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An efficient Ag(I)-catalyzed borylation method of terminal alkynes is reported. The obtained borylated alkynes are shown to engage in C–Br, C–CN, C–N, and C–C bond formation with various reaction partners. Meanwhile the Ag(I) catalyst could be regenerated in the presence of PPh3 and BF3. 相似文献
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使用Galerkin有限元法研究了多维非定常中子迁移方程,证明了Galerkin有限元法近似解的收敛性和广义解的存在性. 相似文献
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《Spectrochimica Acta Part B: Atomic Spectroscopy》1986,41(4):361-376
Physical parameters and analytical performance are determined for an analytical ICP operated at 148 MHz, a frequency nearly three times higher than any previously reported. The iron(I) excitation temperatures are approximately 1.5 times lower and the electron densities are five times lower than at 27 MHz. The consequences of these changes are lower analyte and background continuum emission intensities, such that the signal to background ratios are decreased at the higher frequency. Freedom from interferences and working curve linearity are unaffected while ease of sample introduction is improved. A shift towards atomic emission indicates a deviation farther from LTE at 148 MHz. These effects are attributed to the decrease in skin depth with increasing frequency. 相似文献
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The first purpose of this paper is to study the properties on some q-shift difference differential polynomials of meromorphic functions,some theorems about the zeros of some q-shift difference-differential polynomials with more general forms are obtained.The second purpose of this paper is to investigate the properties on the Nevanlinna deficiencies for q-shift difference differential monomials of meromorphic functions,we obtain some relations amongδ(∞,f),δ(∞,f′),δ(∞,f(z)nf(qz+c)mf′(z)),δ(∞,f(qz+c);f′(z))andδ(∞,f(z)nf(qz+c)m). 相似文献
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在氩气保护下,以邻位-碳硼烷、正丁基锂、硒粉和CpCo(CO)I2为起始原料,合成、分离得到配合物CpCo(Se2C2B10H10)(1)、(CpCo)2(Se2C2B10H10)(2)和(CpCo)4(μ3-Se)4Co2(μ3-Se2C2B10H10)4Co·CH2Cl2(3),并用元素分析、质谱、IR、1H NMR及X-射线单晶衍射对配合物(3)进行了表征。晶体属正交晶系,空间群P212121,其晶胞参数为:a=1.30720(13)nm,b=1.39137(11)nm,c=3.88533(15)nm,β=90°,Z=4,V=7.0666(9)nm3,μ=7.890mm-1,Dc=2.138g·cm-3,F(000)=4268,R1=0.0543,wR2=0.1363。配合物中4个(Se2C2B10H10)2-配体和4个单硒基团形成了1个Co7Se12核。 相似文献
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在DDQ/PPh3作用下,以2-异丙基苯甲酸或水杨酸为原料,在温和条件下以较高的收率合成、分离得到两个化合物(2)和(3)。化合物(2)和(3)与苯胺在氯仿中加热回流可分别转化为酰胺类化合物(4)和(5)。所有化合物通过元素分析、质谱、核磁共振进行了表征,并解析了化合物(2)和(3)的X-衍射单晶结构。化合物1,2-二(2-异丙基苯甲酸)-2,3-二氰-5,6-二氯苯(2)晶体属单斜晶系,空间群P21/c,其晶胞参数为:a=1.2875(3)nm,b=1.5186(2)nm,c=1.5726(3)nm,β=122.23(3)°,V=2.6010(1)nm3,Dc=1.331g·cm-3,Z=4,F(000)=1080,R1=0.0572,wR2=0.1260;化合物1,2-二(2-羟基苯甲酸)-2,3-二氰-5,6-二氯苯(3)晶体属三斜晶系,空间群P1,其晶胞参数为:a=0.87776(16)nm,b=1.13111(15)nm,c=1.18639(17)nm,α=69.290(2)°,β=89.409(3)°,γ=67.878(2)°,V=1.0104(3)nm3,Dc=1.542g·cm-3,Z=2,F(000)=476,R1=0.0383,wR2=0.0931。强π-π堆积作用和分子间氢键将化合物(2)和(3)组装成稳定的三维结构。 相似文献
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半夹芯16e化合物CpCoS2C2B10H10(Cp:cyclopentadienyl)(1)与2-呋喃炔酮在物质的量比为1:1.5时反应分离得到1个顺磁性化合物CpCoS2C2B10H9(C12H10O2)(2)。在化合物2的合成过程中,一分子1中的Cp环与另一分子1中的B(3)/B(6)位连接;同时,该Cp环与1个2-呋喃炔酮分子发生Diels-Alder反应,生成1个双环[2.2.1]-2-庚烯基结构单元。此外,呋喃炔酮分子中的末端炔基碳原子与原料1中的1个硫原子相连,从而使得产物2中的钴中心离子是个17e中心。化合物2用红外、核磁、元素分析,质谱和单晶X-射线衍射分析等方法进行了表征。晶体属三斜晶系,空间群P1,晶胞参数:a=0.96657(11)nm,b=1.54423(15)nm,c=1.75650(18)nm,α=114.0800(10)°,β=105.433(2)°,γ=98.6390(10)°。 相似文献