A5077033632- Photochemistry and Electron Transfer Studies
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Porphyrin and Phthalocyanine Chemistry
- Metal complexes synthesis and properties
- Molecular Junctions and Nanostructures
- Lanthanide and Transition Metal Complexes
- Organic Light-Emitting Diodes Research
- Spectroscopy and Quantum Chemical Studies
- Photosynthetic Processes and Mechanisms
- Supramolecular Chemistry and Complexes
- Luminescence and Fluorescent Materials
- Electrochemical Analysis and Applications
- Metal-Catalyzed Oxygenation Mechanisms
- Crystallography and molecular interactions
- Mass Spectrometry Techniques and Applications
- Organometallic Complex Synthesis and Catalysis
- Nanocluster Synthesis and Applications
- Hemoglobin structure and function
- Catalytic Processes in Materials Science
- Electrochemical sensors and biosensors
- Low-power high-performance VLSI design
- Various Chemistry Research Topics
- Semiconductor Lasers and Optical Devices
- Advanced Photocatalysis Techniques
National Taiwan University
2002-2020
National Taiwan Normal University
2005-2020
Purdue University West Lafayette
2010
Institute of Chemistry, Academia Sinica
1946-2007
Madurai Kamaraj University
2002-2007
National Dong Hwa University
2006
Soochow University
2006
Chung Yuan Christian University
2006
University of Minnesota
2005
Twin Cities Orthopedics
2005
Electron coupling through a β strand has been investigated by measurement of the intramolecular electron-transfer (ET) rates in ruthenium-modified derivatives barrel blue copper protein Pseudomonas aeruginosa azurin. Surface histidines, introduced on methionine-121 mutagenesis, were modified with Ru(2,2′-bipyridine) 2 (imidazole) 2+ complex. The Cu + to Ru 3+ rate constants yielded distance-decay constant 1.1 per angstrom, value close 1.0 angstrom predicted for electron tunneling an...
The rates of Ru(His33)cytochrome c electron-transfer (ET) reactions have been measured over a driving-force range 0.59 to 1.89 eV. dependence Fe2+ → Ru3+ ET in RuL2(im)(His33)cyt [L = 2,2'-bipyridine (bpy), 4,4',5,5'-tetramethyl-2,2'-bipyridine (4,4',5,5'-(CH3)4-bpy), 4,4'-dimethyl-2,2'-bipyridine (4,4'-(CH3)2-bpy), 4,4'-bis(N-ethylcarbamoyl)-2,2'-bipyridine (4,4'-(CONH(C2H5))2-bpy), 1,10-phenanthroline (phen); im imidazole] is well described by semiclassical theory with kmax 2.7 × 106 s-1...
Self-assembly of rhenium(I)-based molecular rectangles containing long alkyl chains has been achieved in one-pot synthesis by solvothermal methods. An enormous enhancement the emission intensity, quantum yield, and lifetime observed when solvent medium is changed from organic to aqueous. Addition water favors aggregation Re(I) rectangle resulting luminescence enhancement, this phenomenon traced out using light scattering techniques.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLong-range electron transfer in ruthenium-modified cytochrome c: evaluation of porphyrin-ruthenium electronic couplings the Candida krusei and horse heart proteinsMichael J. Therien, Mary Selman, Harry B. Gray, I Jy Chang, R. WinklerCite this: Am. Chem. Soc. 1990, 112, 6, 2420–2422Publication Date (Print):March 1, 1990Publication History Published online1 May 2002Published inissue 1 March...
The excited-state relaxation dynamics of a synthetic porphyrin, ZnCAPEBPP, in solution, coated on glass substrate as solid films, mixed with PMMA and sensitized nanocrystalline TiO2 films were investigated by using femtosecond fluorescence up-conversion spectroscopy excitation the Soret band, S2. We found that S2 → S1 electronic ZnCAPEBPP solution occurs 910 690 fs, respectively, but it becomes extremely rapid, <100 due to formation porphyrin aggregates. When probed state transients show...
