Hee-Joon Kim

Kumoh National Institute of Technology, Sŏul, Seoul, South Korea

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Publications (40)193.91 Total impact

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    ABSTRACT: Capture and reforming fume gases from atmosphere became an ultimate task recently. Photocatalytic reduction to useful compounds is a key to the future. Photoinduced reduction of carbon dioxide and ammonia aqueous solution into amine compounds at room temperature and atmospheric pressure using transition metal doped titanium dioxide is presented in this paper. UV-visible spectra showed a high absorbance at 200 nm wavelength which is a characteristic of urea. High Performance Liquid Chromatography revealed presence of amine compounds and urea was found a main product of photocatalytic reaction
    ICETI 2014, Taiwan; 11/2014
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    ABSTRACT: Green/biobased biofuels derived from renewable resources are in the area special interest recently. In this paper methanol artificial photosynthesis using Iron doped TiO2 powder is reported. Methanol was fabricated in simple photocatalytic reactor under 300W tungsten halogen lamp irradiation. Photocatalyst was dispersed in water, CO2 gas was applied under different flow rate at continuous mechanical stirring. The optimum ethanol yield condition (amount of catalyst, pH, TiO2 particle size, stirring speed) was found. Iron doped TiO2 performed good selectivity for methanol photosynthesis. Experimental results showed that, Iron doped TiO2 is much more effective for methanol photosynthesis than bare TiO2.
    Journal of Biobased Materials and Bioenergy 04/2014; 8(April):165-169. DOI:10.1166/jbmb.2014.1429 · 0.59 Impact Factor
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    ABSTRACT: Reactions of trans-dihydroxo(meso-tetraphenylporphyrinato)tin(IV) [Sn(TPP)(OH)2] with β-diketones such as acetylacetone (1), dibenzoylmethane (2), 1-phenylbutane-1,3-dione (3), or 4,4-dimethyl-1-phenylpentane-1,3-dione (4) were studied. All reactions afforded dicarboxylato tin(IV) porphyrin complexes [Sn(TPP)(O2CR)2] (R = Me, Ph, t-Bu) and ketonic compounds due to the C–C bond cleavage of β-diketones. The products were characterized by 1H NMR spectroscopy and ESI mass spectrometry, and further proved by X-ray crystallographic analysis of Sn(TPP)(O2CCH3)2. Possible reaction mechanisms involving four-centered intermediate species are discussed, in which the C–C and O–H bonds are cleaved along with the simultaneous formation of (Sn)O–C and H–C bonds.
    Tetrahedron Letters 11/2012; 53(47):6456–6459. DOI:10.1016/j.tetlet.2012.09.075 · 2.39 Impact Factor
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    ABSTRACT: This study evaluates the potential application of tin porphyrin- and C(60) aminofullerene-derivatized silica (SnP/silica and aminoC(60)/silica) as (1)O(2) generating systems for photochemical degradation of organic pollutants. Photosensitized (1)O(2) production with SnP/silica, which was faster than with aminoC(60)/silica, effectively oxidized a variety of pharmaceuticals. Significant degradation of pharmaceuticals in the presence of the 400-nm UV cutoff filter corroborated visible light activation of both photosensitizers. Whereas the efficacy of aminoC(60)/silica for (1)O(2) production drastically decreased under irradiation with λ > 550 nm, Q-band absorption caused negligible loss of the photosensitizing activity of SnP/silica in the long wavelength region. Faster destruction of phenolates by SnP/silica and aminoC(60)/silica under alkaline pH conditions further implicated (1)O(2) involvement in the oxidative degradation. Direct charge transfer mediated by SnP, which was inferred from nanosecond laser flash photolysis, induced significant degradation of neutral phenols under high power light irradiation. Self-sensitized destruction caused gradual activity loss of SnP/silica in reuse tests unlike aminoC(60)/silica. The kinetic comparison of SnP/silica and TiO(2) photocatalyst in real wastewater effluents showed that photosensitized singlet oxygenation of pharmaceuticals was still efficiently achieved in the presence of background organic matters, while significant interference was observed for photocatalyzed oxidation involving non-selective OH radical.
