磷酸根离子在阴离子交换树脂上的保留行为及其机理探讨

首次发现磷酸根离子在阴离子交换柱上以两个色谱峰流出。在研究磷酸根离子的保留行为的基础上,提出了Ｈ２ＰＯ－４在固定相中进一步离解的保留机理,即Ｈ２ＰＯ－４在与阴离子交换树脂交换基进行离子交换的过程中,由于树脂交换基和淋洗离子的电荷相互作用促使一部分Ｈ２ＰＯ－４进行第２级离解。由于Ｈ２ＰＯ－４和ＨＰＯ２－４在阴离子交换树脂上的保留值不同,导致磷酸根离子出现“双峰”。     

Anion Coordination Chemistry: Polyguanidinium Salts as Anion Complexones

The synthesis of a series of polyguanidinium salts of potential interest as anion complexones is described. Among the various synthetic methods investigated, the polyguanidinium salts were found to be most conveniently prepared from polyamines via polynitroguanidine intermediates. The complexation of phosphate and carboxylate anions by these complexones and by related polyammonium salts were studied by analysis of pH-metric titration data. The ligands studied from relatively stable complexes (log K_s = 2.0–4.0 for PO in water) which also present good selectivities in some cases. Both the stability and the selectivity of complexation are primarily governed by electrostatic forces and thus depend on charge accumulation in the interacting species; structural effects are also observed. Since the binding is primarily electrostatic, polyammonium salts from more stable complexes (at a given charge) than do polyguanidinium salts. However, whereas the complexation properties of the latter are independent of pH, the complexes of the former are observed only in the limited ranges of pH where both the protonated polyamine and the anion of interest can coexist. The polycationic ligands may, in principle, form chelate type anion complexes. Comparison with the corresponding single binding sites reveals an increase in complexation constant of about two or three orders of magnitude; this may be considered as a thermodynamic indication of a chelate effect for the polydentate ligands (by analogy with the well known effects displayed by cation complexones); however, structural data on the formation of chelate ‘rings’ are not yet available. The nature of the complexes and the prospects of anion complexones in various fields are discussed.     

芳酰基硫脲受体的合成及对阴离子识别研究

设计合成了3种芳酰基硫脲受体分子. 利用紫外-可见吸收光谱考察了其与F^－, Cl^－, Br^－, AcO^－, HSO₄^－, H₂PO₄^－等阴离子的作用. 结果表明该类受体分子与阴离子形成氢键配合物. 加入F^－, AcO^－时, 溶液立刻由无色变为黄色, 而加入其它阴离子则无变化, 从而实现对这两种阴离子的裸眼识别. 结果表明受体分子与阴离子间形成1∶1型的配合物. ¹H NMR滴定及质子溶剂效应为受体分子与阴离子间的氢键作用本质提供了直接依据.     

Anion radicals of polyphenylsiloxanes

The anion radicals of a number of siloxanes bearing phenyl and methyl substituents have been prepared by metal reduction. The cleavage and reaction mechanisms of these radica s have been studied by ESR, and interpretations have been made regarding the structures of the radicals.     

The Trifluoromethyl Anion

First evidence for the existence of free trifluoromethyl anion CF₃⁻ has been obtained. The 3D‐caged potassium cation in [K(crypt‐222)]⁺ is inaccessible to CF₃⁻, thus rendering it uncoordinated (“naked”). Ionic [K(crypt‐222)]⁺ CF₃⁻ has been characterized by single‐crystal X‐ray diffraction, solution NMR spectroscopy, DFT calculations, and reactivity toward electrophiles.     

The Trifluoromethyl Anion

First evidence for the existence of free trifluoromethyl anion CF₃^? has been obtained. The 3D‐caged potassium cation in [K(crypt‐222)]⁺ is inaccessible to CF₃^?, thus rendering it uncoordinated (“naked”). Ionic [K(crypt‐222)]⁺ CF₃^? has been characterized by single‐crystal X‐ray diffraction, solution NMR spectroscopy, DFT calculations, and reactivity toward electrophiles.     

