多分支中性受体的合成及αω-二羧酸阴离子识别研究

Two new multi-armed neutral receptors 1 and 2 containing thiourea and amide groups were synthesized by simple steps in good yields. Receptors 1 and 2 have a better selectivity and higher association constants for malonate anion than other anions examined by the present work. In particular, distinct color changes were observed upon addition of dicarboxylate anions to the solution of 1 in DMSO. The UV-Vis and fluorescence spectra data indicate that a 1 ： 2 stoichiometry complex was formed between compound 1 or 2 and dicarboxylate anions of shorter carbon chain, and a 1 ： 1 stoichiometry complex was formed between compound 1 or 2 and dicarboxylate anions of longer carbon chain through hydrogen bonding interactions.     

Synthesis of the Anionic Fluororeceptors and Recognition Property for α,ω-Dicarboxylate

Anions, especially dicarboxylates, play an important role in chemical and biological processes,[1] dicarboxylates are critical components of numerous metabolic processes including, for instance, the citric acid and glyoxylate cycles.[1a]They also play an important role in the generation of high-energy phosphate bonds and in the biosynthesis of important intermediates.[1b] To date, several receptors containing different functional groups for selective binding of dicarboxylate anions have been reported.[2,3] However, the sensors based on the fluorescence emission for dicarboxylate anions are still rare.3 In this paper, we report the synthesis and binding properties of two new neutral anion receptors (1 and 2).     

Synthesis of colorimetric receptors for dicarboxylate anions: a unique color change for malonate

Three new chromogenic receptors (1, 2, and 3) containing p-nitrophenyl or p-nitronaphthyl or methyl groups appended to the thiourea groups were synthesized and characterized. Upon addition of a series of dicarboxylate anions to receptor 1 in DMSO, only the appearance of the solution of receptor 1 with malonate showed a color change from blue to yellow which can be detected by the naked eye at parts per million. With the addition of the series of dicarboxylate anions to receptor 2, the solutions showed an indistinct intense dark-red color. Whereas the addition of the same dicarboxylate anions to receptor 3, the solutions did not induce any color change. Thus, for the unique color change, the receptor 1 can act as an optical chemosensor for the malonate anion even in the presence of other dicarboxylate anions.     

Supramolecular squares with Mo2(4+) corners

Seven complexes obtained by reacting the quadruply bonded complex [Mo2(cis-DAniF)2(CH3CN)4](BF4)2 (DAniF = N,N'-di-p-anisylformamidinate) and (Bun4N+)2(Carb2-), where Carb2- is a dicarboxylate anion, have been found to have a ratio of dimetal unit to dicarboxylate of 1:1. As noted by the carboxylate linker, the compounds are oxalate, 1, fumarate, 2, ferrocene dicarboxylate, 3, 4,4'-biphenyldicarboxylate, 4, acetylenedicarboxylate, 5, tetrafluorophthalate, 6, and carborane dicarboxylate, 7. Structural characterization of 1-4 revealed a square of dimolybdenum units linked by the dicarboxylate anions, each having an interstice capable of accommodating specific solvent molecules. Results of NMR studies of all seven compounds are consistent with the presence of a highly symmetrical structure. These compounds display a rich electrochemical behavior that is affected by the nature of the carboxylate group.     

Dicarboxylate recognition by two macrobicyclic receptors: selectivity for fumarate over maleate

Two ditopic polyamine macrobicyclic compounds have been studied as receptors for the recognition of dicarboxylate anions of varying chain length in aqueous solution. One of the receptors consists of two tris(2-aminoethyl)amine-derived binding subunits separated by p-xylyl spacers, while the other is a heteroditopic compound, combining two different head units, a tren-derived and a 2,4,6-triethylbenzene-derived one, also separated by p-xylyl spacers. The acid-base behavior of the compounds as well as their binding ability with oxalate (oxa(2-)), malonate (mal(2-)), succinate (suc(2-)), glutarate (glu(2-)), maleate (male(2-)) and fumarate (fum(2-)) anions were studied by potentiometry at 298.2 K in aqueous solution and at ionic strength 0.10 M in KTsO. NMR studies were also performed to obtain structural information in solution on the supermolecules formed by association of the protonated macrobicycles with the dicarboxylate substrates. The results revealed that both compounds are able to form stable associations with the dianionic substrates in competitive aqueous solution, with unprecedented selectivity for fum(2-) over other dicarboxylate competitors, including its cis isomer male(2-). In addition it was found that although the selectivity pattern is unaffected by the introduction of the 2,4,6-triethylbenzene head unit, the affinity toward dicarboxylates is significantly reduced. Therefore, the comparison between the binding behavior of these two receptors showed the effect of the increased rigidity and lipophilicity of the receptor with the 2,4,6-triethylbenzene head unit in the binding properties and the selectivity pattern.     

