- Iminodiacetic acid functionalized polypyrrole modified electrode as Pb(II) sensor: Synthesis and DPASV studies
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An electrochemical lead ion sensor has been developed by modification of carbon paste electrode (CPE) using polypyrrole functionalized with iminodiacetic acid (IDA-PPy) containing carboxyl group. The electrochemical response of Pb2+ion on the IDA-PPy modified CPE has been evaluated and the controling parameters have been optimized using differential pulse anodic stripping voltammetry (DPASV). The IDA-PPy modified CPE shows a linear correlation for Pb2+concentrations in the range of 1 × 10-6to 5 × 10-9M and the lower detection limit of Pb2+has been found to be 9.6 × 10-9M concentration. Other tested metal ions, namely Cu2+, Cd2+, Co2+, Hg2+, Ni2+and Zn2+, do not exhibit any voltammetric stripping response below 1 × 10-7M concentration. However, the Pb2+response is affected in the presence of molar equivalents or higher concentrations of Cu2+, Cd2+and Co2+ions in binary systems with Pb2+, consequent to their ability to bind with iminodiacetic acid, while Hg2+, Ni2+and Zn2+do not interfere at all. A good correlation has been observed between the lead concentrations as analyzed by DPASV using IDA-PPy modified CPE and atomic absorption spectrophotometry for a lead containing industrial effluent sample.
- Joseph, Alex,Subramanian, Sankaran,Ramamurthy, Praveen C.,Sampath, Srinivasan,Kumar, R. Vasant,Schwandt, Carsten
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- Aminoquinoline-based fluorescent probe for detection of Cu2 + and hydrogen sulfide
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Diethyl 2,2′-(2-oxo-2-(quinolin-8-ylamino)ethylazanediyl) diacetate (DOQED), an aminoquinoline-based fluorescent probe, was synthesized, and successfully applied in detection of Cu2 + and S2 - in an aqueous buffered solution. The emission signal of DOQED was selectively quenched by Cu2 +, and was exclusively recovered by subsequent addition of S2 -. The formation of a [Cu(DOQED)]2 + complex was confirmed by X-ray crystallography.
- Zhang, Liangwei,Sun, Jinyu,Liu, Shudi,Cui, Xuemei,Li, Weishuang,Fang, Jianguo
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- Protein surface recognition by synthetic receptors: A route to novel submicromolar inhibitors for α-chymotrypsin
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A family of synthetic receptors for protein surface recognition has been prepared. The receptors are based on a design in which four peptide loops are arrayed around a central calilx[4]arene core. By varying the sequence of the loop regions a range of differently functionalized receptor surfaces approximately 450 ?2 in area can be prepared. From this family we have identified potent inhibitors of chymotrypsin that function by binding to the surface of the protein. The most potent of these (1) shows slow binding kinetics in an analogous manner to several of the natural protein proteinase inhibitors. Detailed kinetic analysis showed 1 to be a competitive inhibitor with K(i) and K(i)* values of 0.81 and 0.11 μM, respectively.
- Park, Hyung Soon,Lin, Qing,Hamilton, Andrew D.
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- Synthesis of triazolyl anthracene as a selective fluorescent chemosensor for the Cu(II) ion
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The Cu(I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC) has been used to synthesize an anthracene-based fluorescent compound that undergoes strong fluorescence quenching in the presence of Cu(II). Fluorescence studies indicate that the compound forms a 1:1 complex and can be used to quantitatively determine micromolar concentrations of Cu(II) in aqueous solution.
- Varazo, Kris,Xie, Fang,Gulledge, Dana,Wang, Qian
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- Anion effects in Cu-crosslinked palindromic artificial tripeptides with pendant Bpy ligands
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An artificial peptide with three pendant bipyridine (bpy) ligands on a palindromic backbone was designed and used to make multimetallic assemblies. The tripeptide is synthesized by addition of ligand-substituted aminoethylglycine monomers to both ends of a bpy-substituted diacid. The tripeptide was treated with CuII acetate, tetrafluoroborate, and nitrate salts, and the chelation stoichiometry was confirmed in spectrophotometric titrations. NMR spectroscopy, mass spectrometry, and analytical HPLC separations confirm the identity and purity of the product, which is a tripeptide duplex with three CuII coordinative crosslinks. UV/Vis absorbance and EPR spectroscopy were used to assess the geometry of the metal complexes and examine the effects of coordinative anions on the coordination geometry about the Cu centers. We find that the distorted square-planar geometry in the Cu duplex shifts to a tetrahedral geometry upon addition of I- and that counteranions can be used to tune the interaction between metal complexes in multimetallic assemblies.
