共查询到14条相似文献,搜索用时 15 毫秒
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本文采用原位核磁共振方法检测不同碱度硅铝酸钠溶液中27Al的信号, 在比较了文献实验结果的基础上, 明确了体系中的不同铝物种的化学位移, 进一步提出了硅铝酸钠溶液中的硅铝物种的归属. 相似文献
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New model compound 1H,1′H-Bis(benz-Δ^4-imidazoline)2,2′-spiro-titanium dichloride was prepared and the structure of the compound was determined by 1R,MS and elementary analysis. 相似文献
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研究了用带电导检测器的离子色谱对米酒中F-、Cl-和SO24-进行分离测定的方法.在Dionex HPIC-AS3分离柱上用2.8mmol@L-1NaHCO3-2.2mmol@L-1Na2CO3作流动相进行洗脱,被测组分得到满意的分离,方法简便快速.F-、Cl-和SP24-线性范围分别为0.1~10、0.1~16和0.5~80mg@L~,检出限分别为0.1、0.1和0.5mg@L-1.该法也适用NO-3和NO-2测定. 相似文献
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Ismail等人于1968年以水杨酰苯胺与二甲基二氯硅烷按摩尔比1:1新的有机硅化合物,通过测定该化合物的IR谱与2:1产物的IR谱图进行比较,指认其结构为亚胺式(Ⅱ),否定酮式(Ⅰ)。 相似文献
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3—甲氧基—甲亚胺H光度法测定植物中硼的研究及应用 总被引:8,自引:1,他引:7
研究了3-甲氧基-甲亚胺H与硼的显色反应。在乙酸-乙酸铵缓冲溶液中。硼与3-甲氧基-甲亚胺H形成1:2的黄色配合物,最大吸收在420nm波长处,摩尔吸尤系数为7.19×10~3,Sandell灵敏度为0.0015/μg·cm~(-2)。当硼含量在0~35μg/25ml范围内符合比耳定律,应用于植物中硼的测定获得满意的结果。 相似文献
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用密度泛函UB3LYP/6-311++G**方法计算研究了气相中CrO2^+(2^A1/4^A")活化甲烷C—H键的微观机理,找到了四条反应通道.对其中涉及的两态反应(TSR)进行了分析,并对影响反应机理和反应速率的势能面交叉现象(potential energy surfaces crossing)进行了详细讨论,进而运用Hammond假设和Yoshizawa等的内禀坐标单点垂直激发计算的方法找出了一系列势能面交叉点[crossing points(CPs)],并作了相应的讨论.进一步用碎片分子轨道理论[fragment molecular orbital(FMO)]对TS1中的轨道相互作用进行了分析,解释了CrO2^+活化甲烷C—H键的机理. 相似文献
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1 INTRODUCTIONTransition metal clusters have been attracting intensive attention largely because they are suggested as active catalysts in a variety of homogeneous catalyzed reactions. However, no unequivocal proof exists that metal clusters themselves serve as the true catalysts among the catalytic process. In many cases it is known that fragments of the original clusters are the actual catalytic species. The unambiguous proof would be the use of a rigid chiral cluster to catalyze an asy… 相似文献
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The reaction of the rifle cyclic complex (1) with sodium amalgam in THF resulted in the expected cleavage of the Fe-Fe bond to afford his-sodium salt ( Me2SiSiMe2 ) [η^5-C5H4Fe(CO)2]2 (4). The latter was not isolated and was used directly to react with MeI, PhCH2Cl, CH3C(O)Cl, PhC(O)Cl,Cy3SnCl (Cy= cyclohexyl) or Ph3SnCl to afford corresponding ring-opened derivatives (Me2SiSiMe2) [η^5-C5H4Fe(CO)2]2 [5, R=Me; 6, R=PhCH2; 7, R=CH3C(O); 8, R=PhC(O); 9, R = Cy3Sn or 10, R = Ph3Sn ]. The crystal and molecular structures of 10 were determined by X-ray diffraction analysis. The molecule took the desired ant/ conformation around the Si-Si bond. The length of the Si--Si bond is 0.2343(3)nm, which is essentially identical to that in the cyclic structure of 1[0.2346(4) tun]. This result unambiguously demonstrates that the Si--Si bond in the cyclic structure of 1 is not subject to obvious strain. 相似文献