    Environmental Science & Technology 08/2012; 46(17):9606-13. DOI:10.1021/es301775k · 5.48 Impact Factor
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    Atul P Singh, Hee-Joon Kim
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    ABSTRACT: In the crystal structure of the title compound, [Sn(C(44)H(28)N(4))(CH(3)O(3)S)(2)]·3CHCl(3), the Sn(IV) ion is located on an inversion center and is octa-hedrally coordinated. The porphyrin N atoms occupy the equatorial positions while the axial positions are occupied by the O atoms of the methane-sulfonate anions. The phenyl rings make dihedral angles of 77.02 (13) and 87.89 (14)° with the porphyrin ring. Of the three solvent chloro-form mol-ecules, one is disordered over a twofold rotation axis. In the crystal a three-dimensional assembly is accomplished via C-H⋯O hydrogen bonds between the H atoms of the phenyl groups in the porphyrin ring and the O atoms of the methane-sulfonate ligands.
    Acta Crystallographica Section E Structure Reports Online 05/2012; 68(Pt 5):m626. DOI:10.1107/S1600536812015875 · 0.35 Impact Factor
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    ABSTRACT: The photophysical behavior of a series of heterometallic arrays made of a central Sn(IV) porphyrin connected respectively, to two (SnRu(2)) four (SnRu(4)), or six (SnRu(6)) ruthenium porphyrin units has been studied in dichloromethane Two different motifs connect the ruthenium porphyrin units to central tin porphyrin core, axial coordination via ditopic bridging ligands and/or coordination to peripheral pyridyl groups of the central porphyrin ring A remarkable number of electron transfer processes (photoinduced charge separation and recombination processes) have been time-resolved using a combination of emission spectroscopy and last (nanosecond) and ultrafast (femtosecond) absorption techniques In these systems both types of molecular components can be selectively populated by light absorption In all the arrays the local excited states of these units (the tin porphyrin singlet excited state and the ruthenium porphyrin triplet state) arc quenched by electron transfer leading to a charge-separated state where the ruthenium porphyrin unit is oxidized and the tin porphyrin unit is reduced For each array the two forward electron transfer processes as well as the charge recombination process leading back to the ground state have been kinetically resolved the rate constants obey standard free-energy correlations with the forward processes lying in the normal free-energy regime and the back reactions in the Marcus inverted region The comparison between the trimeric (SnRu(2)) and pentameric (SnRu4) arrays shows that all the electron transfer processes are faster in the latter than in the former system This can be rationalized in terms of differences in electronic factors (due to the different connecting motifs) and driving force In less polar solvents, such as toluene, the energy of the charge-separated states is substantially lifted, leading to a switch (from electron transfer to triplet energy transfer) in the deactivation mechanism of the excited ruthenium triplet
    The Journal of Physical Chemistry B 11/2010; 114(45):14273-82. DOI:10.1021/jp9107798 · 3.38 Impact Factor
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    ABSTRACT: Hydrogen was successfully produced under visible light irradiation in a tin porphyrin (SnP)-sensitized TiO2 system in the wide pH range (pH 3–11) although SnP hardly adsorbs on TiO2. The number of H2 produced in the SnP/TiO2 system after 9 h irradiation corresponds to the turnover number of 410. The apparent photonic efficiency for H2 evolution was estimated to be 35% with the monochromatic radiation of 550 ± 10 nm. The photochemical production of hydrogen is mediated through the formation of the π-radical anion (SnP˙−) that subsequently transfers electron to TiO2. The photogenerated SnP˙− was monitored by transient absorption spectroscopy and its lifetime is long enough to survive the slow diffusion from the solution bulk to the TiO2 surface, which makes the adsorption of SnP on TiO2 not required for hydrogen production. This is clearly contrasted with the common ruthenium complex-sensitized TiO2 system where the adsorption of the sensitizer complex is essentially required and the hydrogen production is limited to the acidic condition where the adsorption of the sensitizers on TiO2 is allowed. The photocatalytic activity of SnP was mainly attributed to the Q-band (500–650 nm), not to the Soret band (420–430 nm) of which absorption intensity is much higher.