A series of neutral luminescent molecular rectangles [[Re(CO)(3)(mu-bpy)Br][Re(CO)(3)(mu-L)Br]](2) (1-4) having fac-Re(CO)(3)Br as corners and 4,4'-bipyridine (bpy) the bridging ligand on one side other bipyridyl ligands varying length (L) have been synthesized characterized. The crystal structure 1 shows a rectangular cavity with dimensions 11.44 x 7.21 A. When size is tuned from to 4, dimension 11.4 20.8 could be achieved, revealed by modeling. These exhibit luminescence in solution at...
The kinetics of electron transfer from the triplet-excited Zn-porphyrin to a Ru(NH(3))(5)(His-33)(3+) complex have been measured in Zn-substituted ruthenium-modified cytochrome c under denaturing conditions. In folded protein, electron-tunneling rate constant is 7.5 x 10(5) s(-1). As protein denatured with guanidine hydrochloride, faster adiabatic electron-transfer reaction appears (4.0 10(6) s(-1), [guanidine hydrochloride] = 5.4 M) that limited by intrachain diffusion bring and Ru into...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron transfer in ruthenium/zinc porphyrin derivatives of recombinant human myoglobins. Analysis tunneling pathways myoglobin and cytochrome cDanilo R. Casimiro, Luet L. Wong, Jorge Colon, Thomas E. Zewert, John H. Richards, I Jy Chang, Jay Winkler, Harry B. GrayCite this: J. Am. Chem. Soc. 1993, 115, 4, 1485–1489Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Published inissue 1 February...
Effectiveness of previous SRAM leakage reduction techniques vary significantly as the variation gets worse with process and temperature fluctuation. This paper proposes a simple circuit technique that adaptively trades off overhead energy for maximum savings under severe variations. The proposed run-time on-die caches considers architectural access behavior to determine how often blocks should enter sleep mode. A self-decay generates periodic pulse an adaptive period, which puts array into...
UV-visible absorption and AFM studies suggest that carboxyphenylethynyl zinc porphyrins aggregate on nanocrystalline TiO2 surfaces in an H-type fashion.
The chemical compositions of seven essential oils from Taiwan were analyzed by gas chromatography-mass spectrometry. eluates identified matching the mass fragment patents to National Institute Standards and Technology (NIST) 08 database. quantitative analysis showed that major components lemon verbena are geranial (26.9%) neral (23.1%); those sweet marjoram γ-terpinene (18.5%), thymol methyl ether (15.5%), terpinen-4-ol (12.0%); clove basil eugenol (73.6%), β-(Z)-ocimene (15.4%); patchouli...
Alkoxy-bridged rhenium(I) rectangles [{(CO)3Re(μ-OR)2Re(CO)3}2(μ-bpy)2] (1, R = C4H9; 2, C8H17; 3, C12H25; bpy 4,4'-bipyridine) comprising long alkyl chains form optically transparent aggregates and exhibit luminescence enhancement in the presence of water. The aggregation Re(I)-rectangle was followed using a light-scattering technique. Presumably, enhanced efficiency resulted from restriction torsional molecular motion aggregates. In addition, rate bimolecular quenching Re(I)-aggregates...
The relaxation dynamics of two transition-metal complexes, [Ru(bpy)3]2+ and [Ru(bpy)3(mcbpy)]2+, in ethanol solution poly(methyl methacrylate) (PMMA) TiO2 films have been investigated with time-resolved emission femtosecond transient absorption spectroscopy. lifetime a degassed was determined to be 700 ns; describe the self-quenching kinetics due aggregation, three decay coefficients, 5.3, 70, 220 ns, were obtained for [Ru(bpy)3]2+/PMMA film. electron transfer through space [Ru(bpy)3]2+/TiO2...
Undecanuclear silver clusters [Ag11(μ9-Se)(μ3-Br)3{Se2P(OR)2}6] (R = Et, iPr, 2Bu) were isolated from the reaction of [Ag(CH3CN)4](PF6), NH4[Se2P(OR)2], and Bu4NBr in a molar ratio 4:3:1 CH2Cl2 at −20 °C. Clusters characterized by elemental analysis, NMR spectroscopy (1H, 31P, 77Se), positive FAB mass spectrometry, X-ray crystallography isopropyl derivative. Structural elucidations revealed that Ag11Se core geometry is selenide-centered, slightly distorted 3,3,4,4,4-pentacapped trigonal...