The Anion Binding Affinity Determines the Strength of Anion Specificities of Thermosensitive Polymers

In this work,we demonstrate that the strength of anion specificities of thermosensitive polymers is determined by the affinity ofdirect anion binding to the polymers.We have prepared a series of thermosensitive statistical copolymers with distinct thermoresponsive behaviors.The anions can specifically interact with the different types of thermosensitive polymers in very different strengths.A similar strength of specific anion effects on thermoresponsive behaviors can be observed at very different salt concentrations for the different types of thermosensitive polymers.A stronger anion binding to the thermosensitive polymers gives rise to a more obvious anion specificity and vice versa.The work presented here opens up opportunities for the application of ion binding affinity to modulate the strength of ion specificities of thermosensitive polymers.     

Gels Based on Anion Recognition Between Triurea Receptor and Phosphate Anion

Anion recognition between the triurea receptor and phosphate anion is demonstrated as the cross‐linkage to build supramolecular polymer gels for the first time. A novel multi‐block copolymer ( 3) is designed to have functional triurea groups as cross‐linking units along the polymer main chain. By virtue of anion coordination between the triurea receptor and phosphate anion with a binding mode of 2:1, supramolecular polymer gels are then prepared based on anion recognition using 3 as the building block.

     

用于二元合金团簇负离子研究的光电子能谱仪

A home-made magnetic-bottle time-of-flight anion photoelectron spectrometer（PES）for the investigation of binary metal cluster geometry and electron structure is described. The photoelectron spectrometer is installed near the first space focus of home-made reflectron time of flight mass spectrometer（RTOFMS）,coupled with laser ablation,pulse supersonic molecular carrier gas cluster source. The magnetic-bottle photoelectron spectrometer's resolution is about 0. 1 eV for 1 eV photoelectrons. The adiabatic electron affinity energies of neutral clusters and some features relative to their excited states can be obtained from the spectra,i. e. ,from the anion's spectra,not only the features of the anion but also the neutral clusters' features can be investigated. The detailed design,construction,and operation of the new apparatus are presented. And studied PbM-（M = Cu,Ag,Au）binary metal cluster anions,the results give clear diagram about their structures and the bond interactions. The adiabatic electron affinity energies obtained by the photoelectron spectrometer agree well with the calculated results using relativistic density functional theory（DFT）method. It show that this anion photoelectron spectrometer can be well used in studying binary metal cluster anions in the experiment condition.     

喹啉类主体分子的设计合成与阴离子识别

合成了系列 5 ( 8 羟基喹啉 )偶氮苯衍生物 ,研究了取代基对其吸收光谱的影响 ,比较了不同主体化合物对阴离子亲合能力的差异 .研究结果表明 :5 ( 8 羟基喹啉 )偶氮 4′ 甲基苯对F-具有选择性识别作用 ,主客体分子间形成 1∶1型阴离子配合物 ,其最大吸收波长为 5 0 8nm ,溶液颜色由无色变为红色 ,配合物的稳定常数为 2 5× 10 4mol-1·L .其它阴离子如AcO-,H2 PO-4,HSO-4,ClO-4,Cl-和Br-等均不影响主体与F-的显色反应 ,据此建立了选择性识别氟离子新体系 .     

Deprotonation of a Hydridoborate Anion

The first deprotonation of a borohydride anion was achieved by treatment of [BH(CN)₃]⁻ with strong non‐nucleophilic bases, which resulted in the formation of alkali‐metal salts of the tricyanoborate dianion B(CN)₃²⁻ in up to 97 % yield and 99.5 % purity. [BH(CN)₃]⁻ is less acidic than (Me₃Si)₂NH but a stronger acid than i Pr₂NH. Less sterically hindered, more nucleophilic bases such as PhLi and MeLi mostly attack a CN group under formation of imine dianions [RC(N)B(CN)₃]²⁻, which can be hydrolyzed to ketones of the [RC(O)B(CN)₃]⁻ type. The boron‐centered nucleophile B(CN)₃²⁻ reacts with CO₂ and CN⁺ reagents to give salts of the [B(CN)₃CO₂]²⁻ dianion and the tetracyanoborate anion [B(CN)₄]⁻, respectively, in excellent yields.     

