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61.
Pseudo-stationary phases for electrokinetic chromatography were prepared by the alkylation of starburst dendrimers (SBDs). The SBD-supported pseudo-stationary phase with dodecyl groups showed higher efficiency than short-akyl derivatives, and maintained the hydrophobic property inthe presence of methanol. The dodecyl-modified SBD provided wide migration time windows ar high methanol content to effect the separation of sixteen aromatic hydrocarbons, the priority pollutants designated by EPA, in 65% methanol. The selectivity of polymer-supported pseudo-stationary phase can be varied simply by changing the length of the alkyl groups. The dodecyl SBD showed relatively similar selectivity as sodium dodecyl culfate micelle, whereas short alkyl derivatives showed preference towards rigid and planar compounds based on the rigid and planar compounds based on the rigid polymer backbones. The selectivity of SBD-supported pseudo-stationary phases was dominated by the chain length of the alkyl groups, with the minor effect of the structure of the core and the generation of SBD where alkyl groups were attached.  相似文献   
62.
The microstructure of the polymer formed by the hydrosilation of styrene with poly(hydrogenmethylsiloxane) was studied by 1H- and 13C-NMR spectra. Two modes of addition in hydrosilation were found to occur randomly without the influence of the adjacent monomer unit by statistical analysis of sequence distribution of 29Si-NMR spectrum.  相似文献   
63.
14C variations of atmospheric CO2 as well as carbonaceous fraction of living materials, such as collagen from tooth and bone, tissue, skin, hair, nail, etc., of modern humans are influenced by 14C produced artificially by nuclear bomb tests in the atmosphere from late 1950s to early 1960s. By careful investigation of 14C concentration of tree rings and human body samples formed in this time intervals, we can establish a relationship of their 14C concentrations with calendar year. By applying this relation to a sample whose 14C concentration can be measured, we can estimate the formation age of the sample. In addition, sources of the chemicals that were used in some criminal cases can be possibly identified, by their carbon isotope ratios (13C/12C and 14C/12C). This method of age determination has been applied to a forensic study, i.e., two criminal cases of murder. For each case, by comparing the measured 14C abundances of several pieces of hair and one tooth (the third molar) from the body with the annual change on concentrations of bomb-produced 14C, the time of death of the body and the age of the victim were estimated. The estimated values were consistent with the real ones that were revealed by the confession of the real murderers.  相似文献   
64.
The reactions of F-2-methyl-2-pentene (1) with several ortho- difunctional benzenes afforded eight- and nine-membered benzoheterocyclic compounds carrying perfluoroalkyl groups. Salicylic acid, salicylaldehyde, and their methyl or chloro derivatives reacted in triethylamine-acetonitrile system giving perfluoroalkylated 2H,6H-1,5-benzodioxocin-2,6-dione (8) and 4H,6H-1,5-benzodioxocin (9) compounds respectively, while phthalyl alcohol and o-hydroxyphenethyl alcohol in triethylamine-diethyl ether system gave perfluoroalkylated 1H,3H,7H-2,6- and 4H,6H,7H-1,5-benzodioxonin compounds, (10) and (11). o-Aminobenzyl alcohol and (1) in diethyl ether afforded a perfluoroalkylated benzoxazocinobenzoxazocinone compound (15).  相似文献   
65.
66.
trans‐Di­aqua­bis­(iso­quinoline‐1‐carboxyl­ato‐κ2N,O)­cobalt(II) dihydrate, [Co(C10H6NO2)2(H2O)2]·2H2O, and trans‐di­aqua­bis­(iso­quinoline‐1‐carboxyl­ato‐κ2N,O)­nickel(II) dihydrate, [Ni(C10H6NO2)2(H2O)2]·2H2O, contain the same isoquinoline ligand, with both metal atoms residing on a centre of symmetry and having the same distorted octahedral coordination. In the former complex, the Co—O(water) bond length in the axial direction is 2.167 (2) Å, which is longer than the Co—O(carboxylate) and Co—N bond lengths in the equatorial plane [2.055 (2) and 2.096 (2) Å, respectively]. In the latter complex, the corresponding bond lengths for Ni—O(water), Ni—O(carboxylate) and Ni—N are 2.127 (2), 2.036 (2) and 2.039 (3) Å, respectively. Both crystals are stabilized by similar stacking interactions of the ligand, and also by hydrogen bonds between the hydrate and coordinated water molecules.  相似文献   
67.
