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991.
An improved method for the deprotection of benzyl ethers using a catalytic amount of Co(2)(CO)(8) in the presence of Me(2)PhSiH and CO (1 atm) is described. The deprotection reaction is compatible with double bond or sulfur-containing substrates. The method also tolerates other functional groups, such as Ac, Piv, and Bz, and shows potential selectivity in perbenzylated monosaccharides. 相似文献
992.
The reactions of C(2)H(4) with H(2) on neutral vanadium sulfide clusters in a fast flow reactor are investigated by time-of-flight mass spectrometry employing 118 nm (10.5 eV) single photon ionization. The experimental products of these reactions are V(m)S(n)C(2)H(x) (m=1, n=1-3; m=2, n=1-5, and x=4-6). Observation of these products indicates that these V(m)S(n) clusters have high catalytic activity for hydrogenation reactions of C(2)H(4). Density functional theory calculations at the BPW91/TZVP level are carried out to explore the geometric and electronic structures of the V(m)S(n) clusters and to determine reaction intermediates and transition states, as well as reaction mechanisms. All reactions are estimated as overall barrierless or with only a small barrier (0.1 eV), and are thermodynamically favorable processes at room temperature. The ethylene molecule is predicted to connect with active V atoms through its π-orbital or form a σ-bond with active V atoms of catalytic V(m)S(n) clusters. The S atoms bonding with active V atoms play an important role in the dissociation of the H(2) molecule; H atoms transfer to the C(2)H(4) (one after another) following breaking of the H-H bond. A catalytic cycle for C(2)H(4) hydrogenation reactions on a vanadium sulfide catalyst surface is suggested based on our experimental and theoretical investigations. 相似文献
993.
Photodissociation dynamics of salicylic acid (SA) in the gas phase at different photolysis wavelengths (266, 315-317 nm) is investigated by probing the nascent OH photoproduct employing the single-photon laser-induced fluorescence (LIF) technique. At all the photolysis wavelengths it is found that the nascent OH radicals are produced mostly in a vibrationally ground state (υ' = 0) and have similar rotational state distributions. The two spin-orbit and Λ-doublet states of the OH fragment formed in the dissociation are measured to have a nonstatistical distribution at each photolysis wavelength. The LIF signal of the OH could be observed upon photolysis at 317 nm but not at 317.5 nm. The threshold of OH formation from SA photodissociation is estimated to be 98.2 ± 0.9 kcal/mol. The effect of the phenolic OH group on the dissociation of SA is discussed. 相似文献
994.
Shen M Zhang L Lee KM Vermeulen R Hosgood HD Li G Yin S Rothman N Chanock S Smith MT Lan Q 《Experimental & molecular medicine》2011,43(6):374-378
Benzene, a recognized hematotoxicant and carcinogen, can damage the human immune system. We studied the association between single nucleotide polymorphisms (SNPs) in genes involved in innate immunity and benzene hematotoxicity in a cross-sectional study of workers exposed to benzene (250 workers and 140 controls). A total of 1,236 tag SNPs in 149 gene regions of six pathways were included in the analysis. Six gene regions were significant for their association with white blood cell (WBC) counts (MBP, VCAM1, ALOX5, MPO, RAC2, and CRP) based on gene-region (P<0.05) and SNP analyses (FDR<0.05). VCAM1 rs3176867, ALOX5 rs7099684, and MPO rs2071409 were the three most significant SNPs. They showed similar effects on WBC subtypes, especially granulocytes, lymphocytes, and monocytes. A 3-SNP block in ALOXE3 (rs7215658, rs9892383, and rs3027208) showed a global association (omnibus P = 0.0008) with WBCs even though the three SNPs were not significant individually. Our study suggests that polymorphisms in innate immunity genes may play a role in benzene-induced hematotoxicity; however, independent replication is necessary. 相似文献
995.
Tetrahedron-structured DNA (ts-DNA) in combination with a functionalized oligonucleotide was used to develop a "turn-on" biosensor for Hg(2+) ions. The ts-DNA provided an improved sensitivity and was used to block the active sites. 相似文献
996.
Ding S Luan D Boey FY Chen JS Lou XW 《Chemical communications (Cambridge, England)》2011,47(25):7155-7157
We demonstrate a new hydrothermal method to directly grow SnO(2) nanosheets on a graphene oxide support that is subsequently reduced to graphene. This unique SnO(2)/graphene hybrid structure exhibits enhanced lithium storage properties with high reversible capacities and good cycling performance. 相似文献
997.
Yin M Huang Y Liang L Liao J Liu C Xing W 《Chemical communications (Cambridge, England)》2011,47(28):8172-8174
CO poisoning during methanol electrooxidation was investigated on PtAu alloys with different surface compositions. Results show that the CO formation can be reduced gradually with increasing surface Au fractions in PtAu alloys and CO poisoning can be almost eliminated by adjusting to a proper surface Au fraction. 相似文献
998.
Cheng W Chen Y Yan F Ding L Ding S Ju H Yin Y 《Chemical communications (Cambridge, England)》2011,47(10):2877-2879
A simple scanometric strategy was developed for ultrasensitive assay of matrix metalloproteinases based on their discriminatory and proteolytic activity by integrating a newly designed peptide-gold nanoparticle probe, a nitrilotriacetic acid modified chip and silver signal amplification. 相似文献
999.
Guo C Yin S Huang L Yang L Sato T 《Chemical communications (Cambridge, England)》2011,47(31):8853-8855
Cs(0.32)WO(3) nanorods, synthesized by a designed water controlled-release process, exhibited strong absorption of light in a wide waveband of 800-15,000 nm, quick conversion of photo-energy to local heat and excellent heat rays cutoff character. 相似文献
1000.
Li B Cao H Shao J Zheng H Lu Y Yin J Qu M 《Chemical communications (Cambridge, England)》2011,47(11):3159-3161
Incorporation of reduced graphene oxide into β-Ni(OH)(2) presents high performances with specific discharge capacity of 283 mA hg(-1) after 50 cycles in Ni-MH batteries, and 507 mA hg(-1) after 30 cycles in Li ion batteries. 相似文献