Excited-state metal-to-ligand charge transfer dynamics of a ruthenium(II) dye in solution and adsorbed on TiO2 nanoparticles from resonance Raman spectroscopy

The dynamics of metal-to-ligand charge transfer (MLCT) in a cis-bis(4,4'-dicarboxy-2,2'-bipyridine)-bis(isothiocyanato)ruthenium(II) dye (N3) are compared for the free dye in solution and the dye adsorbed on the surface of the TiO(2) nanoparticles from resonance Raman spectroscopy. The 544-nm MLCT absorption band of N3 adsorbed on TiO(2) is slightly blue-shifted from that of the free N3, indicating a weak electronic coupling between N3 and TiO(2). The resonance Raman spectra of N3 and the N3|TiO(2) complex obtained upon excitation within the lowest-lying MLCT singlet state of the dye are similar except for slight shifts in band positions. Resonance Raman cross sections have been obtained for the vibrational modes of both N3 and N3|TiO(2) with excitation frequencies spanning the 544-nm MLCT band. Self-consistent analysis of the resulting resonance Raman excitation profiles and absorption spectrum using a time-dependent wave packet formalism over two electronic states yields mode-specific vibrational and solvent reorganization energies. Despite the weak electronic coupling between N3 and TiO(2) in N3|TiO(2), adsorption strongly affects the reorganization energies of N3 in the intramolecular MLCT state. Adsorption of N3 onto TiO(2) increases the absolute Raman cross section of each mode by a factor of ca. 1.6 and decreases the vibrational and solvent reorganization energies by factors of 2 and 6, respectively. The excited-state dynamics of N3 adsorbed on the surface of TiO(2) nanoparticles were observed to be independent of the number of N3 molecules adsorbed per TiO(2) nanoparticle. The effect of TiO(2) on the dynamics of the adsorbed N3 is primarily due to both mode-specific vibrational and electronic pure dephasing, with the dominant contribution from the latter process.     

A microchip-based proteolytic digestion system driven by electroosmotic pumping

Microchip-based proteomic analysis requires proteolytic digestion of proteins in microdevices. Enzyme reactors in microdevices, fabricated in glass, silicon, and PDMS substrates, have recently been demonstrated for model protein digestions. The common approach used for these enzyme reactors is employment of a syringe pump(s) to generate hydrodynamic flow, driving the proteins through the reactors. Here we present a novel approach, using electroosmotic flow (EOF) to electrokinetically pump proteins through a proteolytic system. The existence of EOF in the proteolytic system packed with immobilized trypsin gel beads was proven by imaging the movement of a neutral fluorescent marker. Digestions of proteins were subsequently carried out for 12 min, and the tryptic peptides were analyzed independently using capillary electrophoresis (CE) and MALDI-TOF mass spectrometry (MS). The results from CE analysis of the tryptic peptides from the EOF-driven proteolytic system and a conventional water bath digestion were comparable. MALDI-TOF MS was used to identify the parent protein and the tryptic peptides using MS-Fit database searching. The potential utility of the EOF-driven proteolytic system was demonstrated by direct electro-elution of proteins from an acrylamide gel into the proteolytic system, with elution and tryptic digestion achieved in a single step. The EOF-driven proteolytic system, thus, provides a simple way to integrate protein digestion into an electrophoretic micro total analysis system for protein analysis and characterization.     

Dy3+在Ba3La(BO3)3 中的光致发光

研究了Ba3La(BO3)3 基质中Dy3 的光致发光特性; 探讨了RE3 的电荷半径比(z/r)和Ce3 , Dy3 含量对Dy3 发光强度及发光颜色的影响; 分析了Ba3La(BO3)3 中Ce3 对Dy3 发光的敏化作用; 确定了Dy3 的 4F9/2→6H15/2及4F9/2→6H13/2跃迁发射的浓度猝灭机制均为电偶极-电四极相互作用.     

甲基丙烯酸N,N-二甲氨基乙酯与丙烯酰β-环糊精共聚水凝胶的合成及其性能研究

用不同的方法合成了两种结构不同的丙烯酰 β 环糊精酯 (β CD 3 A和 β CD 6 A) ,以此为单体与甲基丙烯酸N ,N 二甲氨基乙酯 (DMAEMA)通过氧化还原自由基引发聚合 ,合成出两类含 β 环糊精结构单元的新型水凝胶 .用核磁共振 ,红外光谱及元素分析对两种单体及共聚物的结构和组成进行了表征 .溶胀实验结果表明 ,两类水凝胶均具有较好的pH、温度及离子强度敏感性 ,且因其交联网络结构不同 ,其溶胀性能有所差异     

Kinetic Monte Carlo simulations of nucleation and growth in electrodeposition

Nucleation and growth during bulk electrodeposition is studied using kinetic Monte Carlo (KMC) simulations. Ion transport in solution is modeled using Brownian dynamics, and the kinetics of nucleation and growth are dependent on the probabilities of metal-on-substrate and metal-on-metal deposition. Using this approach, we make no assumptions about the nucleation rate, island density, or island distribution. The influence of the attachment probabilities and concentration on the time-dependent island density and current transients is reported. Various models have been assessed by recovering the nucleation rate and island density from the current-time transients.     