Photooxygenation reaction of an unsaturated fatty acid ester, methyl linoleate (methyl 9- cis. 12- cis -octadecadienoate, ML-H), sensitized by porphyrins and several types of dyes has been studied in aqueous emulsion and acetonitrile solution under air at 40°C. The oxygen (O2) uptake proceeded slowly in the absence of sensitizers upon irradiation of an aqueous emulsion and an acetonitrile solution of ML-H (20 m M ) at ℷex > 290 nm (11.4 and 6.1 μmol h-1, respectively). The rate of O2 uptake was enhanced by a catalytic amount (0.1 m M ) of porphyrins and dyes; hematoporphyrin (HP), zinc tetrakis(N-methyl-4-pyridiniumyi)porphyrin (ZnTMPyP), methylene blue (MB), rose bengal (RB), acridine orange (AO), and acriflavine (AF). In both systems, the sensitized photooxidation of ML-H by O2 proceeded equimolarly to produce isomeric mixture of C9 and C13 hydroperoxides having the trans,cis and trans,trans conjugated diene configurations, independent of the types of the sensitizers used. The yield ratio of trans,trans/ trans,cis products in the MB-sensitized photooxygenation in acetonitrile and aqueous emulsion were almost equal (0.32 and 0.35. respectively). The sensitizing activity of the sensitizers, as measured by the quantum yield of O2 uptake, increased in the order: MB (≃ 0) < ZnTMPyP < RB < HP < AF < AO in the aqueous emulsion and AO < AF < HP < RB = MB in the acetonitrile solution. The order in homogeneous acetonitrile solution was interpreted by the sensitizing ability of the dyes to produce singlet oxygen, while that in heterogeneous aqueous emulsion was correlated to the lipophilicity of dyes as well as the singlet-oxygen-producing ability.  相似文献   
68.
A series of sulfido-bridged tungsten-ruthenium dinuclear complexes Cp*W(mu-S)(3)RuX(PPh(3))(2) (4a; X = Cl, 4b; X = H), Cp*W(O)(mu-S)(2)RuX(PPh(3))(2) (5a; X = Cl, 5b; X = H), and Cp*W(NPh)(mu-S)(2)RuX(PPh(3))(2) (6a; X = Cl, 6b; X = H) have been synthesized by the reactions of (PPh(4))[Cp*W(S)(3)] (1), (PPh(4))[Cp*W(O)(S)(2)] (2), and (PPh(4))[Cp*W(NPh)(S)(2)] (3), with RuClX(PPh(3))(3) (X = Cl, H). The heterolytic cleavage of H(2) was found to proceed at room temperature upon treating 5a and 6a with NaBAr(F)(4) (Ar(F) = 3, 5-C(6)H(3)(CF(3))(2)) under atmospheric pressure of H(2), which gave rise to [Cp*W(OH)(mu-S)(2)RuH(PPh(3))(2)](BAr(F)(4)) (7a) and [Cp*W(NHPh)(mu-S)(2)RuH(PPh(3))(2)](BAr(F)(4)) (8), respectively. When Cp*W(O)(mu-S)(2)Ru(PPh(3))(2)H (5b) was treated with a Br?nstead acid, [H(OEt(2))(2)](BAr(F)(4)) or HOTf, protonation occurred exclusively at the terminal oxide to give [Cp*W(OH)(mu-S)(2)RuH(PPh(3))(2)](X) (7a; X = BAr(F)(4), 7b; X = OTf), while the hydride remained intact. The analogous reaction of Cp+W(mu-S)(3)Ru(PPh(3))(2)H (4b) led to immediate evolution of H(2). Selective deprotonation of the hydroxyl group of 7a or 7b was induced by NEt(3) and 4b, generating Cp*W(O)(mu-S)(2)Ru(PPh(3))(2)H (5b). Evolution of H(2) was also observed for the reactions of 7a or 7b with CH(3)CN to give [Cp*W(O)(mu-S)(2)Ru(CH(3)CN)(PPh(3))(2)](X) (11a; X = BAr(F)(4), 11b; X = OTf). We examined the H/D exchange reactions of 4b, 5b, and 7a with D(2) and CH(3)OD, and found that facile H/D scrambling over the W-OH and Ru-H sites occurred for 7a. Based on these experimental results, the mechanism of the heterolytic H(2) activation and the reverse H(2) evolution reactions are discussed.  相似文献   
69.
