amidation of 5-amino-8-methoxypsoralen (12) with α,ω-alkanoyl dichloride. Photophysical properties of their derivatives including π?π stacking interaction between the two aromatic moieties were investigated by UV absorption and fluorescence emission spectra. Efficient ring-ring stacking interactions have been observed in BPSBA-C4 (9) from the percent hypochromism (%H) of the models.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.277-280
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• 1997

It is important to investigate the molecular arrangement and the orientational distribution in the study of LB films. Polarized UV/visible absorption spectra make it possible to reveal the molecular arrangement and the orientational distribution. It is clarified that the PAAS LB films have specific directions in the molecular arrangement and the orientational distribution, which art different in intensity corresponding to the surface pressure. Unpolarized UV/visible absorption spectra reveal that the surface pressure is proportional to the finn thickness and is related to the molecular orientation. Current-Voltage(I-V) measurements provide that the current decreases as the surface pressure increases and there are certain phenomena called switching phenomena. Switching effort indicates that the current flows in high conductivity during on-state and suddenly decreases into low conductivity during off-state.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.475-478
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• 2000

Maxwell displacement current(MDC) was generated when the area per molecule was about 140${\AA}$$^2$and 100${\AA}$$^2$. MDC were investigated in connection with monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles. The absorption spectra of polyamic acid containing p-methoxyazobenzene in a mixture of N,N-dimethylacetamide(DMAc) and benzene(1:1 by volume) solution was induced photoisomerization by UV and visible light irradiation. The precursor LB film was heated in a vacuum dry oven at 120$^{\circ}C$ in order to convert it into the LB film of polyimide. The absorption spectra of LB films were also induced photoisomerization by UV and visible light irradiation.

• Journal of Photoscience
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• v.12 no.1
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• pp.11-15
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• 2005

The mechanism of interaction of two drugs viz., amoxicillin and cloxacillin with bovine serum albumin has been investigated using fluorescence absorption and circular dichroism spectroscopy. The quenching mechanism of fluorescence of bovine serum albumin by amoxicillin and cloxacillin was discussed. The binding sites number n and apparent binding constant Kwere measured by fluorescence quenching method. The thermodynamic parameters obtained from data at different temperatures were calculated. The distance r between donor (bovine serum albumin) and acceptor (amoxicillin and cloxacillin) was obtained according to Forster theory of non-radiative energy transfer. The effect of common ions on binding constant was also investigated. The results of synchronous fluorescence spectra, UV-vis absorption spectra and circular dichroism of BSA in presence of amoxicillin and cloxacillin show that the conformation of bovine serum albumin changed