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The insertion reactions of the p-complex structure (A) of silylenoid H2SiLiF into C–X bonds of CH3XH
n−1 (X = F, Cl, Br, O, N; n = 1, 1, 1, 2, 3) have been studied using ab initio and DFT methods. The results indicate that the insertions proceed in a
concerted manner, forming H2SiXH
n−1CH3 and LiF. The order of reactivity by A insertion indicates the reaction barriers increase for the same-row element X from right to left in the periodic table, whereas
change very little for the same-family element X. The insertions of A and the three-membered-ring structure of H2SiLiF are similar. Both structures may participate in insertion reactions. 相似文献
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The structures of pentacoordinate silylenoid PhCH2(NH2)CH3SiLiF were studied by density functional theory at the B3LYP/6-31G(d) level. Three equilibrium structures, the three-membered
ring (1), the p-complex (2), and the σ-complex (3) structures, were located. Their energies are in the order of 2 > 1 > 3 both in vacuum and in THF. To exploit the stability of PhCH2(NH2)CH3SiLiF, the insertion reactions of 1 and PhCH2(NH2)CH3Si into C–F have been investigated, respectively. The results show that the insertion of PhCH2(NH2)CH3Si is more favorable. To probe the influence of amine-coordination to the stability of PhCH2(NH2)CH3SiLiF, the insertion reaction of PhCH3CH3SiLiF was also investigated. The calculations indicate that the insertion of PhCH3CH3SiLiF is more favorable than that of 1. So the N atom plays an important role on the stability of silylenoid PhCH2(NH2)CH3SiLiF. 相似文献
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Lei?Jiao Zonggang?Mu Luyang?Miao Wenwen?Du Qin?Wei He?LiEmail author 《Mikrochimica acta》2017,184(2):423-429
A dual enhancing strategy has been employed to develop a sandwich type of electrochemical immunoassay for the prostate specific antigen (PSA). The signal is enhanced by using Pt-Cu hierarchical trigonal bipyramid nanoframes (HTBNFs) and a composite consisting of Fe3O4 nanoparticles and reduced graphene oxide in polydopamine that serve to capture the primary antibody (Ab1). This nanocomposite shows better electrical conductivity than Fe3O4 and reduced graphene oxide (RGO), respectively, alone. The Pt-Cu HTBNFs were used to label the secondary antibody (Ab2) and act as tags for signal amplification by virtue of their outstanding electrochemical reduction activity towards H2O2. At a working potential of +0.1 V (vs. SCE), the interference by dissolved oxygen can be avoided. This immunoassay is highly sensitive, with a linear range that extends from 0.1 pg?mL?1 to 5 ng?mL?1 and an ultralow detection limit of 0.03 pg?mL?1. 相似文献
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铸铁表面化学沉积Ni—P镀层和Ni—P—SiC复合镀层的耐磨性研究 总被引:2,自引:0,他引:2
作者利用化学沉积法在低合金铸铁表面分别制取了Ni-P镀层和Ni-P-SiC复合镀层,并就两者的耐磨性与铸铁、磷化处理表面及Cr镀层的进行了对比试验研究。结果表明,Ni-P镀层的耐磨性比铸铁及磷化处理的好,但比Cr镀层和Ni-P-SiC复合镀层的差,并以后者的为最佳。 相似文献
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