• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.136-136
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• 2013

High-resolution photoemission spectroscopy (HRPES) measurements were collected and density functional theory (DFT) calculations were conducted to track the coverage dependent variation of the absorption structure of 2-thiophenecarboxaldehyde (C4H3SCHO: TPCA) on the Ge(100) surface at room temperature. In an effort to identify the most probably adsorption structures on the Ge(100) surface, we deposited TPCA molecules at a low coverage and at a high coverage and compared the differences between the electronic features measured using HRPES. The HRPES data provided three possible adsorption structures of TPCA on the Ge(100) surfaces, and DFT calculations were used to determine the plausibility of the structures. HRPES analysis, corroborated by DFT calculations, indicated that an S-dative bonded structure was the most probable adsorption structure at relatively lower coverage levels, the [4+2] cycloaddition structure was the second most probable structure, and the [2+2]-C=O cycloaddition structure was the last probable structure on the Ge(100) surfaces at relatively higher coverage levels.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.647-650
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• 2001

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2169-2170
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• 2011

• Proceedings of the Korean Society of Potoscience Conference
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• 2005.06a
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• pp.134-134
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• 2005

• Archives of Pharmacal Research
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• v.13 no.2
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• pp.126-131
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• 1990

The novel N-phenyl-2-furohydrazonyl chloride 4A and its p-nitro analog 4B have been prepared and identified. The cycloaddition reactions of nitrilimines 5A and 5B, derived by base catalyzed dehydrochlorination of 4A and 4B respectively, to a variety of dipolarophiles were investigated. The results showed that 4A and 4B are usuful precursors for synthesis of differently substituted 3-(2-furyl)-2-pyrazoline derivatives and their pyrazoles and analogs.

• Journal of Photoscience
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• v.2 no.2
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• pp.95-98
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• 1995

The photodimers with cyclobutane rings and C$_2$ symmetry, derived from coumarin (syn, head to tail and anti, head to head) have been calculated by PM3-UHF-CI and Molecular Mechanics force field. The photocycloaddition to coumarin and 5,7-dimethoxycoumarin(DMC) dimers were deduced to be formed by their preferable frontier orbital interactions and via more stable cycloaddition by the C$_3$, C$_4$ bond. These results are consistent with the coumarin dimer model that the theoretical C$_4$-photocyclodimer of coumarin is predicted much more than the experimental C$_4$-photocyclodimer.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3690-3694
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• 2013

The $H_2Ge=Ge:$ and its derivatives ($X_2Ge=Ge:$, X = H, Me, F, Cl, Br, Ph, Ar${\ldots}{\ldots}$) is a new species. Its cycloaddition reactions is a new area for the study of germylene chemistry. The mechanism of the cycloaddition reaction between singlet state Cl2Ge=Ge: and formaldehyde has been investigated with CCSD(T)//MP2/$6-31G^*$ method. From the potential energy profile, it could be predicted that the reaction has only one dominant reaction pathway. The reaction rule presented is that the two reactants first form a fourmembered Ge-heterocyclic ring germylene through the [2+2] cycloaddition reaction. Because of the 4p unoccupied orbital of Ge: atom in the four-membered Ge-heterocyclic ring germylene and the ${\pi}$ orbital of formaldehyde forming a ${\pi}{\rightarrow}p$ donor-acceptor bond, the four-membered Ge-heterocyclic ring germylene further combines with formaldehyde to form an intermediate. Because the Ge: atom in intermediate hybridizes to an $sp^3$ hybrid orbital after transition state, then, intermediate isomerizes to a spiro-Ge-heterocyclic ring compound via a transition state. The research result indicates the laws of cycloaddition reaction between $H_2Ge=Ge:$ and formaldehyde, and laid the theory foundation of the cycloaddition reaction between $H_2Ge=Ge:$ and its derivatives ($X_2Ge=Ge:$, X = H, Me, F, Cl, Br, Ph, Ar${\ldots}{\ldots}$) and asymmetric ${\pi}$-bonded compounds, which is significant for the synthesis of small-ring and spiro-Ge-heterocyclic compounds. The study extends research area and enriches the research content of germylene chemistry.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.30-30
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• 2002

Heating [Cp＊Rh(η²-NO₃)(OTf) (1) and PhC≡CPh in EtOH for 3 h gave a η⁴-cyclobutadienerhodium complex, [Cp＊Rh(η⁴-C₄Ph₄)] (2). Complex 1 reacted with HC=CPh in acetone at room temperature for 3 h to give a (η⁴-cyclobutadiene)-rhodium complex, [Cp＊Rh(η⁴-C₄HPhC=CPh)] (3). Whereas, the reactions of 1 with HC=CCH₂Cl in acetone at room temperature for 3 h gave the triply halide-bridged dinuclear rhodium complex, [Cp＊Rh(μ₂-Cl)₃RhCp＊](OTf) (4). Complexes 2-4 have been structurally characterized by X-ray diffraction.

• Bulletin of the Korean Chemical Society
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• v.18 no.5
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• pp.534-540
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• 1997

4H,6H-Furo[3,4-c]isoxazoles (Ⅰ-Ⅳ), potential fungicides, have been designed and synthesized via intramolecular [2+3] cycloaddition of nitroalkyne 3 as a key step. The broad spectrum of fungicidal activities of furoisoxazoles (Ⅰ-Ⅳ) were observed on plant pathogens at 250 ppm. Furoisoxazoles Ⅱ, Ⅲ with chlorophenyl at 6-position and methyl or alkylated oxime group at 3-position gave effective control of plant diseases. The furoisoxazole Ⅳ with a chlorophenyl group at 4-position also resulted in high fungicidal activities.

• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.233-235
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• 1987

The kinetics of the 1,3-dipolar cycloaddition of p-substituted 3-phenylsydnones 1a-d with DMAD have been investigated. The reaction rates over a temperature range $100-140^{\circ}C$ were measured by UV spectrometry. The reactions found to be second-order overall, insensitive to the dielectric constants of the solvents, and characterized by a large entropy of activation. These findings are consistent with the rate-determining step involving the formation of cyclic transition state 1 and the reaction proposed to be concerted.