共查询到20条相似文献,搜索用时 15 毫秒
1.
To avoid the deprotonation events occurred in the receptor upon recognition of basic anions, a novel C3v-symmetric anion receptor 2 with two amide groups appended in each arm was designed and synthesized by using the trindane tricarboxylic acid as tripodal molecular framework. The anion recognition ability by 2 was examined by 1H NMR titration study in DMSO-d6, which revealed that the addition of H2PO4? guests caused substantial downfield shifts of the amide-NH protons peaks due to the formation of a host-guest complex in 1:1 binding stoichiometry with the estimated binding constant (Ka) of 244?M?1. No noticeable binding of 2 was observed with other tested anions such as F?, Cl?, Br?, I?, NO3? and HSO4? under similar conditions. 相似文献
2.
In this paper, a novel tripodal fluorescent receptor based on naturally occurring coumarin was synthesized and its ionic recognition properties were fully investigated by spectroscopic techniques. As revealed by the results, tripodal 1 exhibits excellent selectivity toward copper(II) by forming a 1:1 complex with triazole N as the main binding sites. And the resulted 1·Cu2+ complex shows recognition ability toward H2PO4? by metal displacement approach. The recognition mechanism was further investigated by computer calculation. 相似文献
3.
An anthracene-based diamidine (1) ‘turn-on’ fluorescent probe for the detection of dicarboxylic acids has been designed and synthesized. The fluorescence spectra of the diamidine 1 with carboxylic acids that showed two different fluorescence bands, which corresponded to the amidinium-carboxylate (λem=430-440 nm), and amidinium (λem=460-470 nm as a broad band) formation, were confirmed by DOSY NMR and TD-DFT calculations. These different fluorescence bands showed the binding mode of carboxylic acids and the stability of formed complexes toward diamidine 1. The fluorescent detection of amidinium-carboxylate formation using diamidine 1 was applicable to the detection of α,ω-dicarboxylic acids (C6-C13) and succeeded in the detection of α,ω-dicarboxylic acid (adipic acid) in human urine. 相似文献
4.
Thiourea-containing coumarins 1, 2 have been designed and synthesized via reaction of 6-aminomethylcoumarin and the corresponding isothiocyanates. Their anion-binding ability has been examined using UV-vis, fluorescence and 1H NMR. The anion recognition takes place through charge neutral thiourea receptor sites with concomitant fluorescence quenching of the coumarin moiety with 1 showing a strong binding to C6H5COO− over F− with a distinct change in color. 相似文献
5.
6.
《Tetrahedron: Asymmetry》2005,16(18):3042-3048
Chiral fluorescence receptors 1 and 2 were synthesized and their structures characterized by IR, 1H NMR, 13C NMR, MS spectra, and elemental analysis. The chiral recognition abilities of 1 and 2 were studied by 1H NMR and fluorescence spectra. The results demonstrate that receptors 1 and 2 with bis(tetrabutylammonium) dibenzoyl tartrate formed a 1:1 complex. Receptor 2 exhibits an excellent enantioselective recognition ability toward the enantiomers of bis(tetrabutylammonium) dibenzoyl tartrate. 相似文献
7.
Jürgen O. Daiß 《Journal of organometallic chemistry》2005,690(3):678-684
A series of novel β-carbonylsilanes, with a silacyclohexane skeleton and additional C-functionalized organyl groups at the silicon atom, were synthesized, their reactivity was explored, and they were structurally characterized by multinuclear NMR spectroscopy. The aim of these investigations was to provide the basis for the development of novel silicon-based drugs containing a silacyclohexane skeleton, with a CH2C(O)R substituent and an additional C-functionalized organyl group at the silicon atom. 相似文献
8.