    Energy & Environmental Science 10/2010; 3(11):1789-1795. DOI:10.1039/C0EE00205D · 15.49 Impact Factor
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    Hee-Joon Kim
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    ABSTRACT: In the title compound, C(31)H(34)N(2)O(4), the two pyrrole rings are bent around the central methyl-ene C atom, making a dihedral angle of 64.83 (7)°. In the crystal, mol-ecules are linked into dimers via N-H⋯O=C hydrogen bonds. These dimers are packed through π⋯π inter-actions between neighboring pyrrole rings with a separation between the mean planes of symmetry-related pyrrole rings of 3.61 (2) Å and a centroid-centroid distance of 4.33 Å. Parallel phenyl groups in neighboring dimers also exhibit efficient π⋯π inter-actions, characterized by an inter-plane separation of 3.378 (8) Å and a centroid-centroid distance of 3.97 Å.
    Acta Crystallographica Section E Structure Reports Online 03/2010; 66(Pt 3):o566. DOI:10.1107/S1600536810004459 · 0.35 Impact Factor
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 02/2010; 33(6). DOI:10.1002/chin.200206106
  • Atul P. SINGH, Hee-Joon KIM
    X-ray Structure Analysis Online 01/2010; 26:23-24. DOI:10.2116/xraystruct.26.23
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    Hee Jung Kim, Atul P Singh, Hee-Joon Kim
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    ABSTRACT: In the centrosymmetric title compound, C(64)H(62)N(4), the two phenyl-ethynyl groups lie at diagonal meso positions. The 24-membered porphyrin has in-plane distortion with respect to the mean plane of the macrocycle and two intra-ring bifurcated N-H⋯(N,N) hydrogen bonds occur. The dihedral angles between the phenyl rings in the phenyl-ethynyl group and the 3,5-bis-(tert-but-yl)phenyl group with respect to the mean plane of the porphyrin are 17.2 (2) and 59.2 (3)°. The tert-butyl groups are disordered over two sets of sites in a 0.661 (13):0.339 (13) ratio.
    Acta Crystallographica Section E Structure Reports Online 12/2009; 65(Pt 12):o3004-5. DOI:10.1107/S1600536809045954 · 0.35 Impact Factor
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    ABSTRACT: Photochromic fluorophore Sn(TTP)(DTE)2 , in which two phenolic derivatives of 1,2-dithienylethene are axially coordinated to (5,10,15,20-tetratolylporphyrinato)tin(IV) in trans position, has been synthesized and fully characterized by various spectroscopic methods. We have also investigated the photoregulated fluorescence switching behavior of Sn(TTP)(DTE)2 . The fluorescence of the porphyrin macrocycle in Sn(TTP)(DTE) 2 greatly depends on the state of the 1,2-dithienyletene photochromic switch. In the open state (Sn(TTP)(o-DTE)2), the porphyrin exhibits high fluorescence intensity at 609 and 664 nm when excited at 410 nm. When the photocyclization reaction was carried out by irradiating Sn(TTP)(o-DTE)2 with the UV light (approximately 365 nm), the fluorescence intensity of the porphyrin macrocycle decreased. Back irradiation with visible light at wavelengths greater than 500 nm regenerated Sn(TTP)(o-DTE)2 and almost restored the original fluorescence spectrum. The fluorescence intensity of the porphyrin fluorophore is efficiently regulated by photochromic switching between Sn(TTP)(o-DTE)2 and Sn(TTP)(c-DTE)2 in several cycles, clearly demonstrating that the Sn(TTP)(DTE)2 can act as a system for reversible data processing using fluorescence as the detection method.