A Multi-armed Neutral Receptor for α,ω-Dicarboxylate Anions

A multi-armed neutral anion receptor (1) bearing multiple amide and thiourea binding sites was synthesized. Receptor 1 forms 1:2 complexes with dicarboxylate anions, and the sensitivity for recognition of dicarboxylate depends strongly on the chain length of these dicarboxylate anions. Addition of the anions caused a considerable change in the absorbance and fluorescent intensity of the host solution and a consequent visible color change.     

Development of colorimetric receptors for selective discrimination between isomeric dicarboxylate anions

Three new chromogenic receptors (1, 2, and 3) containing p-nitrophenyl or p-nitronaphthyl group appended to the thiourea units or containing p-nitrophenyl group appended to the urea moiety were synthesized and characterized. Upon addition of a series of isomeric dicarboxylate anions to receptor 1 in DMSO/H₂O (80:20 v/v), the appearance of the solution of receptor 1 with maleate or phthalate showed color changes from blue to green or blue to dark-green, respectively, which those can be detected by naked eye at parts per million. Similar experiments were repeated using 2, the solution showed a distinct color change from blue to pink only when 2 is formed as a complex with maleate. Whereas, the addition of the same isomeric dicarboxylate anions to receptor 3, did not induce any color change. Thus, for unique color change, both receptors 1 and 2 can act as optical chemosensors for recognition of maleate versus fumarate. In addition, the receptor 1 can also be a colorimetric receptor for selective discrimination between aromatic isomeric dicarboxylate anions.     

Cluster phase chemistry: gas-phase reactions of anionic sodium salts of dicarboxylic acid clusters with water molecules

A homologous series of anionic gas-phase clusters of dicarboxylic acids (oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid) generated via electrospray ionization (ESI) are investigated using collision-induced dissociation (CID). Sodiated clusters with the composition (Na(+))(2)(n+1)(dicarboxylate(2-)(n+1) for singly charged anionic clusters, where n = 1-4, are observed as major gas-phase species. Isolation of the clusters followed by CID results mainly in sequential loss of disodium dicarboxylate moieties for the clusters of succinic acid, glutaric acid, and adipic acid (C4-C6). However, all oxalate (C2) and malonate (C3) clusters and dimers (n = 1) of succinate (C4) and glutarate (C5) exhibit more complex chemistry initiated by collision of the activated cluster with water molecules. For example, with water addition, malonate clusters dissociate to yield sodium acetate, carbon dioxide, and sodium hydroxide. More generally, water molecules serve as proton donors for reacting dicarboxylate anions in the cluster and introduce energetically favorable dissociation pathways not otherwise available. Density functional theory (DFT) calculations of the binding energy of the cluster correlate well with the cluster phase reactions of oxalate and malonate clusters. Clusters of larger dicarboxylate ions (C4-C6) are more weakly bound, facilitating the sequential loss of disodium dicarboxylate moieties. The more strongly bound small dicarboxylate anions (oxalate and malonate) preferentially react with water molecules rather than dissociate to lose disodium dicarboxylate monomers when collisionally activated. Implications of these results for the atmospheric aerosol chemistry of dicarboxylic acids are discussed.     

含硫脲和酰胺单元的新型杯［4］芳烃中性氟离子受体

Two-armed neutral anion receptors (4,5), calix[4]arenes beating thiourea and amide binding sites, were prepared and examined their anion-binding ability by the UV-vis spectra. The results of non-linear curve fitting and Job plot indicate that 4 or 5 forms 1：1 stoichiometry complex with fluoride by hydrogen bonding interactions. Receptors 4 and 5 have an excellent selectivity for fluoride but have no binding ability with acetate, dihydrogen phosphate and the halogen anions (Cl^-,Br^-,I^-).     

