共查询到20条相似文献,搜索用时 15 毫秒
1.
Qian-ni Guo Cheng Zhong Yun-guo Lu Chuang Shi Zao-ying Li 《Journal of inclusion phenomena and macrocyclic chemistry》2012,72(1-2):79-88
Novel 2,3-bis(1H-pyrrol-2-yl)quinoxaline-functionalized hydrazones were prepared and characterized as new chemosensors for copper(II) ion. The binding properties of the compounds 4, 5, 6 and 7 for cations were examined by UV–vis, fluorescence spectroscopy, and linear sweep voltammetric experiments (LSV). The results indicate that a 1:1 stoichiometric complex is formed between compound 4 (or 5, 6, 7) and copper(II) ion, and the association constant is 1.3?×?105 M?1 for 4, 2.1?×?106 M?1 for 5, 4.1?×?105 M?1 for 6 and 8.0?×?105 M?1 for 7, respectively. The recognition mechanism between compound 4 (or 5, 6, 7) and metal ion was discussed based on their electrochemical properties, absorbance changes, and the fluorescence quenching effect when they interact with each other. Control experiments revealed that compound 4 (or 5, 6, 7) has a highly selective response to copper (II) ion. 相似文献
2.
Farukh Arjmand Mubashira Aziz Mala Chauhan 《Journal of inclusion phenomena and macrocyclic chemistry》2008,61(3-4):265-278
New water soluble Co(II) 1, Ni(II) 2 and Cu(II) 3 complexes of 4,15-bis(2-hydroxyethyl)-2,4,6,13,15,17-hexaazatricyclodocosane Co(II) were synthesized and characterized by various techniques, viz. elemental analysis, conductivity measurements, infrared, electronic, ESI-MS, 1H and 13C NMR spectroscopy. Molar conductance measurements in aqueous solution showed that complexes 1, 2 and 3 are ionic in nature. On the basis of spectroscopic data, a square planar geometry was assigned to the complexes involving four N-atoms of the two cyclohexane moieties. Interaction studies of 1 and 3 with CT-DNA were carried using UV/Visible absorption spectroscopy, fluorescence spectrophotometry, cyclic voltammetry and viscosity measurements. Absorption spectral traces reveal 27.7 and 23.3% hyperchromism for complexes 1 and 3, respectively indicative of strong binding to CT-DNA. These results were authenticated by fluorescence quenching experiments and viscosity measurements. The intrinsic binding constants K b of 1 and 3 are 2.94 × 104 and 2.71 × 104 M?1, respectively. Early transition metals show preference for O6 position while later ones copper and cobalt prefer N7 position of DNA base guanine. To validate this hypothesis, interaction studies of copper (II) and cobalt (II) complexes were carried out with 5′GMP, which revealed electrostatic interactions are more favored along with hydrogen bonding than coordinate covalent interaction to N7 position of guanine. 相似文献
3.
Tianzhi Yu Shuxia Yang Yuling Zhao Peng Zhang Zhe Lv Duowang Fan Zhongrong Geng 《Research on Chemical Intermediates》2012,38(1):215-222
Three coumarin derivatives, 7-hydroxy-3-(2-pyridyl)coumarin (HPC), 7-(4-(5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl)benzyloxy)-3-(2-pyridyl)coumarin (Ox-PC), and 7-(4-(9H-carbazol-9-yl)butoxy)-3-(2-pyridyl)coumarin (Cz-PC), were synthesized and characterized by elemental analysis, 1H NMR, FT-IR, and UV?Cvis absorption spectra. The fluorescence behaviors of the compounds in methanol solutions and solid states were investigated. HPC exhibits weak green emission, whereas Cz-PC and Ox-PC show strong blue emissions in dilute solutions. 相似文献
4.
