Question

文献翻译

In this Letter, we report
the synthesis and complexation behaviour of novel anion receptors
based on upper-rim substituted calix[4]arenes bearing amidic
functions which are responsible for the recognition and p-nitrophenyl
moieties as UV/Vis sensitive subunits.
The preparation of the novel anion receptors is depicted in
Scheme 1. The starting material, 25,26,27,28-tetrapropoxycalix[
4]arene (1), obtained by alkylation of the parent calix[4]arene
with PrI/NaH/DMF, was nitrated using NaNO3 in a TFA/acetic acid
mixture6 at room temperature. The resulting mixture of monoand
dinitro substituted products was separated by column
chromatography on silica gel to give the proximal 2a and distal
2b regioisomers in 19% and 21% yields, respectively. Subsequent
reduction with SnCl22H2O in hot ethanol led to the amino substituted
derivatives7 3a and 3b in 75% and 97% yields, respectively.
The corresponding amides were obtained by reaction with p-nitrobenzoyl
chloride in THF in the presence of Et3N as base. Stirring the
reaction mixture overnight at room temperature followed by
work-up gave the amides 4a (86%) and 4b (89%) in high yields.8
The structures of the receptors 4a,b were confirmed by 1H NMR
and MS analysis. Both 4a and 4b showed completely identical patterns
in ESI MS: a signal at m/z 943.39 (100%), corresponding to the
amide complex with a sodium cation [M+Na]+, and another peak at
m/z 959.36 (30%) matching with an [M+K]+ complex. The 1H NMR
spectrum (CDCl3) of the distal regioisomer 4b showed two doublets
(J = 13.5 Hz) due to methylene bridges (4.49 and 3.19 ppm),
typical for the cone conformation, while the aromatic singlet at
6.65 ppm confirmed the symmetrical disubstitution of the system.The expected splitting pattern of axial hydrogens (three doublets)
in 4a collapsed into one unresolved doublet at 4.38 ppm. Fortunately,
the multiplet due to the equatorial protons centred at
3.15 ppm confirmed the lower symmetry of the proximal derivative
4a (Cs symmetry) compared with that of 4b (C2v symmetry).
The UV/Vis titration experiments9 with selected anions were
performed in MeCN and CHCl3. The titrations resulted in welldefined
isosbestic points suggesting 1:1 binding stoichiometry
(Fig. 1). The stoichiometry could not be confirmed by Job analysis
because of the small absorbance changes induced by the complexation.
The obtained sets of recorded absorption spectra were analysed
by the non-linear least-squares method assuming 1:1
stoichiometry. It is well known that the complexation of neutral
receptors bearing amide or ureido functions is based on the hydrogen
bonding interactions of –NH– groups with anions. The resulting
complexation constants are expected to be solvent-dependent
with the highest values for the least competitive solvents (e.g.,
CHCl3). By contrast, the titrations in acetonitrile always showed
higher complexation constants than in chloroform (Table 1).
用翻译工具的无视

Answer 1

非常适合我的领域。稍候，正在翻译……
此文中，我们对含有官能团酰胺2（被确认为之中对紫外/可见光敏感的亚基）的杯芳烃上缘衍生物【4】 进行了综述。
新型阴离子受体的描述
1.原始物料，25,26,27,28-tetrapropoxycalix[4]arene (1), 杯[4]芳烃与PRI /氢化钠/二甲基甲酰胺进行父烷基化反应得到物，使用混合了6份置于保温箱中的三氟乙酸/醋酸的硝酸钠进行硝化。
混合用的单-二硝基替代物是通过分离硅胶中的柱层析并给近端的2A和远端2B分别加入19％和21％的区域异构体。随后通过二氯化锡减少热乙醇中的氨基酸取代衍生物7的3a和3b分别到75%和97%。

实验室比较忙，暂时不能继续了……

追问

没事，慢慢来

追答

相应的酰胺通过三乙胺为基的四氢呋喃中的P-硝基氯化反应。通过搅拌在室温下搁置一夜的反应混合物取得高比例的酰胺4a (86%) 和4b (89%)。4a，4b手提的结构经过1小时的核磁共振和质谱分析。 4a和4b在电喷雾质谱中显示出完全一致的模式：在m / z为943.39（100％）的信号，对应酰胺复杂的[M+Na]+;另一个高峰在m / z 为959.36（30％）的信号，[M+K]+匹配。对区域异构体4b进行一小时的核磁共振（CDCI3为溶剂），在亚甲基桥（4.49和3.19 PPM）处显示两个双峰（J = 13.5赫兹），为典型的圆锥体结构，而在6.65ppm的芳香单证实了该体系对称的双[二基]取代作用。
可以推测4a中的轴向氢分裂模式（三双峰）在4.38PPM溃变为未分裂的双峰。
幸运的是，由于赤道质子集中在3.15PPM，证实了近端衍生4A（Cs对称性）相比4B（C2v对称性）有更低的对称性。用选定的阴离子对紫外/可见光滴定实验9中的乙腈和氯仿。在定义清晰的等色滴定结果中显示了1:1结合的化学计量比。化学计量学无法确认分析结果，因为络合使得吸光度改变了诱导过程。
对吸收光谱获得的数据用非线性最小二乘法并按1:1的化学计量假设。众所周知，轴承酰胺或脲功能的中性受体的络合是基于氢键的NH-与阴离子的组合。由此产生的络合常数预计会对低溶溶剂（如氯仿）有极高的互溶性。相比较下，在乙腈的滴定中，则比氯仿滴定有更高的络合常数。