The simplest supramolecular complexes containing pairs of Mo(2)(formamidinate)(3) units linked with various dicarboxylates: preparative methods, structures, and electrochemistry

Twelve compounds containing two quadruply bonded Mo(2)(DAniF)(3) (DAniF = N,N'-di-p-anisylformamidinate) units linked by dicarboxylate anions have been prepared in high purity and good yields. All of these compounds have been characterized by crystallography and NMR. The dinuclear pairs display electrochemical behavior which is controlled by the nature of the bridging dicarboxylate group. As described by the linkers, the compounds are oxalate, 1; acetylene dicarboxylate, 2; fumarate, 3; tetrafluorophthalate, 4; carborane dicarboxylate, 5; ferrocene dicarboxylate, 6; malonate, 7; succinate, 8; propane-1,3-dicarboxylate, 9; tetrafluorosuccinate, 10; bicyclo[1.1.1]pentane-1,3-dicarboxylate, 11; and trans-1,4-cyclohexanedicarboxylate, 12.     

Self-assembled arene-ruthenium-based rectangles for the selective sensing of multi-carboxylate anions

Novel arene-ruthenium [2+2] metalla-rectangles 4 and 5 have been synthesized by self-assembly using dipyridyl amide ligand 3 and arene-ruthenium acceptors (arene: benzoquinone (1), naphthacenedione (2)) and characterized by NMR spectroscopy and ESI-MS. The solid-state structure of 5 was determined by X-ray diffraction and shows encapsulated diethyl ether molecule in the rectangular cavity of 5. The luminescent 5 was further used for anion sensing with the amidic linkage serving as a hydrogen-bond donor site for anions and the ruthenium moiety serving as a signaling unit. A UV/Vis titration study demonstrated that although 5 interacts very weakly with common monoanions as well as with flexible dicarboxylate anions such as malonate and succinate, it displays significant binding affinity (K>10(3) in MeOH) for rigid multi-carboxylate anions such as oxalate, citrate, and tartrate, exhibiting a 1:1 stoichiometry. It has been suggested that 1:1 bidentate hydrogen bonding assisted by appropriate geometrical complementarity is mainly responsible for the increased affinity of 5 towards such anions. A fluorescence titration study revealed a large fluorescence enhancement of 5 upon binding to multi-carboxylate anions, which can be attributed to the blocking of the photoinduced electron-transfer process from the arene-Ru moiety to the amidic donor in 5 as a result of hydrogen bonding between the donor and the anion.     

Study on the Anion Recognition Properties of Synthesized Receptors （Ⅲ）： Convenient Synthesis and Anion Recognition Property of Bisthiosemicarbazone Derivative

A new series of bisthiosemicarbazone derivative receptors(1,2 and 3)have been synthesized by simple steps ingood yields.Their anion recognition properties were studied by UV-Vis and ~1H NMR spectroscopy.The resultshowed that the receptors 1,2 and 3 all had a better selectivity to F~-,CH_3COO~- and H_2PO_4~-,but no evidentbinding with Cl~-,Br~-,I~-,NO_3~- and HSO_4~-.Upon addition of the three anions to the receptors in DMSO,thesolution acquired a color change from colorless to dark yellow that can be observed by the naked-eyes,thus the re-ceptors can act as fluoride ion sensors even in the presence of other halide ions.The data showed that it was regularthat the three receptors had different binding ability with the three anions.For the same anion,the association con-stants followed the trend:receptor 1>3>2.The UV-Vis data indicates that a 1:1 stoichiometry complex isformed through hydrogen bonding interactions between compound 1,2 or 3 and anions.     