Six ruthenium complexes, [Ru(bpy)3]2+ (1), [Ru(bpy)2(deeb)]2+ (2), [Ru(deeb)2(dmbpy)]2+ (3), [Ru(deeb)2(bpy)]2+ (4), [Ru(deeb)3]2+ (5), and [Ru(deeb)2(bpz)] 2+ (6) (bpy: 2,2′-bipyridine; deeb: 4,4′-diethylester-2,2′-bipyridine; dmbpy: 4,4′-dimethyl-2,2′-bipyridine, bpz: 2,2′-bipyrazine), have been employed to sensitize photochemical oxidation of bromide bromine. The potential for complexes 1–6 are 1.26, 1.36, 1.42, 1.46, 1.56, 1.66 V vs SCE, respectively. bimolecular rate constants the...
Three clusters [Ag11(mu9-Se)(mu3-I)3{Se2P(OR)2}6] (R = Et, 1; iPr, 2; 2Bu, 3) were isolated from the reaction of [Ag(CH3CN)4](PF6), NH4[Se2P(OR)2], and Bu4NI in a molar ratio 4:3:1 CH2Cl2 47-55% yield. Compounds 1 2 can also be synthesized with high yield Ag10(Se)[Se2P(OR)2]8 8 equiv Bu4NI. In positive fast atom bombardment mass spectra 1-3, two major peaks that correspond to intact molecule loss an iodide ion, [Ag11(mu9-Se)(mu3-I)(2){Se2P(OR)2}6]+, diselenophosphate ligand,...
Three consecutive bimolecular reactions are employed to photocatalyze bromide oxidation bromine. The system consists of a ruthenium(II) complex, [Ru(deeb)2(dmbpy)]2+ (deeb = 4,4′-diethylester-2,2′-bipyridine; dmbpy 4,4′-dimethyl-2,2′-bipyridine), 4-bromobenzenediazonium tetrafluoroborate (ArN2BF4), and Br–. Varying reagent concentrations allowed us optimize the sequence for product formation. electronically excited ruthenium complex (*Ru) reacts first with ArN2BF4 produce ruthenium(III)...
The rhenium-based rectangles [{Re(CO)3(μ-bpy)Br}{Re(CO)3(μ-L)Br}]2 (I, L = 4,4′-dipyridylacetylene (dpa); II, 4,4′-dipyridylbutadiyne (dpb); III, 1,4-bis(4′-pyridylethynyl)benzene (bpeb); bpy 4,4′-bipyridine) are emissive in solution at room temperature. presence of extended π conjugation leads to an increase electron delocalization, which, turn, results improved luminescence and lower nuclear reorganization energy. These rectangles, upon electronic excitation, undergo facile transfer (ET)...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPressure Effects on the Rates of Intramolecular Electron Transfer in Ruthenium-Modified Cytochrome c. Role Intervening Medium Tuning Distant Fe2+:Ru3+ Electronic CouplingsMartin Meier, Rudi van Eldik, I Jy Chang, Gary A. Mines, Deborah S. Wuttke, Jay R. Winkler, and Harry B. GrayCite this: J. Am. Chem. Soc. 1994, 116, 4, 1577–1578Publication Date (Print):February 1, 1994Publication History Published online1 May 2002Published inissue 1 February...
ADVERTISEMENT RETURN TO ISSUEArticleNEXTPhotoinduced Electron Transfer in Iridium(spacer)pyridinium ComplexesRamy S. Farid, I-Jy Chang, Jay R. Winkler, and Harry B. GrayCite this: J. Phys. Chem. 1994, 98, 20, 5176–5179Publication Date (Print):May 1, 1994Publication History Published online1 May 2002Published inissue 1 1994https://pubs.acs.org/doi/10.1021/j100071a001https://doi.org/10.1021/j100071a001research-articleACS PublicationsRequest reuse permissionsArticle...
The International Chemistry Olympiad (IChO) is celebrating its 50th anniversary in 2018. Since 1968, 30 countries have hosted this prestigious event for preuniversity students, and 83 participated annual tournament. aim of the IChO includes promoting students' interest science, particular, popularization chemistry. For jubilee celebration, returning to birthplace, Czech Republic Slovakia.