Yevhen M. Ivon Ivan V. Mazurenko Yuliya O. Kuchkovska Prof. Dr. Zoya V. Voitenko Dr. Oleksandr O. Grygorenko 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(41):18172-18178
Formyl MIDA boronate has been known to be an elusive type of acylboronate that has not been obtained to date. In this work, an approach to the one-pot preparation and chemical transformations of formyl MIDA boronate were developed to provide new types of α-functionalized organoboron compounds. Among them are acylboronate reagents which present boron-substituted analogues of ynones and β-dicarbonyl compounds. The developed synthetic procedures, utilizing formyl MIDA boronate, are tolerant to diverse functional groups, making this reagent an advantageous C1 building block for extending the scope of organoboron chemistry. 相似文献
9.
A new chiral fluorescent BINOL boronic acid 1 has been synthesized. The chiral recognition properties of 1 are drastically different from BINOL boronic acid c. Sensor 1 shows improved enantioselectivity as well as chemoselectivity toward sugar alcohols, such as d-sorbitol and d-mannitol.The enantioselectivity of sensor 1 toward d-sorbitol (KR/KS) is 1:35 (pH 9.0), and the chemoselectivity for d-sorbitol/d-mannitol is 20:1. 相似文献
10.
Rebecca M. Duke 《Tetrahedron letters》2010,51(41):5402-7844
The quinoxaline 1, possessing a 2,6-pyridyl-based amidothiourea moiety, with the view of forming a pre-organised molecular cleft, was developed as a fluorescent anion sensor. The sensing ability of 1 was evaluated in organic solution where both the ground and the excited state of 1 was affected upon recognition of anions such as acetate [as tetrabutylammonium salt (TBAAc) solution] at the amiodothiourea moieties in MeCN. The fluorescence of 1, with λmax at 477 nm, was, on all occasions quenched, upon anion recognition. Using TBAOH, we also show that the same anion-induced changes occurred; demonstrating that for this particular sensor, the anion-sensing takes place via a deprotonation mechanism. This anion-induced deprotonation event was further investigated by carrying out 1H NMR titrations on 1, using both AcO− and OH− in DMSO-d6. 相似文献
11.
Four cholate-based pyridinium compounds were synthesized and their binding abilities toward unmodified amino acids were investigated by UV spectroscopy and fluorescence emission spectroscopy. Studies revealed that the recognition process involved hydrogen bonding, electrostatic force, and π–π interaction. The receptor 4a was found to recognize l-tryptophan specifically, and the complex was studied by 1H NMR spectroscopy. The receptors 4b and 4c showed very little recognition ability toward l-tryptophan, indicating the important role of the benzyl group at pyridinium ring. 相似文献
12.
Yu Liu Ying-Wei Yang Yan Zhao Li Li Heng-Yi Zhang Shi-Zhao Kang 《Journal of inclusion phenomena and macrocyclic chemistry》2003,47(3-4):155-160
A novel bridged bis(β-cyclodextrin),m-phenylenediimino-bridged bis(6-imino-6-deoxy-β-cyclodextrin) (2), was synthesized by the reaction of m-phenylenediamine and 6-deoxy-6-formyl-β-cyclodextrin. The inclusion complexation behavior of the novel bridged bis(β-cyclodextrin) 2,as well as native β-cyclodextrin (1),p-phenylenediamino-bridged bis(6-amino-6-deoxy-β-cyclodextrin) (3) and 4,4'-bianilino-bridged bis(6-amino-6-deoxy-β-cyclodextrin) (4) with representative fluorescent dye molecules, i.e., acridine red (AR), neutral red (NR), Rhodamine B (RhB), ammonium 8-anilino-1-naphthalenesulfonate (ANS) and sodium 6-toluidino-2-naphthalenesulfonate (TNS), was investigated at 25 °C in aqueous phosphate buffer solution (pH 7.20) by means of fluorescence, and circular dichroism, as well as 2D NMR spectrometry. The spectrofluorometric titrations have been performed to calculate the complex stability constants (KS) and Gibbs free energy changes (Δ G°) for the stoichiometric 1 : 1 inclusion complexation of 1–4 with fluorescent dye molecules. The results obtained demonstrated that bis(β-cyclodextrin)s 2–4 showed much higher affinities toward these guest dyesthan native β-cyclodextrin 1. Typically, dimer 2 displayed the highest binding ability upon inclusion complexation with ANS, affording 35 times higher KS value than native β-cyclodextrin. The significantlyenhanced binding abilities of these bis(β-cyclodextrin)s are discussed from thebinding mode and viewpoints of size/shape-fit concept and multiple recognition mechanism. 相似文献
13.