    Inorganic Chemistry 05/2008; 47(7):2411-5. DOI:10.1021/ic701390m · 4.79 Impact Factor
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    ABSTRACT: We report octupolar trisporphyrin conjugates, derived from the symmetrical functionalization of a triphenylamine core with three ethynylporphyrin wings, exhibiting largely enhanced two-photon absorption (TPA) compared to the porphyrin monomers. Octupolar trisporphyrin conjugate tris-H2P was synthesized by the Pd(0)-catalyzed Sonogashira cross-coupling reaction of tris(4-iodophenyl)amine with 5,10,15-tri-(p-tolyl)-20-ethynylporphyrin, and fully characterized by various spectroscopic methods and elemental analysis. The optimized geometry of tris-H2P obtained by semi-empirical AM1 calculations reveals that tris-H2P adopts a propeller-shaped structure. Our photophysical studies strongly manifest that the trisporphyrin conjugates are promising octupolar fluorophores with effective π-conjugation over the porphyrin wings through the octupolar core. The trisporphyrin conjugates exhibit much larger TPA cross-section values in comparison with the monomers; the TPA cross-section σ(2) value of tris-ZnP (11,800 GM) exceeds that of mono-ZnP (630 GM) by about 20 times.Graphical abstract
    Tetrahedron 03/2008; 64(12):2733-2739. DOI:10.1016/j.tet.2008.01.068 · 2.82 Impact Factor
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    ABSTRACT: Visible light photocatalysis using water-soluble tin porphyrin (s-SnP, [Sn(OH 2) 2 (TPy H P)](NO 3) 6) and water-insoluble tin porphyrin Sn(OH) 2 (TPP) (ins-SnP) immobilized on SiO 2 (hetero-SnP) was investigated. The visible light photocatalytic activities of s-SnP and hetero-SnP were demonstrated successfully for the degradation of 4-chlorophenol (4-CP) and acid orange 7 (AO7) in water. The visible light activity of hetero-SnP increased with the ins-SnP loading and was saturated above 77 mg/g-SiO 2 , which corresponded to the homogeneous concentration of [ins-SnP]) 50 µM. It is the Q band of SnP (500-650 nm) that is photocatalytically active under visible light, not the Soret band (420-430 nm) whose absorption intensity is much higher. When applied to the degradation of 4-CP and AO7, hetero-SnP was particularly stable and could be used repeatedly without losing the activity whereas the activity of s-SnP was reduced gradually with repeated uses. The photocatalytic degradation reactions of 4-CP, AO7, and other organic substrates were studied systematically to show that the operating mechanisms are very different depending on the kind of substrates. The properties and activities of s-SnP and hetero-SnP as visible light photocatalysts were investigated in various ways and discussed in detail.
    The Journal of Physical Chemistry C 01/2008; 112(2). DOI:10.1021/jp0747151 · 4.84 Impact Factor
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    ABSTRACT: The reversible formation of cucurbit[8]uril (CB[8])-stabilized charge-transfer (CT) complex on gold, which can be regulated by electrochemical stimuli, is reported. A viologen-based thread molecule with a thiol terminus was designed to synthesise a stable CB[8]-threaded [2]pseudorotaxane (5 ). A mixed self-assembled monolayer (SAM) of 5 and 3-mercaptopropionic acid (3-MPA) on gold was prepared and characterised by reflectance FT-IR spectroscopy. The formation and disruption of a CT complex on surface was investigated by cyclic voltammetry with the SAM on gold as a working electrode in a supporting electrolyte solution containing 2,6-dihydroxynaphthalene (DHNp). The cathodic peak was shifted to a more negative potential (ΔE∼40 mV) when compared with that measured without DHNp in the electrolyte, which confirmed the formation of a CT complex on gold upon immersion of the SAM of 5 on gold in the supporting electrolyte containing DHNp. When the viologen unit was reduced, the CT complex was destroyed and the electron-rich guest molecule was released. Upon reoxidation of the reduced viologen unit, however, the CT complex was slowly reformed.
    Supramolecular Chemistry 01/2008; 20(1–2):149-155. DOI:10.1080/10610270701742587 · 2.13 Impact Factor
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    ABSTRACT: Photophysical properties of a newly-synthesized porphyrin derivative, trans-bis(ferrocene carboxylato)- (5,10,15,20-tetraphenylporphyrinato)tin(IV) [Sn(TPP)(FcCOO)2] were investigated by means of steady-state and fs-time resolved laser spectroscopic techniques, and compared with those of a standard molecule, transdichloro( 5,10,15,20-tetraphenyl-porphrinato)tin(IV) [Sn(TPP)Cl2]. The fluorescence spectrum of Sn(TPP)- (FcCOO)2 was observed to exhibit dual emission bands originating from the S2-state and the S1-state, which was greatly quenched as compared to those of Sn(TPP)Cl2. The fs-time resolved fluorescence and transient absorption spectroscopic measurements revealed that the fluorescence quenching is due to formation of the long-lived charge transfer state by intramolecular electron transfer from ferrocene to the S2-excited SnTPP in addition to the enhanced non-radiative deactivation processes.