V. B. Nazarov V. G. Avakyan M. V. Fomina A. I. Vedernikov M. V. Alfimov S. P. Gromov 《Russian Chemical Bulletin》2013,62(10):2150-2157
Electronic absorption and fluorescence spectroscopy showed that the addition of 2-hydroxypropyl cyclodextrin derivatives (HP-α-CD, HP-β-CD, and HP-γ-CD) to an aqueous solution of 4-(2-naphthyl)pyridinium perchlorate (2) results in its partial deprotonation and formation of an inclusion complex of 4-(2-naphthyl)pyridine (1) with the cavitand. The stoichiometry and stability of the inclusion complexes of compounds 1 and 2 and 1-methyl-4-(2-naphthyl)-pyridinium perchlorate (3) with cyclodextrins and their hydroxypropyl derivatives (logK = = 1.5–2.7) were studied by 1H NMR titration. Cyclodextrins with the neutral form 1 form more stable complexes than with ionic compounds 2 and 3. The protonation of the nitrogen atom of compound 2 in aqueous solutions can occur in both the ground and excited states, and the fluorescence spectrum exhibits only the band of the protonated form. Quantum chemical simulation of the deprotonation/protonation processes in an aqueous solution of compound 2 in the absence and presence of HP-β-CD was performed. A tendency for shifting the acid-base equilibrium towards the formation of deprotonated form 1 is observed upon the addition of 2-hydroxypropyl cyclodextrin derivatives to the solution. 相似文献
5.
The singlet and triplet excited state properties of a series of fullerene derivatives (C60) are compared to those of the corresponding heteroazafullerenes derivatives (C59N) by employing a variety of steady-state and time-resolved photophysical assays. The most far-reaching results infer that the C59N (2, 5) analogous of C60 (1, 4) are characterized by shorter singlet lifetimes (1.01/0.57 ns versus 1.80/1.75 ns) and weaker fluorescence quantum yields (1.6 × 10-4/2.1 × 10-4 versus 6.0 × 10-4/1.09 × 10-3). This general conclusion applies for the monoadduct series (1, 2) and also for the highly functionalized hexaadducts (4, 5). Similarly, higher singlet energies (1.89 eV (4) versus 1.79 eV (1)) come together with higher fluorescence quantum yields for the hexaadducts than for the monoadducts. 相似文献
6.
Zeliha Hayvalı Pınar Köksal 《Journal of inclusion phenomena and macrocyclic chemistry》2013,76(3-4):369-378
A series of new benzo-15-crown-5 derivatives (1–6) containing formyl and imine groups were prepared. New formyl crown ethers (1 and 2) were prepared by reaction of 4′,5′-bis(bromomethyl)benzo-15-crown-5 with 2-hydroxy-3-methoxybenzaldehyde (o-vanillin) and 2-hydroxy-5-methoxybenzaldehyde in the presence of NaOH. New Schiff bases (3–6) were synthesized by the condensation of corresponding aldehydes with 1,3-diaminopropane and 1,4-diaminobutane. Sodium and potassium complexes (1a–6a and 1b–6b) of the crown compounds forming crystalline complexes of 1:1 (Na+:ligand) and 1:2 (K+:ligand) stoichiometries were also synthesized. The structures of the aldehydes 1 and 2, imines 3–6 and complexes (1a–3a and 1b–3b) were confirmed on the basis of elemental analyses, IR, 1H- and 13C-NMR, and mass spectroscopy. 相似文献
7.
Three novel coordination polymers, {[Co(L)(SO4)(H2O)](CH3OH)}∞ (1), {[Cd(L)2(SiF6)](H2O)}∞ (2) and [Zn(L)(NO3)2]∞ (3), synthesized from 1,4-di(benzimidazole-1-yl)benzene (L), have been characterized by infrared spectroscopy, elemental analysis and single crystal X-ray diffraction. Compounds 1–3 exhibit different structures. Complex 1 has a 3-D diamond network containing 1-D CoII chains connected by SO 4 2? · anions; 2 has a 3-D-Po framework with 1-D porous channels along the c axis; and 3 has a 1-D zig-zag chain structure with a 2-D supramolecular network based on π-π interactions. The magnetic properties of 1 and the solid state fluorescence spectra of 2 and 3 have also been explored. 相似文献
8.