取代环戊二烯负离子的三甲基硅基化

以６,６－二烷基富烯与甲基锂、苯基锂或对甲苯基锂所犁 取代环戊二烯基锂与三甲基氯硅烷反应,合成了１１个新的三甲基硅基环戊二烯化合物,其结构经元素分析、ＩＲ和＾１ＨＮＭＲ确证。     

Visible-Light-Switchable Tellurium-Based Chalcogen Bonding: Photocontrolled Anion Binding and Anion Abstraction Catalysis

Exploring new noncovalent bonding motifs with reversibly tunable binding affinity is of fundamental importance in manipulating the properties and functions of supramolecular self-assembly systems and materials. Herein, for the first time, we demonstrate a unique visible-light-switchable telluro-triazole/triazolium-based chalcogen bonding (ChB) system in which the Te moieties are connected by azobenzene cores. The binding strengths between these azo-derived ChB receptors and the halide anions (Cl⁻, Br⁻) could be reversibly regulated upon irradiation by visible light of different wavelengths. The cis-bidentate ChB receptors exhibit enhanced halide anion binding ability compared to the trans-monodentate receptors. In particular, the telluro-triazolium-based ChB receptor can achieve both high and significantly photoswitchable binding affinities for halide anions, which enable it to serve as an efficient photocontrolled organocatalyst for ChB-assisted halide abstraction in a Friedel–Crafts alkylation benchmark reaction.     

Isolable Anion Radicals of Nitrosoarenes

Summary of main observation and conclusion The rich redox chemistry of nitrosoarenes has rendered these reactive molecules very useful in modern synthetic and material chemistry.Electrochemical studies have revealed the capability of nitrosoarenes to undergo one-electron oxidation or reduction reaction for a long time.However,the isolation and structural characterization of nitrosoarene radical compounds deviating the stabilization of transition-metal have not been achieved.Investigation on the reduction reaction of nitrosoarenes bearing steric demanding substituents has now revealed that the interaction of 2,6-dimesityl-1-nitroso-benzene(DmpNO)or 2,4,6-tri(tert-butyl)-1-nitroso-benzene(TtpNO)with KC8 and crypt-2,2,2 can produce the corresponding anion radical compound[K(crypt-2,2,2)][DmpNO](1)or[K(crypt-2,2,2)][TtpNO](2)in good isolated yield.Compounds 1 and 2 represent the first examples of isolable nitrosoarene radical compounds deviating the stabilization of transition-metal,and have been characterized by single-crystal X-ray diffraction study,electron paramagnetic resonance(EPR)spectroscopy,and elemental analysis.Theoretical study in collaboration with the characterization data revealed that the unpaired spin in[DmpNO]·-and[TtpNO]·-delocalizes on the nitroso and the central phenyl groups.     

Amidocrownophanes as Anion Receptor

Crownophanes composed of 28-membered ring atoms having two hydroxy groups, two amide groups, and aromatic parts such as naphthalene rings and either pyridine or benzene ring, can bind anions with high affinity and selectivity. The anion-coordination ability of these species has been observed by ¹H NMR techniques. As anion guest molecules, we selected some halides, dihydrogenphosphate and acetate ions. It has been found that amidocrownophanes, 3 and 4, can recognize anions in the order;H₂PO ₄ ⁻ >F⁻>CH₃COO⁻>Cl⁻>>Br⁻ and I⁻, while not only 1, 2, and 5 having no hydroxy group but also 6 having 27-membered ring have no ability for anion recognition under the same conditions. In order to exhibit the recognition ability for anion receptor, plural amide groups, hydroxy groups, and m-phenylene or 1,6-pyridyl rigid part play an important role in this macrocyclic system.     

有机负离子重氮树脂

重氮树脂作为阴图ＰＳ版的感光剂已有很多专利［１～４］．它是由二苯胺－４－重氮盐或取代二苯胺－４－重氮盐与多聚甲醛在浓硫酸中缩聚制得，由于耐候性与亲油墨性差，实际应用时，需将ＨＳＯ－４转换为有机负离子，如与十二烷基苯磺酸钠反应，但常导致热分解温度（Ｔｄ...     

含氮杂环类阴离子受体*

含氮杂环类阴离子受体是目前超分子阴离子识别领域研究的热点之一。此类受体具有主体结构丰富、可调节性强、识别范围广、选择性强、灵敏度高等优点。本文综述了以吡咯、吲哚、咪唑、吡唑等含氮杂环为识别基团的阴离子受体的设计原理、识别性能和机理,展望了该领域的发展方向。