Xue-Bin ShaoXi-Kui Jiang Xiao-Zhong WangZhan-Ting Li Shi-Zheng Zhu 《Tetrahedron》2003,59(26):4881-4889
A novel strapped porphyrin receptor Zn1, in which two electron-rich bis(p-phenylene)-34-crown ether-10 units are incorporated, has been designed and synthesized from the newly developed intermediate 7 for investigating new chemistry of molecular recognition. 1H NMR and UV-Vis studies revealed that Zn1 displays relatively weak binding abilities to neutral electron deficient naphthalene-1,8,4,5-tetracarboxydiimide (NDI) derivatives 13 (no simple complexing stoichiometry was observed), 19 (Ka=48(±5) M−1) and 30 (Ka=46(±5) M−1) in chloroform-d, strong binding ability to pyridine derivative 25, (Ka=1.5(±0.12)×103 M−1) in chloroform, moderately strong binding ability to tetracationic compound 35·4PF6 (Ka=475(±50) M−1) in acetone-d6, and very strong binding affinity to compound 22 (Ka=6.5(±0.7)×105 M−1), which consists of one pyridine and two NDI units, in chloroform. Remarkable cooperative effect of the intermolecular metal-ligand coordination and donor-acceptor interactions in complex Zn1·22 was observed by comparing the complexing behaviors between Zn1 and the appropriately designed guests. Complex Zn1·22 possesses an unique three-dimensional tri-site binding feature. For comparison, the complexing affinity of 1 toward compounds 13, 19, and 30 in chloroform-d and 35·4PF6 in acetone-d6 has also been investigated and the binding patterns in different complexes were explored. The results demonstrate that strapped porphyrin derivatives are ideal precursors for constructing new generation of three-dimensional multi-site artificial receptors for molecular recognition and host-guest chemistry. 相似文献
14.
A new unsymmetrical diarylethene derivative (1o) with rhodamine 6G as a functional group has been designed and synthesized. It displayed good physicochemical properties induced by lights and chemical stimuli. 1o could sensitively detect towards Cr3+ with a 1:1 stoichiometry, and exhibit an obviously fluorescence (from dark to light cyan) and color (from colorless to pink) changes during the recognition process. The limit of detection was determined to be 27?nM and 8.5?nM via UV/vis and fluorescence methods, respectively. More importantly, the resulting complex 1o-Cr3+ (1o') could be served as a potential fluorescent probe to selectively and sensitively recognize toward CO32?, the limit of detection was determined to be 0.88?μM and 0.26?μM via UV/vis and fluorescence methods, respectively. Moreover, the quenching of fluorescence intensity can reach 95% due to the perfect FRET processes between the excited open-ring rhodamine 6G moiety and the closed-ring diarylethene unit. 相似文献
15.
A 1,8-diphenylnaphthalene-based diamidine (1) ‘turn-on’ fluorescent probe for the detection of dicarboxylic acids has been designed and synthesized. The fluorescence spectra of the diamidine 1 with carboxylic acids that showed two different fluorescence bands, which corresponded to the amidinium-carboxylate (λem=410–430 nm) and amidinium (λem=440–470 nm as a broad band, which consisted from two peaks) formation, were confirmed by DOSY NMR and TD-DFT calculations. The complexation of diamidine 1 with dicarboxylic acids, which have sufficient distances between the two carboxylic groups for binding to the diamidine 1 (dicarboxylic acids 3, 4, and α,ω-dicarboxylic acids 6 (C6–C20)), showed the formation of 1:1 complexes (i.e., amidinium-carboxylate formation). On the other hand, for the complexation with monocarboxylic acids and dicarboxylic acids having insufficient distances between the two carboxylic groups (benzoic acid 5, acetic acid 7, and α,ω-dicarboxylic acids 6 (C3–C5)), formation of the amidinium (1·2H+) was observed. Relatively similar binding constants (10−5) for the complexation of the diamidine 1 with dicarboxylic acids 6, which depend on their chain length (strain), were observed due to the flexibility of the 1,8-diphenylnaphthalene unit. Additionally, for the complexation of the diamidine 1 with dicarboxylic acids, higher fluorescence quantum yields (Φfl: up to 80%) were observed when compared to the binding of the diamidine 2 (Φfl: up to 35%). 相似文献
16.