Caterina Fraschetti Antonello Filippi Maria Elisa Crestoni Claudio Villani Graziella Roselli Stefano Levi Mortera Maurizio Speranza 《Journal of the American Society for Mass Spectrometry》2012,23(10):1778-1785
The enantioselective interactions between chiral tetra-amidic receptors and nucleosides have been investigated by the ESI-IT-MS and ESI-FT-ICR-MS methodologies. Configurational effects on the CID fragmentation of diastereomeric [M H 2 ?H?A]?+ aggregates (A?=?2'-deoxycytidine dC, citarabine (ara-C) were found to be mostly offset by isotope effect in [S X 2 ?H?A]?+ (X?=?H, D) differently from the results obtained on the analogues (A?=?cytidine C and gemcitabine G). This result points the involvement of two different nucleoside/tetraamide isoforms. The structural differences of the [M H 2 ?H?A]?+ (A?=?C and G) complexes vs. the [M H 2 ?H?A]?+ (dC and ara-C) ones is fully confirmed by the kinetics of their uptake of the 2-aminobutane enantiomers, measured by FT-ICR mass spectrometry. Indeed, uptake of the 2-aminobutane enantiomers by [M H n ?H?A]?+ (n?=?1,2; A?=?dC and ara-C) complexes is reversible, while that by [M H n ?H?A]?+ (n?=?1,2; A?=?C and G) is not. The most encouraging result concerning the measured fragmentation and kinetic differences between C and ara-C, that are just epimers, indicates the possibility to subtly modulate the non-covalent drug/receptor interactions, through the electronic properties of the 2'-substituent on the nucleoside furanose ring, and furthermore on its three-dimensional position. 相似文献
9.
Duygu Sahin Zeliha Hayvali 《Journal of inclusion phenomena and macrocyclic chemistry》2012,72(3-4):289-297
New benzo-15-crown-5 derivatives containing nitro, amine and imine groups were prepared. Nitro compound (1) was prepared after the reaction?4′,5′-bis(bromethyl)benzo-15-crown-5 and o-nitrophenol in the presence of NaOH. After reduction process by using hydrazine hydrate and Pd/C amine compound (2) was formed. New crown ether imine compounds (3–5) were synthesized by the condensation of corresponding crown ether diamine (2) with salicylaldehyde derivatives. Sodium complexes of the crown compounds (1a–5a) form crystalline 1:1 (Na+: ligand) complexes with sodium perchlorate. Nickel(II) complexes (3b–5b) with 1:1 (Ni2+:ligand) stoichiometries were also been synthesized from the Schiff bases (3–5). The results indicated that the Schiff base ligands coordinated through the azomethine nitrogen and phenolic oxygen. The extraction ability of compounds (1, 3, 4 and 5) were also evaluated in chloroform by using several alkali and transition metal picrates such as Li+, Na+, K+, Cr3+, Mn2+, Ni2+, Cu2+, Zn2+ and Pb2+. 相似文献
10.
The reactions of 3(5)-(4-methoxyphenyl)-5(3)-phenyl-1H-pyrazole (L 1 ) with nitric acid and 5-(4-benzyloxyphenyl)-3-(furan-2-yl)-1H-pyrazole(L 2 ) with hydrochloric acid produced [HL 1 · NO3] (Salt-1) and [HL 2 · Cl] (Salt-2). The structures of Salt-1 and Salt-2 were determined by single crystal X-diffraction. In Salt-1, HL 1 showed [2 + 2] binding of NO3 ? ions in the solid state to form dimer architecture with R 1 2 (4) and R 4 4 (14) graph sets. An anion directed one-dimensional anion-assisted helical chain with active participation of the chloride ion and protonated pyrazole via N–H···Cl hydrogen bonding in Salt-2. In addition, the protonated HL 2 molecules interacted with each other through weak C–H···π interactions resulting in the formation of another one-dimensional helical chain. 相似文献
11.