The crystal structures of the series of four ternary complexes, [Pd(phen)(2,6-PDCA)].4H(2)O (1) (phen=1,10-phenanthroline; 2,6-PDCA=2,6-pyridinedicarboxylic acid), [Pd(bpy)(2,3-PDCA)].3H(2)O (2) (bpy=2,2'-bipyridineand; 2,3-PDCA=2,3-pyridinedicarboxylic acid) and [Pd(phen)(PHT)].2.5H(2)O (3) (PHT=o-phthalic acid ) and [Pd(bpy)(PHT)].1.5H(2)O (4), are determined and the coordination modes of palladium(II) ternary complexes are characterized. All complexes take the mononuclear Pd(II) complexes, in which central Pd(II) atom of each complex has a similar distorted square-planar four coordination geometry. In all complexes, the aromatic heterocyclic compounds, phen and bpy, behave as a bidentate N, N' ligand. In the complex 1 and 2, 2,6-PDCA and 2,3-PDCA behave as a bidentate N, O ligand, and in complex 3 and 4, PHT behaves as a bidentate O, O' ligand.  相似文献   
70.
Charge-discharge capacity and cyclicity of lithium ion battery (LIB) was evaluated in which 15Li2O·10Fe2O3·xSnO2·5P2O5·(70–x)V2O5 glass (x?=?0 and 20 in mol%, abbreviated as xLFSPV) was used as a cathode. A local structure of xLFSPV glass before and after charging was investigated by 57Fe- and 119Sn-Mössbauer spectroscopies. 57Fe-Mössbauer spectrum of xLFSPV glass with ‘x’ of 20 was composed of a doublet with isomer shift (δ) of 0.35±0.02 mm s???1 and quadrupole splitting (Δ) of 0.88±0.03 mm s???1 due to distorted FeIIIO4 tetrahedra. 119Sn-Mössbauer spectrum of this glass consisted of a doublet with δ of 0.08±0.01 and Δ of 0.52±0.01 mms???1 due to distorted SnVIO6 octahedra. After discharging the battery from 4.5 to 1.0 V, larger δ of 0.40±0.03 mm s???1 and Δ of 0.94±0.04 mm s???1 were obtained, indicating that both iconicity of Fe-O bonds and local distortion of FeIIIO4 tetrahedra were increased. On the contrary, identical δ of 0.09±0.01 mm s???1 and Δ of 0.50±0.01 mm s???1 were observed in the 119Sn-Mössbauer spectrum of 20LFSPV glass after the discharge, indicating that chemical environment of SnIVO6 octahedra was not affected after the discharge. Charge-discharge curve of LIB containing 20LFSPV glass as a cathode active material recorded under the current density of 8.3 mA g???1 (0.011 mA cm???2) between 1.0 and 4.5 V showed a large initial charge capacity of 431.1 mAh g???1 and discharge capacity of 382.3 mAh g???1, respectively. These results indicate that 20LFSPV glass could be a new cathode active material for LIB.  相似文献   
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