Masamichi Yamanaka Tomoe Nakagawa Ryohei Aoyama Tomohiko Nakamura 《Tetrahedron》2008,64(51):11558-11567
C3-Symmetry tris-urea low molecular weight gelator (LMWG) (1), which shows chemical stimuli responsible for a sol-gel phase transition, was divided into five regions. Based on the division, 22 derivatives were synthesized. The gelation ability of these derivatives was tested in nine organic solvents with a wide range of values for relative static permittivity (?r=47.2-1.89). Some derivatives showed a better performance as LMWGs than the original tris-urea LMWG (1). For example, the critical gelation concentration (CGC) in acetone was improved from 1.5 wt % to 0.5 wt % by changing the core substituent (18). Highly versatile LMWG for a variety of solvents was obtained by changing the linker moiety (23). Structural information to design tris-urea LMWGs is important to create rationally a functional supramolecular gel. 相似文献
17.
A series of new C2-symmetric chiral aza crown ether macrocycles 1–4 have been synthesized from (S)-3-aryloxy-1,2-propanediol and (S)-1,2-propanediol for the enantiomeric recognition of amino acid ester derivatives. These new macrocycles have been shown to be strong complexing agents for primary organic ammonium salts (with K up to 176.93 M?1 and ΔG° up to 12.81 kJ mol?1) by 1H NMR titration. These macrocyclic host exhibited enantioselective bonding toward the d-enantiomer of phenylalanine methyl ester hydrochloride with KD/KL up to 6.87 in CDCl3 with 0.25% CD3OD. 相似文献
18.
《Tetrahedron: Asymmetry》2005,16(8):1527-1534
Two novel types of chiral calix[4]arenes containing hydrazide and dansyl groups were synthesized and examined for their enantioselective recognition abilities by the fluorescence and 1H NMR spectra in CHCl3. The results indicate that both 4a and 4b have excellent enantioselectivities to the N-protected alanine or phenylalanine anions. 相似文献
19.
A new fluorescent imidazolium-based cholestane receptor 4 bearing a pyrene moiety was synthesized. The binding ability of 4 toward various dicarboxylic acids was examined by UV-vis and fluorescence spectroscopy. Receptor 4 showed the highest binding constant for oxalic acid among all the tested dicarboxylic acids (Ka = 5.06 × 104 M−1). Oxalic acid formed a complex with 4 with a 1:2 ratio in ethanol. 相似文献
20.
G.Attilio Ardizzoia S Brenna G LaMonica A Maspero N Masciocchi 《Journal of organometallic chemistry》2002,649(2):173-180
Three new molybdenum(0) complexes, [Mo(CO)3(Hpz)3] (1), [Mo(CO)2(Hpz)2(DMAD)2] (2), (DMAD=dimethyl acetylenedicarboxylate) and [Mo(CO)3(1-Me-imidazole)3] (3) were synthesized and characterized. Their activity and selectivity in alkyne cyclotrimerization and co-trimerization reactions was investigated. The molecular structures of 1 and 2 have been determined by unconventional powder and standard single-crystal diffraction methods, respectively. 1 consists of a pseudo-octahedral complex of C3 symmetry, with the ligands in fac disposition; complex 2, of idealized C2 symmetry, is obtained by substitution of one CO and one pyrazole in 1 by two DMAD ligands, and shows the rare trans configuration of π-bound acetylenic moieties. 相似文献