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21.
《Journal of Coordination Chemistry》2012,65(7):1115-1126
A UV-Vis spectrophotometric study of adduct formation of SalenH2 (1) and MII(Salen), where M?=?Mn (2), Fe (3), Co (4), Ni (5) and Cu (6) as donors with Me2SnCl2 as acceptor have been investigated in chloroform. Adducts (1a–6a) have been characterized by 1H, 13C and 119Sn NMR, IR and electronic spectroscopy and microanalysis. Formation constants and thermodynamic parameters were measured for 1 : 1 and 2 : 1 adducts at various temperatures (T?=?278 to 308 K). The data refinement was carried out with the SQUAD 84 program. The trend of formation constants of MII(Salen) complexes with Me2SnCl2 follows the order: Mn>Fe>Cu>Co>Ni. The formation constants for the free 1 and MII(Salen) with Me2SnCl2 changes according to the following trend: MII(Salen)>SalenH2 相似文献
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Tetrabutylammonium fluoride(TBAF) effectively facilitated a denitrative substitution reaction of electron-deficient nitroarenes with phenylthiotrimethylsilane(PhSTMS) under mild and base-free neutral conditions at room temperature,providing a practical and efficient synthesis of useful unsymmetrical diaryl thioethers.Nitroarenes bearing ortho-and para-positioned electron-withdrawing groups are the most reactive substrates,indicating that this reaction most possibly proceeded via the nucleophilic aromatic substitution(S_NAr) mechanism. 相似文献
24.
We have developed convenient methods for the synthesis of functionalized unsymmetrical dialkyl disulfides under mild conditions in very good yields. The designed method is based on the reaction of (5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)-disulfanyl derivatives 1 with functionalized alkyl thiolate anions, generated in situ from thioacetates 2 and sodium methoxide or butylamine. The developed method allows the preparation of unsymmetrical disulfides bearing additional hydroxy, carboxy, amino, azido, biotin, or maleimide functionalities. 相似文献
25.
Nader Ghaffari Khaligh 《催化学报》2014,35(7):1036-1042
3-Methyl-1-sulfonic acid imidazolium hydrogen sulfate has been used as an efficient, halogen-free,and reusable Brnsted acidic ionic liquid catalyst for the synthesis of ethyl-4-aryl/heteryl- hexahydro-trimehtyl-5-oxoquinoline-3-carboxylates via the one-pot condensation of dimedone with aryl/heteryl aldehydes, ethyl acetoacetate, and ammonium acetate under solvent-free conditions. This method has the advantage of being clean and simple, as well as providing the desired product in high yield over a short reaction time. Furthermore, the catalyst could be recycled and reused four times without any discernible reduction in activity. 相似文献
26.
双核Salen锌配合物对含氮小分子的分子识别研究 总被引:1,自引:0,他引:1
合成并表征了由一定长度烷氧链桥连的新型双核SalenZn配合物[简记为C10-(SalenZn)2],用紫外-可见光谱滴定方法测定了主体C10-(SalenZn)2与单齿客体咪唑(Im)、吡啶(Py)、双齿客体DABCO(1,4-重氮双环[2.2.2]辛烷)及吡嗪(Pyrazine)等4种含氮客体间的轴向配位反应的配位数及缔合常数.结果表明,双核主体与咪唑、吡啶和吡嗪的配位数均为2,与DABCO的配位数为1;各主客体体系的缔合常数按K0(Im)>K0(DABCO)>K0(Pyrazine)>K0(Py)顺序递减.各主客体缔合反应的热力学参数ΔrH0m,ΔrS0m和ΔrG0m结果表明,此类识别过程均为放热和熵减少的过程.采用1HNMR方法和分子动力学构象搜索方法对主体C10-(SalenZn)2与双齿客体DABCO间的分子识别行为及产物构型作了合理解释.通过量子化学计算进一步解释了主客体识别过程中光谱性质的变化. 相似文献
27.
以PhI(OAc)2为氧化剂,考察了1,3-二烷基咪唑硫酸酯系列离子液体中Mn(Salen)催化仲醇氧化的反应. 结果表明, 在MMISM-CH2Cl2(1:4,v:v)混合溶剂中, 反应条件为n((-苯乙醇): n(醋酸碘苯): n(催化剂1c)=50: 70: 1时, (-苯乙醇的转化率可以达到97.8%, 产物苯乙酮的选择性为100%, 远高于在纯CH2Cl2中的结果, 也要好于[bmim]BF4和[bmim]PF6对该反应的促进作用. 此外, BMISM及BEISE对催化剂1c有较好的稳定作用,催化剂可以重复使用. 相似文献
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用光谱滴定法研究了手性Salen金属配合物(SalenFe~(III), SalenCo~(II))与 四种咪唑类客体在CH_2Cl_2中的分子识别行为,发现手性Salen金属配合物与咪唑 ,N-甲基咪唑,2-甲基咪唑的配位数为2,与克霉唑的配位数为1。各识别体系缔 合常数的顺序对SalenFe~(III)为: K(Im) > K(2-MeIm) > K(N-MeIm) > K(GMZ), 对SalenCo~(II)为:K(Im) > K(2-MeIm) > K(N-MeIm)。测定的识别反应的△ _rG_m~0, △_rH_m~0, △_rS_m~0表明此类识别反应为放热、熵减少的过程,反应 体系存在焓-熵补偿关系。采用分子力学和量子化学方法进行的理论研究对实验结 果作出了合理的解释。 相似文献
30.
Shinya Harusawa 《Tetrahedron》2004,60(51):11911-11922
A novel measuring method (electroimmunoassay) of 17β-estradiol (E2) in urine or blood was proposed on the basis of a competition between E2 and a labeled E2 against an immobilizing antibody. To evaluate the principle, 3-{4-[17β-hydroxy-1,3,5(10)-estratrien-3-yloxy]butyldisulfanyl}-N-(6,7,9,10,12,13,15,16-octahydro-5,8,11,14,17-pentaoxabenzocyclopentadecen-2-yl) succinamic acid (1) was designed and synthesized as a novel aminobenzo-15-crown-5-containing E2 tethered with disulfide linkage. Two thiol-intermediates 5b and 19c were efficiently synthesized from mercaptosuccinic acid 7 and 4,4′-dithiodibutyric acid 12, respectively. Formations of disulfide linkages from less reactive thiols were examined and 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) could be employed for the formation of an unsymmetrical disulfide 20c from 5b and 19c. Then, removal of TMS- and allyl-protecting groups in 20c successfully afforded the crown ether-containing E21. 相似文献