Winfried Wendelin Hans-Wolfgang Schramm Andreas Blasi-Rabassa 《Monatshefte für Chemie / Chemical Monthly》1985,116(3):385-400
Guanidine and phenylguanidine react with phenylhexadienone1b and 1,5-diaryl-2,4-pentadien-1-ones1c–k respectively (via unstable dihydropyrimidines of type2 as intermediates) to 4-methyl- and 4-aryl-6-styryl-2-pyrimidinamines3b–j and N2-phenyl-2-pyrimidinamines7c, k. Efforts to stabilize the intermediates2 by introduction of electron-withdrawing substituents (compare2,3) were not successful. Similarly, thiourea reacts with diphenylpentadienone1c to afford (via8c) 4-phenyl-6-phenethylpyrimidinethione9c. Action of guanidine on 1,3,5-triphenylpentadienone101 and on the 5-(3-chlorophenyl) analogue10m under decomposition of the ketones yields 4,6-diphenyl-and 4-(3-chlorophenyl)-6-phenyl-2-pyrimidineamine (121 andm), respectively. The formation of12m proves that acetophenone splits off from101,m during the reactions. However, heating of thiourea with10m in sodium butylate/butanol gives the expected 4,6-diphenyl-4-styryldihydropyrimidinethione13m. The reaction of thiourea with triphenylpentadienone101 is taking an atypical course: Addition of thiourea to the δ- and β-carbon atom of101 affords 2-(4,6-diphenyl-2-thioxohexahydro-4-pyrimidinyl)acetophenone (141); the conformation of the latter was deduced from1H-NMR data. 相似文献
12.
Helmut Paulus Karl Schlögl Walter Weissensteiner 《Monatshefte für Chemie / Chemical Monthly》1983,114(6-7):799-808
Starting from1-(dimethylaminomethyl)-2-iodo-ferrocene (3) [2.2](1,2)ferrocenophane (2) was prepared in an 8-step synthesis with 17% overall yield. Both from the oxoderivative12 and the ferrocenophane2 puretrans-isomers (12b and2b, resp.) were obtained; the former (12b) was reduced to a separable mixture ofexo andendo 1-hydroxy-ferrocenophanes13a andb, resp. (~ 3:7), the configurations of which were assigned by the LIS-method. X-ray crystal structure analysis of2b revealed a centrosymmetrical chair conformation. From1H- and13C-NMR spectra both for2b and for the hydroxyderivatives13 a rigidexo-exo chair conformation was deduced. 相似文献
13.
Zsolt Rapi Péter Bakó György Keglevich Péter Baranyai Miklós Kubinyi Olívia Varga 《Journal of inclusion phenomena and macrocyclic chemistry》2014,80(3-4):253-261
Two new chiral glucopyranoside-based crown ethers incorporating acridine fluorescent signalling units, 15-membered ligand 1 and 21-membered ligand 2 were synthesized. Their complexation properties toward alkali and alkali earth metal ions, and their enantioselectivity towards chiral ammonium salts were studied by absorption and fluorescence spectroscopic experiments. Macrocycle 1 formed 1:1 complexes with all the metal ions selected and the stability constants were low (lg K < 2.3). The cavity-size of 2 allowed only the complexaton of organic ammonium ions. Crown 2 showed chiral discrimination in case of all the four ammonium salts used as model guest compounds; the highest enantioselectivity (K(R)/K(S) ~3) was observed for the enantiomers of phenylethyl ammonium perchlorate. Ligand 2 forms much more stable complexes with metal ions; the highest stability constant was obtained for the Ca2+ complex (lg K = 6.15). The coordination of metal ions by ligand 2 was accompanied by marked fluorescence enhancement, whereas the binding of ammonium ions by the same species resulted in significant fluorescence quenching. 相似文献
14.
