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1.
Complexes of the Alkali Metal Tetraphenylborates with Macrocyclic Crown Ethers Alkali metal tetraphenylborates, MB(C6H5)4 (M = Li to Cs), react in tetrahydrofuran with macrocyclic crown ethers to give complexes of the general formula MB(C6H5)4(crown)m(THF)n. Suitable single crystals for X‐ray structure analysis were grown from a solvent mixture of tetrahydrofuran and n‐hexane. The salt like complexes [Li(12‐crown‐4)(thf)][B(C6H5)4] ( 1 ), [Na(15‐crown‐5)(thf)][B(C6H5)4] ( 2 ), and [Cs(18‐crown‐6)2][B(C6H5)4] · THF ( 6 ), the mononuclear molecular complexes [KB(C6H5)4(18‐crown‐6)(thf)] ( 3 ), [RbB(C6H5)4(18‐crown‐6)] ( 4 ), and [CsB(C6H5)4(18‐crown‐6)] · THF ( 5 ), and the compound [CsB(C6H5)4(18‐crown‐6)]2[Cs(18‐crown‐6)2][B(C6H5)4] ( 7 ), which contains a binuclear molecule ([CsB(C6H5)4(18‐crown‐6)]2) beside a [Cs(18‐crown‐6)2]+ cation and a [B(C6H5)4]? anion, are described. All compounds are charactarized by infrared spectra, elemental analysis, NMR‐spectroscopy, and X‐ray single crystal structure analysis.  相似文献   
2.
研究了以熔融萘作为萃取剂,以4,7 二苯基 1,10 菲口罗啉作为显色剂,测定天然水中微量铁的分光光度法。在pH4的条件下,铁(Ⅱ)与4,7 二苯基 1,10 菲口罗啉和四苯硼酸盐能够形成红色三元络合物。在熔融萘存在下,此络合物可以迅速萃入熔融萘。将含有络合物的萘冷却、固化、分离,配制成25mL丙酮溶液,对其进行分光光度分析。实验表明,该络合物最大吸收波长为534nm,摩尔吸光系数和桑德尔灵敏度分别为2×104L·mol-1·cm-1和0.0025μg/cm2,铁(Ⅱ)的质量浓度在0~2 0μg/mL的范围内符合比耳定律。大多数常见离子不干扰测定。已应用于天然水中微量铁的测定。  相似文献   
3.
An efficient and general method for the synthesis of alkyl squarates is presented. This involves the reactions of squaric acid with the desired alcohol in the presence of an orthoformate. This was applicable for the synthesis of dimethyl-, diethyl-, diisopropyl, di-n-butyl and di-t-butyl squarates in yields ranging from 77–97%. It is a convenient and safe method that can be accomplished on a multigram scale.  相似文献   
4.
Air-stable and crystalline N-acyl DBN tetraphenylborate salts have been shown to be effective O-acylating agents, reacting with both primary and secondary alcohols to give the corresponding esters in good yields. In the case of diols, the N-acyl DBN·BPh4 salts have been shown to acylate regioselectively the primary alcohol functionality in the presence of a secondary alcohol. The DBN hydrotetraphenylborate side product can be readily removed by filtration, providing the ester products without the need for further purification.  相似文献   
5.
A method is described for the indirect determination of the mobility of the electroosmotic flow (EOF), which can be carried out within a few minutes even for very low mobilities. It is independent of the direction of the EOF. It is based on the comparison of the measured mobilities of two oppositely charged reference ions (tetraphenylphosphonium and tetraphenylborate) with given mobilities in different organic solvents (methanol, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, propylene carbonate) at ionic strengths between 5 and 50 mM. The method is based on the sequential movement of the reference ions in a three-step process: first by a laminar flow to a certain position in the separation capillary, followed by electromigration due to application of voltage, and pressurised migration towards the detector. In this way the total mobilities of the reference ions can be determined from their residence times, and the difference to their known actual mobilities gives the mobility of the EOF. The method avoids misinterpretations caused by system- and eigen-peaks, which often bias the results especially when a conductivity detector is used. The method is suitable for all solvents, and is an advantage especially for organic and mixed aqueous–organic background electrolytes with high UV absorbance.  相似文献   
6.
