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21.
手性配体立体选择性萃取分离扁桃酸对映体 总被引:6,自引:0,他引:6
Based on chiral ligand exchange, the distribution behavior of mandelic acid enantiomers in the two-phase system containing copper ion(Ⅱ)(Cu2+) and N-n-dedecane-L-hydroxyproline (L), was studied. At different pH, the partition of Cu2+ in the two-phase system containing N-n-dedecane-L-hydroxyproline, was investigated. The formation constant of binary cpmplex(Li2Cu) was obtained by regression. The influence of pH, concentrations of Cu2+ and chiral ligand, and solvents on partition coefficients(K) and separation factor(α), was discussed. The experimental results show that Li forms more stable ternary complex with D-mandelic acid than with L- mandelic acid. There is a large influence of pH on K and α. At low pH values (<3.5), formation of binary complexes is thermodynamically unfavourable. K and α are best when pH values are above 3.5 and the molar ratio of chiral ligand to Cu2+ is 2∶1. At the same time, solvents influence K and α very much. 相似文献
22.
众所周知,铑催化剂是醇类羰基化的有效催化剂,但是铑价格昂贵且对设备有腐蚀性,因此,寻找出对醇类羰基化催化活性好的非贵金属催化剂,对醇类羰化的工业化有十分重要的意义。 本文在温和条件下,合成了四种含有相同配体(Ph_2PPy)不同金属的有机配合物(金属基分别为Ni、Co、Pd、Fe),并探索了它们对乙醇羰基化反应的催化活性。 相似文献
23.
24.
Jun Fan Wei‐Guang Zhang Min‐Yu Tan Yu Tang Wei‐Sheng Liu Ning Tang Kai‐Bei Yu 《中国化学》2004,22(6):508-511
The La(III) complex with a new amide‐type tripodal ligand,2,2′.2″‐nitrilotris{[(2′‐benzylaminofomyl)‐phenoxylethyl)amine (L), was synthesized and characterized by X‐ray crystallographic analysis. Crystal data: C48H55.50LaN7O18.75, Mr=1169.40, monoclinic. space group, P21/n, a= 1.0644(3) nm. b=2.3889(5) nm, c= 2.1917(5) nm, β=90.65°, V=5.573(2) nm3, Z=1, Dc=1.394 g°cm?3, R1=0.0487, wR [1>2s?(I)]=0.1266. The results reveal that each La(III) ion binds to 9 oxygen atoms, three of which belong to carbonyl groups from three tripodal ligands and six to three bidentate nitrate groups and a two‐dimensional sheet of 4.82 networks is assembled by metal‐ligand coordination interaction. L, a heptadentate compound, merely acts as a tridentate bridging spacer due to its steric hindrance and links the La(III) ions as three‐connected nodes. 相似文献
25.
本文通过异氰酸酰化反应合成了含有脲基的苯乙炔新型配体及以它作为辅助配体的4′-(对甲基苯基)-6-苯基-2,2′-二联吡啶铂(II)络合物,初步研究了铂(II)络合物的光物理性质,发现由于脲基的存在,当浓度大于3.32×10-5mol/L时铂(II)络合物能够发生分子间簇集. 相似文献
26.
0IntroductionThestudyofcopper?complexesisinvestigatedinmanylaboratories.Amongthereasonsforcarryingouttheinvestigationofsuchspeciesaretheirstructuralfeatures犤1犦,theusefulnessofcopper?compoundsinorganicsyntheses犤2犦andthewell-documentedimpor-tanceofcopper?centersattheactivesitesofanumberofprotein犤3犦.Concerningcopper?carboxy-latesafurtherinterestexists,stemmingfromtheiruseinhomogeheouscatalysedhydrogenation犤4犦.Thecopper?bis(triphenylphosphine)cationisasoft,butflexi-bleacceptorionthatcanacc… 相似文献
27.
O. N. Babkina O. M. Chukanova E. E. Faingol"d N. M. Bravaya 《Russian Chemical Bulletin》2004,53(4):785-790
Quantitative characteristics of changes in the energy of charge transfer from -bonded ligands to metal are presented for the series of structurally similar ansa-metallocene complexes of IVB Group elements. The changes are caused by the solvation effect, replacement of -bonded chlorine ligands by methyl groups and of bridging ethylene groups by dimethylsilylene moieties, introduction of the methyl substituent into position 2 and phenyl substituent into position 4 of the indenyl system, variation of the transition metal in metallocene, and formation of complexes with polymethylalumoxane (MAO) at different AlMAO/Zr ratios. These effects are found to be additive. 相似文献
28.
具有C2对称轴的手性配体及其不对称催化反应 总被引:2,自引:0,他引:2
按配位原子的数目进行分类,综述了近年来研究较多的具有C2对称轴的手性配体及其相关的不对称催化反应,并对该类手性配体的设计做了分析和总结。参考文献79篇。 相似文献
29.
The reaction of B2H4 with acetylene has been studied by the MNDO method. It is shown that the reaction is exothermic and proceeds in two steps. The first step is the formation of a three-center -complex and this is the rate-determining step of the reaction. The second step is the rearrangement of the -complex to the product and this step requires a very small amount of activation energy. The activation barrier for the diboration reaction is 12.8 kcal/mol.The proposed mechanism is significantly different from those proposed earlier and explains all experimental data relating to this reaction. 相似文献
30.
A new way for synthesizing styrenic type of chiral resins grafting to multidentate ligand has been found. The synthetic scheme is proved to be practical by means of elemental anaysis, IR spectra and metal adsorbility. The resolving power of the new chiral ligand resins coordinated with copper (Ⅱ) as stationary phases has been discussed based on HPLC, and some points of view about the compositions of mobil phase and mechanism of resolution are presented. 相似文献