一种新的滤纸基质固体表面低温荧光(燐光)测定装置

对自行研制的铜制滤纸基质低温荧光（燐光）测定的样品支架，进行了滤纸基质固体表面低温荧光测定的可行性研究。与同类冷冻装置和室温装置比较，本装置用于滤纸基质固体表面低温荧光（燐光）测定具有以下优点；样品的分析周期大大地缩短，由45min缩短为5-6min；装置简单、便宜耐用；操作简便，简化了室温测定时的滤纸干燥程序，应用范围广，方法的重现性好，检样分析结果的相对标准偏差RSD%小于10%，荧光（燐光）分析灵敏度高，检出限低，线性范围宽。     

Pseudolarolides O and P,Two Novel Triterpene Dilactones from Pseudolarix kaempferi

Pseudolarolides O ( 1 ) and P ( 2 ), two novel triterpenoids with a cycloartane‐type framework, were isolated from the seeds of Pseudolarix kaempferi Gord. (Pinaceae). Their structures were elucidated as (16R,23S,25R)‐16,23‐epoxy‐3,4 : 9,10‐disecocycloartan‐1(10),9(11)‐diene‐3(4),26(23)‐diolide ( 1 ), and (9S,16R,23S,25R)‐1,9 : 16,23‐diepoxy‐8,9 : 9,10‐disecocycloartan‐1(29),5(6),10(19)‐triene‐3(4),26(23)‐diolide ( 2 ), respectively, on the basis of spectroscopic techniques and X‐ray‐diffraction studies.     

Chloride substitution of [CpRu(dppf)Cl] with sulfur-containing ligands

The reactions of CpRu(dppf)Cl (1) with the sulfur-containing ligands, thiophenol HSPh, 2-mercaptopyridine C₅H₄N(SH), thiourea SC(NH₂)₂, vinylene trithiocarbonate SCS(CH)₂S and ethylene trithiocarbonate SCS(CH₂)₂S, yielded chloro-substituted derivatives, viz. the mono-ruthenium(II) complexes CpRu(dppf)(SPh) (2), [CpRu(dppf)(SC₅H₄NH)]BPh₄ (3)BPh₄, [CpRu(dppf)(SC(NH₂)₂]PF₆ (4)PF₆, [CpRu(dppf)(SCS(CH)₂S)]Cl (5)Cl and [CpRu(dppf)(SCS(CH₂)₂S)]Cl (6)Cl, respectively. Treatment of 1 with AuCl(SMe₂) in the presence of NH₄PF₆ gave [(CpRu(dppf)(SMe₂)]PF₆ (7)PF₆. The reaction of 1 or 6 with SnCl₂ resulted in cleavage of chloro and dithiocarbonate ligands, respectively, to give CpRu(dppf)SnCl₃ (8). All complexes were spectroscopically characterized and the structures of 2 and cationic complexes 4-7 were determined by single-crystal diffraction analyses.     

A phosphate-based epoxy resin for flame retardance: synthesis, characterization, and cure properties

A phosphorus-containing oligomer, bis(3-hydroxyphenyl) phenyl phosphate (BHPP), was synthesized through the reaction of phenyl dichlorophosphate and 1,3-dihydroxybenzene, and characterized by elemental analysis, Fourier transform IR spectroscopy, and ¹H NMR and ³¹P NMR spectroscopy. Consequently, the phosphate-based epoxy resins with a phosphorus content of 1 and 2 wt % were prepared via the reaction of diglycidyl ether of bisphenol-A with BHPP and bisphenol-A, and were confirmed with Fourier transform IR spectroscopy and gel permeation chromatography. Phenolic melamine, Novolak, and dicyanodiamide were used as curing agents to prepare the thermoset resins with the control and the phosphate-based epoxy resins. Thermal properties and thermal degradation behavior of these thermoset resins were investigated by using differential scanning calorimetry and thermogravimetric analysis. The thermoset resins cured with phenolic melamine exhibited higher glass-transition temperatures than the other cured resins owing to the high rigidity of their molecular chain. Thermogravimetric analysis studies demonstrated that the decomposition temperatures of the thermoset resins cured with Novolak were higher than those of the others. A synergistic effect from the combination of the phosphate-based epoxy resin and the nitrogen-containing curing agent can result in a great improvement of the flame retardance for their thermoset resins.