Chlorido(dimethyl 2,2′‐bipyridine‐4,4′‐dicarboxylate‐κ2N,N′)(η5‐pentamethylcyclopentadienyl)rhodium(III) chloride 1‐hydroxypyrrolidine‐2,5‐dione disolvate

The title complex, [Rh(C₁₀H₁₅)Cl(C₁₄H₁₂N₂O₄)]Cl·2C₄H₅NO₃, has been synthesized by a substitution reaction of the precursor [bis(2,5‐dioxopyrrolidin‐1‐yl) 2,2′‐bipyridine‐4,4′‐dicarboxylate]chlorido(pentamethylcyclopentadienyl)rhodium(III) chloride with NaOCH₃. The Rh^III cation is located in an RhC₅N₂Cl eight‐coordinated environment. In the crystal, 1‐hydroxypyrrolidine‐2,5‐dione (NHS) solvent molecules form strong hydrogen bonds with the Cl⁻ counter‐anions in the lattice and weak hydrogen bonds with the pentamethylcyclopentadienyl (Cp*) ligands. Hydrogen bonding between the Cp* ligands, the NHS solvent molecules and the Cl⁻ counter‐anions form links in a V‐shaped chain of Rh^III complex cations along the c axis. Weak hydrogen bonds between the dimethyl 2,2′‐bipyridine‐4,4′‐dicarboxylate ligands and the Cl⁻ counter‐anions connect the components into a supramolecular three‐dimensional network. The synthetic route to the dimethyl 2,2′‐bipyridine‐4,4′‐dicarboxylate‐containing rhodium complex from the [bis(2,5‐dioxopyrrolidin‐1‐yl) 2,2′‐bipyridine‐4,4′‐dicarboxylate]rhodium(III) precursor may be applied to link Rh catalysts to the surface of electrodes.     

1,10-邻菲啰啉并咪唑衍生物阴离子受体的合成及识别性能

设计合成了2个1,10-邻菲啰啉并咪唑衍生物阴离子受体2-(2-羟基苯基)-1H-咪唑[4,5-f][1,10]邻菲啰啉(1)和2-(2-羟基-5-溴苯基)-1H-咪唑[4,5-f][1,10]邻菲啰啉(2), 受体2的结构由X射线单晶衍射分析确证. 通过紫外-可见光谱滴定及 ¹H NMR滴定研究了这2个受体对F^-, Cl^-, Br^-, I^-, H₂PO₄^-和AcO^- 6种阴离子的识别传感作用及作用机理. 结果表明, 受体对AcO^-, F^-和H₂PO₄^-有较强的传感作用, 溶液颜色由淡黄色变为黄色; 对Cl^-的作用较弱; 而对Br^-和I^-则无明显作用. 通过机理研究发现, 受体与F^-, H₂PO₄^-和AcO^-形成1: 1的氢键超分子, 当阴离子的量超过受体的1倍以后, 咪唑氮上的氢转移到阴离子; 受体与Cl^-以氢键形成超分子复合物, 而与Br^-和I^-作用很弱.     

Connecting pairs of dimetal units to form molecular loops

Four compounds consisting of molecular loops formed from two quadruply bonded Mo2(DAniF)2 (DAniF = N,N'-di-p-anisylformamidinate) units linked by two dicarboxylate anions have been prepared in high purity and essentially quantitative yields. These compounds have been characterized by crystallography and NMR spectroscopy and display electrochemical behavior dependent on the nature of the dicarboxylate anion. However, the electronic communication between the two Mo2(4+) units is not strong. As denoted by the dicarboxylate linkers, the compounds are malonate, 1, 1,4-phenylendiacetate, 2, homophthalate, 3, and trans-cyclopentane-1,2-dicarboxylate, 4.     

Low-temperature photoelectron spectroscopy of aliphatic dicarboxylate monoanions, HO2C(CH2(nCO2- (n = 1-10): hydrogen bond induced cyclization and strain energies