    Bulletin- Korean Chemical Society 11/2007; 28(11):1967-72. DOI:10.5012/bkcs.2007.28.11.1967 · 0.84 Impact Factor
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    ABSTRACT: trans-Bis(ferrocenecarboxylato)(5,10,15,20-tetraphenylporphyrinato)tin(IV) complex Sn(TPP)(FcCOO)2 has been synthesized and fully characterized. The X-ray structural analysis of Sn(TPP)(FcCOO)2 reveals that the tin(IV) center is octahedrally coordinated by the porphyrin occupying the square base and axial coordination of two ferrocenecarboxylato ligands in an anti orientation with respect to each other. The Fe(II) center of the ferrocenecarboxylato ligand lies 5.7Å from the tin(IV) center of the porphyrin ring. The cyclic voltammogram of Sn(TPP)(FcCOO)2 exhibits three distinctive redox couples consisting of one oxidative wave and two reductive waves due to the ferrocenecarboxylato ligands and the porphyrin ring, respectively.
    Polyhedron 07/2007; 26(12):2517-2522. DOI:10.1016/j.poly.2006.12.023 · 2.05 Impact Factor
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    ABSTRACT: A new class of nanostructures were fabricated by one-step hydrothermal reaction of a mixture solution of TiO2 anatase powder and a Sn-porphyrin, trans-dihydroxo[5,10,15,20-tetrakis(p-tolyl)porphyrinato]- tin(IV) [SnTTP], and they were found to be well-crystalline trititanate (H2Ti3O7)-type multilayered nanofibers (TiNFs) intercalated by SnTTP which have lengths in the range of 0.5-1 ím with an average diameter of approximately 50 nm. Based on the femtosecond-diffuse reflectance transient absorption and photoluminescence spectroscopic measurements, the SnTTP-intercalated TiNFs were observed to exhibit efficient optoelectronic properties such as photoinduced electron transfer from deep surface states of trititanate layer to SnTTP, forming an anion radical SnTTP.¥- rapidly in a few picoseconds. These results infer that electrons and holes are effectively separated in the SnTTP-TiNFs upon illumination, and consequently remarkable UV-visible light-sensitive photocatalytic activities as compared to those of free TiNFs and SnTTP, suggesting that the SnTTP-intercalated TiNFs have potential application in development of efficient artificial photosynthetic systems and photoelectronic materials.
    Chemistry of Materials 06/2007; 19:1984. DOI:10.1021/cm0629863 · 8.54 Impact Factor
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
    Angewandte Chemie International Edition 02/2007; 46(1-2):210-3. DOI:10.1002/anie.200603149 · 11.34 Impact Factor
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    ABSTRACT: A novel thermochromic organic compound, 1,5-bis(hydroxyethylamino)-2,4-dinitrobenzene (BDB), was synthesized and characterized using X-ray diffraction, differential scanning calorimetry, visible and infrared spectroscopy. It was observed that BDB exists in two different crystal structures of A- and B-forms at room temperature. In each crystal structure, there exist intra- and intermolecular hydrogen bonds between hydroxy, amino, and nitro groups. As the temperature is increased, the color of BDB crystalline powder changes from yellow to orange. The yellow color was recovered for a specific period of time when it is cooled again, indicating that thermochromism of BDB in the solid state is reversible. Both crystals of A- and B-forms are transformed to the C-form crystal at the transition temperature. From the results of X-ray diffraction, thermal data, and infrared spectra, it is suggested that the thermochromism of BDB originates from the crystal-to-crystal transition accompanying with the configurational transformation between nitro-form and acid-form via intramolecular hydrogen transfer.
    Journal of Molecular Structure 12/2006; 825(1):70-78. DOI:10.1016/j.molstruc.2006.04.025 · 1.60 Impact Factor

Publication Stats

2k Citations
193.91 Total Impact Points

Institutions

  • 2004–2014
    • Kumoh National Institute of Technology
      • Department of Applied Chemistry
      Sŏul, Seoul, South Korea
  • 1993–2010
    • Pohang University of Science and Technology
      • • Department of Chemistry
      • • School of Environmental Science and Engineering
      • • National Creative Research Initiative Center for Smart Supramolecules and Department of Chemistry
      Geijitsu, North Gyeongsang, South Korea
  • 2006
    • Sungkyunkwan University
      • Institute of Basic Science
      Sŏul, Seoul, South Korea