Sabir H. Mashraqui Sukeerthi Kumar Dhaval Vashi 《Journal of inclusion phenomena and macrocyclic chemistry》2004,48(3-4):125-130
Crown ethers 1–4, encompassing a photoemittive benzothiazole chromophore have been synthesised using standard protocols. Alkali metal picrate extraction profiles reveal that compared to the known crown ethers, benzothiazole benzo-15-crown-5 1 and benzothiazole dibenzo-18-crown-6 3 exhibit relatively higher % extraction for K+ than Na+ ions. The UV-visible and fluorescence spectra of 1–4, in comparison to their neutral forms were found to be red shifted on protonation due to enhanced intramolecular charge transfer transition. The ortho-substituted benzothiazole crowns 2–4 showed higher Stokes shifts compared to the para analog 1 in the presence of CF3CO2H, presumably due to H-bond assisted conformational restriction. No changes were noticeable in the absorption spectra in the presence of alkali metal ions. Even, fluorescence properties of 1–4 were not found to be drastically perturbed by these ions. While 1 exhibited slight quenching at alkali metal ion concentration over 10-folds with respect to that of 1, interestingly, 2–4 showed a slight enhancement of fluorescent intensity at least up to 10-fold concentration of metal ions over those of 2–4. Further increase of metal ion concentrations produces quenching effects. This behavior has been tentatively explained by invoking electrostatic interaction between these cations and the benzothiazole nitrogen ligand. 相似文献
15.
Two ratiometric fluorescence and colorimetric anion sensors were designed and synthesized according to simple Schiff base reaction. Two compounds 1 and 2 were characterized by ESI–MS, elemental analyses and 1H NMR. The sensors could give fast and visible color changes from yellow to red upon presence of the strong basic anions such as acetate ion. In particular, two compounds exhibited marked blue shifts (about 136 nm) in their emission spectra, when interacting with anions. Accordingly, the compounds 1 and 2 could act as real-time ratiometric fluorescence and colorimetric sensors for anions. 相似文献
16.
Dirk M. Guldi Michele Maggini Gianfranco Scorrano Maurizio Prato 《Research on Chemical Intermediates》1997,23(6):561-573
A systematic fluorescence and flash photolytic investigation of a series of covalently linked fullerene / ferrocene based donor-bridge-acceptor dyads is reported as a function of the nature of the bridge between the donor site and acceptor site. The fluorescence of the investigated dyads 2 (Φrel = 0.17 × 10?4, 3 (Φrel = 0.78 × 10?4), 4 (Φrel = 1.5 × 10?4), 5 (Φrel = 0.7 × 10?4), and 6 (Φrel = 2.9 × 10?4) were substantially quenched, relative to N-methyl fulleropyrrolidine (1) (Φrel = 6.0 × 10?4). Photolysis of N-methyl fulleropyrrolidine (1) in toluene revealed formation of the excited singlet state which was followed by a rapid intersystem crossing to the excited triplet state. On the other hand, the fate of the excited singlet state of 2, 3, 4, 5, and 6 was found to be governed by rapid intramolecular quenching, with rate constants of 28×109 s?1, 6.9×109 s?1, and 3.4×109 s?1, 14×109 s?1, 2.3×109 s?1 respectively. The electron transfer process and the charge separation were confirmed by monitoring the characteristic π-radical anion bands at λmax = 400 and 1055 nm in degassed benzonitrile with τ1/2 = 1.8 μs (3) and 2.5 μs (4). 相似文献
17.