Photoelectron spectra of singly charged dicarboxylate anions HO(2)C(CH(2))(n)CO(2)(-) (n = 1-10) are obtained at two different temperatures (300 and 70 K) at 193 nm. The electron binding energies of these species are observed to be much higher than the singly charged monocarboxylate anions, suggesting that the singly charged dicarboxylate anions are cyclic due to strong intramolecular hydrogen bonding between the terminal -CO(2)H and -CO(2)(-) groups. The measured electron binding energies are observed to depend on the chain length, reflecting the different -CO(2)H...(-)O(2)C- hydrogen bonding strength as a result of strain in the cyclic conformation. A minimum binding energy is found at n = 5, indicating that its intramolecular hydrogen bond is the weakest. At 70 K, all spectra are blue shifted relative to the room-temperature spectra with the maximum binding energy shift occurring at n = 5. These observations suggest that the cyclic conformation of HO(2)C(CH(2))(5)CO(2)(-) (a ten-membered ring) is the most strained among the 10 anions. The present study shows that the -CO(2)H...(-)O(2)C- hydrogen bonding strength is different among the 10 anions and it is very sensitive to the strain in the cyclic conformations.     

Synthesis under Micromave Irradition and Crystal Structure of 4''-Acetylbenzo-15 -crown-5thiosemicarbazone

The title compound is a bifunctional receptors including a thiourea group and a crown ether ring. Due to many possible potentials as a new class of reagents for membrane transports,ion-selective electrodes as well as reaction catalysts, the design and synthesis of bifunctional receptors for simultaneous binding of cations and anions is of ongoning interest in srprarnolecular chemistry1-5. In bifunctional receptors, the binding sites for anions and cations are covalently linked so as to exhibit allosteric or cooperative complexation where the binding affinity for anions(cations)is modified as a result of the cation(anion) complexation.Literature[6] reported that the ability of the thiourea group to bind anions is significantly enhanced when Na+ is bound to the crown moiety. To date, however only a few receptors of this class have been reported.6-8In this paper, we report an improved procedure under microwave irradiation that gives higher yields of title compound and needs fewer reaction times than traditional method.The structure of this compound was determined by IR ,element analysis and X-ray analysis.Scheme 1 The reaction equationThe crystal belongs to triclinic crystal system, P-1 space group, a=0.9547(0)nm, b=1.3637(3)nm,c=1.6029(3)nm, α =75.33(3) , β =83.62(3) , γ =70.99(3) ,Z=4,Dc=1.335g/cm3,F(000)=816,R1= 0.0557 ,wR2=0.1281. It is assembled into a three-dimensionalsupramolecule by intermolecular hydrogen bonds.     

间苯二甲酰腙分子钳的合成及阴离子识别研究

设计合成了3种新型间苯二甲酰腙类化合物,利用UV-Vis及¹H NMR考察了其与F^-、Cl^-、Br^-、I^-、CH₃COO^-、HSO₄^-、H₂PO4-、ClO4-阴离子的相互作用。结果表明,主体分子4a(双对硝基苯并呋喃甲醛间苯二甲酰腙)在DMSO溶液中对F-和CH₃COO-有显著识别效果,溶液颜色由黄色变为深黄色和棕红色。通过¹H NMR滴定及质子溶剂效应进一步证明,主体分子与阴离子之间是以氢键作用方式相结合。Job曲线表明,主客体间形成1：1型氢键络合物。基于实验结果,探讨了主客体间形状和大小匹配对识别能力的影响以及主客体之间的识别模式。     

Synthesis of the anionic fluororeceptors based on thiourea and amide groups and recognition property for α,ω-dicarboxylate

Three new neutral receptors (1, 2 and 3) containing thiourea and amide groups were synthesized by simple steps in good yields. The binding properties for anions of 1, 2 and 3 were examined by UV-vis, fluorescence, and ¹H NMR spectroscopy. Receptors 1, 2 and 3 all had a better adipate anion selectivity by comparison with other dicarboxylate anions. The association constants of 1, 2 and 3 with adipate were higher as compared to other anions (malonate, succinate, glutarate). In particular, a distinct color change was observed from light yellow to orange-red upon addition of adipate to the solution of 1 in DMSO. The UV-vis and fluorescence data indicate that a 1:1 stoichiometry complex is formed between compound 1, 2 or 3 and dicarboxylate anions through hydrogen bonding interactions.     

Modular assembly of a preorganised, ditopic receptor for dicarboxylates

Two types of calix[4]arene derived hosts for anions with, respectively, 1,3-alternate and cone conformations have been prepared; the 1,3-alternate system binds dicarboxylate anions in a ditopic manner while the cone compounds are deprotonated by carboxylates.