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1.
报道了显色剂1-(4-硝基苯基)-3-(2-吡嗪)-三氮烯化合物的合成及其与镉(Ⅱ)的显色反应。在非离子表面活性剂Triton X-100存在下,pH 10.5的Na2B4O7-NaOH的缓冲介质中,该试剂能与镉(Ⅱ)与发生显色反应,形成摩尔比为4∶1的黄棕色配合物,配合物在波长453 nm处有最大吸收峰,表观摩尔吸光系数ε为6.90×104L.mol-1.cm-1,镉(Ⅱ)质量浓度在0~0.56μg/mL范围内遵守比尔定律。用拟定方法测不同废水中的镉(Ⅱ)。  相似文献   

2.
报道了新显色剂1-偶氮苯-3-(5,6-二甲基-1,2,4-三氮唑)-三氮烯(ABDMTT)的合成及其与镉的显色反应。在OP表面活性剂存在下,pH 11.0的Na2B4O7-NaOH缓冲溶液中,该试剂能与镉生成2∶1型的红色配合物。配合物的最大吸收峰位于525 nm,表观摩尔吸光系数为2.04×105L.mol-1.cm-1。镉的质量浓度在0~0.60 mg/L范围内符合比尔定律。用拟定方法测定废水中微量镉,结果满意。  相似文献   

3.
报道了1-对偶氮苯基-3-(2-嘧啶)-三氮烯(APPMT)的合成及其与镉(Ⅱ)的显色反应。在非离子表面活性剂TritonX-100存在下,于pH11.4的Na2B4O7-NaOH缓冲介质中,镉(Ⅱ)与APPMT形成1∶3的红色配合物,试剂与配合物的最大吸收波长分别为430和520nm,表观摩尔吸光系数为1.99×105L.mol-1.cm-1,镉(Ⅱ)量在0~0.36μg/mL范围内符合比尔定律。  相似文献   

4.
报道了1-(4-硝基苯基)-3-(5-氯吡啶)三氮烯(NPCPDT)的合成及其与镉的显色反应研究。在Triton X-100的存在下,pH 11.5的Na2B4O7-NaOH缓冲溶液中,该试剂能与镉发生显色反应,镉与NPCPDT形成摩尔比为1∶3的黄色配合物,在440 nm处有一最大吸收,在535 nm处有一最大负吸收。以440 nm为参比波长,535 nm为测量波长进行双波长测定,表观摩尔吸光系数为2.68×105L.mol-1.cm-1,镉的质量浓度在0~0.48μg/mL范围内符合比尔定律。用拟定方法测定废水和环境水样中的微量镉。  相似文献   

5.
报道了1-(2-苯并咪唑)-3-[4-(苯基偶氮)苯基]-三氮烯(PIPAPT)的合成及与镉(Ⅱ)的显色反应。在非离子表面活性剂OP存在下,于pH 11.0 Na2B4O7-NaOH缓冲体系中,试剂与镉(Ⅱ)形成4∶1的橘红色配合物,其最大吸收波长位于523 nm,表观摩尔吸光系数为1.19×105L.mol-1.cm-1。镉质量浓度在0~0.7μg/mL范围内符合比尔定律。方法可用于水中微量镉的测定。  相似文献   

6.
报道了新显色剂1 偶氮苯3 (5 氯2 吡啶) 三氮烯的合成及其与镉的显色反应研究。在TX 100表面活性剂存在下,pH11.0的Na2B4O7 NaOH缓冲溶液中,该试剂与镉发生显色反应,生成3∶1的红色配合物。配合物的最大吸收峰位于530nm,表观摩尔吸光系数为2.42×105L·mol-1·cm-1。Cd2 质量浓度在0~480μg/L范围内符合比尔定律。用拟定方法可测定人发和废水中的微量镉。  相似文献   

7.
报道了新显色剂1-偶氮苯-3-(5-氰基-2-吡啶)-三氮烯的合成及其与铜的显色反应.在表面活性剂NP-10存在下,pH11.0的Na2B4O7-NaOH缓冲溶液中,该试剂与铜发生显色反应,生成31型的红色配合物,配合物的最大吸收峰位于535mm,表观摩尔吸光系数为1.43×105L·mol-1·cm-1.Cu2+质量浓度在0~480μg/L范围内符合比尔定律.用拟定方法测定合金中微量铜,结果令人满意.  相似文献   

8.
报道了1-(4-硝基苯基)-3-(4-羟基-6甲基-嘧啶)-三氮烯(NPHMPDT)的合成及其与镉的显色反应研究.在表面活性剂OP存在下,pH 11.0的Na2B4O7-NaOH缓冲溶液中,该试剂能与镉发生显色反应,镉与NPHMPDT形成摩尔比为1:3型的淡黄色配合物,在450 nm处有一最大正吸收,在540 nm处有一最大负吸收.以450 nm为参比波长,540 nm为测量波长进行双波长测定,表观摩尔吸光系数为4.88×105 L·mol-1·cm-1,镉的质量浓度在0~480 μg/L范围内符合比尔定律.  相似文献   

9.
研究了新试剂 1 -( 2 ,6 -二氯 -4 -硝基苯 ) -3 -( 4-硝基苯 ) -三氮烯与镉的显色反应。在 Triton X-1 0 0存在下 ,于 p H=9.8~ 1 1 .0的 Na2 B4 O7-Na OH缓冲溶液中 ,镉与试剂有高灵敏的显色反应 ,生成 1∶ 3型黄色配合物 ,最大吸收波长为 44 5nm。用双峰双波长法测定 ,其表观摩尔吸光系数为 2 .85× 1 0 5L·mol- 1·cm- 1。用拟定的方法测定了人发和废水中的镉含量 ,标准加入回收率分别为 1 0 4.5%和 1 0 5.8% ,相对标准偏差分别为 3 .2 %和 4.1 %。  相似文献   

10.
合成了新显色剂1-(4-甲基-6-羟基嘧啶)-3-(偶氮苯基)-三氮烯(MHPPAT)并研究了它与汞的显色反应. 在pH 10.0的Na2B4O7-NaOH缓冲溶液中, 壬基酚聚氧乙烯醚 (NP)表面活性剂存在下, 试剂与汞生成4∶1的紫红色配合物. 配合物的最大吸收峰位于520 nm, 表观摩尔吸光系数为2.88×105 Lmol-1cm-1. Hg2+质量浓度在0~4.80×10-4 g/L范围内符合比尔定律.  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

13.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

14.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

15.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

16.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

17.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

18.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

19.
20.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

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