Excited state intramolecular hydrogen atom transfer of phenylethynyl-substituted 2′-hydroxychalcones
Satomi Tasaki Atsuya Momotake Yoko Kanna Tatsuo Arai 《Research on Chemical Intermediates》2013,39(1):61-72
(E)-1-[2-Hydroxy-4-(phenylethynyl)phenyl]-3-[4-(phenylethynyl)phenyl]prop-2-en-1-one (1), (E)-1-[2-hydroxy-4-(phenylethynyl)phenyl]-3-phenylprop-2-en-1-one (2), and (E)-1-(2-hydroxyphenyl)-3-[4-(phenylethynyl)phenyl]prop-2-en-1-one (3), which belong to a new class of 2′-hydroxychalcones with phenylethynyl group(s) at the para position of the phenyl ring, were synthesized, and their photochemical properties were investigated. The lowest energy absorption band of 1 peaks at a longer wavelength (383 nm) with a much larger molar extinction coefficient (5.0 × 104 M ?1 cm?1) than that of the parent 2′-hydroxychalcone (2′HC) (2.0 × 104 M ?1 cm?1 at 318 nm). Upon photoexcitation, all three compounds underwent excited-state intramolecular hydrogen atom transfer (ESIHT) to produce an excited tautomer that emitted fluorescence with a large Stokes shift in the longer wavelength region at 600–700 nm. The quantum yield of the tautomer fluorescence of 1 was not high at 298 K (Φ f = 9.1 × 10?5), but was highest among 2′HC and its analogues. The Φ f values of 1–3 increased 10–30 fold upon reducing the temperature from 298 to 77 K. 相似文献
18.
Amita Bist Seung Joo Cho Nisar Ahmed 《Journal of inclusion phenomena and macrocyclic chemistry》2013,77(1-4):75-81
A highly sensitive fluorescent turn-on probe specific for mercury ion has been developed on the basis of mercury ion-promoted hydrolysis of a pyrene-1-carbaldehyde hydrazone (1). The chemical conversion of 1, catalyzed by Hg2+ ions, was studied by using UV, fluorescence and 1H NMR spectroscopy, which clearly showed the conversion of 1 to highly fluorescent compound 1-pyrenecarboxaldehyde (2). 相似文献
19.
Li-Wei Cao Yang Hu Si-Liu Liang Cong Li Jian-Xin Meng 《Journal of Analytical Chemistry》2013,68(7):639-645
A sensitive and efficient analytical method for gabapentin (GBP) in human serum based on capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection has been established. 6-Oxy-(N-succinimidyl acetate)-9-(2′-methoxycarbonyl) fluorescein (SAMF), a new synthesized fluorescent reagent, was used for precolumn derivatization of the non-fluorescent drug in serum. γ-Aminobutyric acid (GABA) was used as an internal standard (I.S.). The best derivative condition was obtained in phosphate buffer (pH 8) at room temperature for 10 min. Optimal separation and detection were obtained with a background electrolyte (BGE) of 3.5 × 10?2 M phosphate buffer (pH 5.5) and laser-induced fluorescence detection excited at 473 nm. The method developed for GBP was linear over the concentration range of 4.0 × 10?9 to 4.0 × 10-7 M. The concentration limit of detection was 2.0 × 10?10 M (signal-to-noise ratio = 3). The sensitive method was used for the determination of GBP in serum samples. 相似文献
20.
Abdelwaheb Hamdi Mohamed Habib Noomen Rym Abidi A. Rim Woo Jeong Hwan Cho Yang Kim 《Journal of inclusion phenomena and macrocyclic chemistry》2011,71(3-4):287-291
The synthesis and complexation properties of three new derivatives, one spirobiscalix[4]azacrown (1) and two calix[4]azacrown (2 and 3), are reported. Complexation studies of the three ligands toward transition and heavy metal cations have been carried out and monitored by UV absorption spectrophotometry in acetonitrile. Mononuclear complexes were detected for all complexes, whereas binuclear species (M2L) were also formed in the case of ligand 1 with Cu2+ and Pb2+. The extraction properties of 1, 2 and 3 toward Cu2+, Zn2+, Pb2+, Ag2+ and Cd2+ are also reported. The results showed that complexation is the main factor affecting extraction with ligands 2 and 3, while with ligand 1 it is not. 相似文献