Treating the complexes [Rh(TFA)(PPh3)2], [Rh(HFA)(PPh3)2], and [Rh(TFA)(Cod)] (TFA - trifluoroacetylacetonate, HFA - hexafluoroacetylacetonate, Cod - 1,5 cyclooctadiene) with an excess of NaBPh4 in acetonitrile yields the rhodium(I) complexes with coordinated [BPh4] anion, [Rh(PPh3)2(π-PhBPh3)] · 2MeCN (I) and [Rh(Cod)(π-PhBPh3)] (II). The reactions present a new example of β-diketonate ligand replacement. The 1H, 31P, and 11B NMR spectra of I and II are discussed. [Rh(PPh3)2(π-PhBPh3)] has been characterized by single crystal X-ray analysis.  相似文献   
7.
碘解磷定的ICP-AES测定   总被引:5,自引:2,他引:3  
王伟 《光谱实验室》2002,19(2):264-266
利用等离子体发射光谱法间接碘解磷。在pH5.0的溶液中,当四苯硼钠过量时可完全沉淀碘解磷定,测定滤液中剩余的四苯硼钠,使可计算得到碘解磷定的含量。该方法简单、快速,回收率在97%-101%之间,相对标准偏差小于2.1%。  相似文献   
8.
本文提出了以四苯钠为沉淀剂,ICP-AES间接测定药物成份奎宁的新方法。对影响沉淀反应的条件进行了详细考察和优化,在选择好的实验条件下,本法的检出限为0.07μg/mL,RSD为4%。实验表明,较大量的基体(碱土金属Ca和Mg)存在对测定结果无明显影响,但可与试剂反应的K+、产生正干扰。本法已用于复方奎宁注射液中有效药物成份的测定,分析结果满意。  相似文献   
9.
原子吸收光谱法间接测定硫酸阿托品   总被引:2,自引:0,他引:2  
张雨青  王伟 《光谱实验室》2002,19(5):665-667
研究了原子吸收光谱法间接测定硫酸阿托品的方法。在pH为5.0的溶液中,当四苯硼钠过量时可完全沉淀硫酸阿托品,在滤液中加入过量的氯化钾沉淀剩余的四苯硼钠,再测定过量的钾可以计算得到硫酸阿托品的含量。方法简单、快速,回收率在97%-101%之间,相对标准偏差为1.1%。  相似文献   
10.
《Electroanalysis》2006,18(5):440-448
We report the combination of the charge repelling property of tetraphenyl‐borate (TPB) anion and the electrooxidation catalytic effect of cobalt(II) tetrakisphenylporphyrin (CoTPP) embedded in a sol gel ceramic film to develop a modified glassy carbon electrode (CoTPP‐TPB‐SGGCE) for the simultaneous determination of dopamine (DA) and uric acid (UA). The optimized CoTPP‐TPB‐SGGCE shows excellent sensitivity and selectivity for the DA and UA analysis. As high as 2000 fold acceptable tolerance of ascorbic acid (AA) for the determination of trace DA and UA is reached. In the presence of 0.10 mM AA, the linear concentration range for DA is from 6.0×10?8 to 2.5×10?5 M, and the detection limit is 2.0×10?8 M. For UA, the linear concentration range is from 1.0×10?7 to 3.5×10?5 M, and the detection limit is 7.0×10?8 M. Our study has also demonstrated that the novel CoTPP‐TPB‐SGGCE shows high stability and reliability. For 6.00 μM DA and UA, a total of 12 measurements were taken in one week, and the relative standard deviation is 2.05% and 2.68% respectively. No obvious shift of peak current and peak potential is observed over a three‐month lifetime test. The response of the sensor is very quick and response time is approximately 1 s. Satisfactory results are also achieved when the CoTPP‐TPB‐SGGCEs being used to detect the DA and UA in human urine samples.  相似文献   
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