- Gallagher, Joy A.,Levine, Lauren A.,Williams, Mary Elizabeth
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- Photocytotoxicity of Oligothienyl-Functionalized Chelates That Sensitize LnIII Luminescence and Generate 1O2
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Three new compounds containing a heptadentate lanthanide (LnIII) ion chelator functionalized with oligothiophenes, nThept(COOH)4 (n=1, 2, or 3), were isolated. Their LnIII complexes not only display the characteristic metal-centered emission in the visible or near-infrared (NIR) but also generate singlet oxygen (1O2). Luminescence efficiencies (?Ln) for [Eu1Thept(COO)4]? and [Eu2Thept(COO)4]? are ?Eu=3 percent and 0.5 percent in TRIS buffer and 33 percent and 3 percent in 95 percent ethanol, respectively. 3Thept(COO)44? does not sensitize EuIII emission due to its low-lying triplet state. Near infra-red (NIR) luminescence is observed for all NIR-emitting LnIII and ligands with efficiencies of ?Yb=0.002 percent, 0.005 percent and 0.04 percent for [YbnThept(COO)4]? (n=1, 2, or 3), and ?Nd=0.0007 percent, 0.002 percent and 0.02 percent for [NdnThept(COO)4]? (n=1, 2, or 3) in TRIS buffer. In 95 percent ethanol, quantum yields of NIR luminescence increase and are ?Yb=0.5 percent, 0.31 percent and 0.05 percent for [YbnThept(COO)4]? (n=1, 2, or 3), and ?Nd=0.40 percent, 0.45 percent and 0.12 percent for [NdnThept(COO)4]? (n=1, 2, or 3). All complexes are capable of generating 1O2 in 95 percent ethanol with ?1Ο2 efficiencies which range from 2 percent to 29 percent. These complexes are toxic to HeLa cells when irradiated with UV light (λexc=365 nm) for two minutes. IC50 values for the LnIII complexes are in the range 15.2–16.2 μm; the most potent compound is [Nd2Thept(COO)4]?. The cell death mechanisms are further explored using an Annexin V—propidium iodide assay which suggests that cell death occurs through both apoptosis and necrosis.
- Johnson, Katherine R.,Lombardi, Vincent C.,de Bettencourt-Dias, Ana
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supporting information
p. 12060 - 12066
(2020/08/21)
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- Luminescent Carbazole-Based EuIII and YbIII Complexes with a High Two-Photon Absorption Cross-Section Enable Viscosity Sensing in the Visible and near IR with One- And Two-Photon Excitation
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The newly synthesized EuIII and YbIII complexes with the new carbazole-based ligands CPAD2- and CPAP4- display the characteristic long-lived metal-centered emission upon one- and two-photon excitation. The EuIII complexes show the expected narrow emission bands in the red region, with emission lifetimes between 0.382 and 1.464 ms and quantum yields between 2.7% and 35.8%, while the YbIII complexes show the expected emission in the NIR region, with emission lifetimes between 0.52 and 37.86 μs and quantum yields between 0.028% and 1.12%. Two-photon absorption cross sections (σ2PA) as high as 857 GM were measured for the two ligands. The complexes showed a strong dependence of the one- and two-photon sensitized emission intensity on solvent viscosity in the range of 0.5-200 cP in the visible and NIR region.
- De Bettencourt-Dias, Ana,Fetto, Natalie R.,Monteiro, Jorge H. S. K.,Tucker, Matthew J.
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supporting information
p. 3193 - 3199
(2020/03/19)
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- Copper-induced ammonia N-H functionalization
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The activation of ammonia has been achieved with the aid of the TpMsCu core (TpMs = hydrotris(3-mesityl-pyrazolyl)borate). Complexes of the general composition TpMsCu(amine) (1-4) including the ammonia adduct TpMsCu(NH3) (1) have been synthesized and fully spectroscopical- and structurally characterized. Coordinated ammonia in 1 has been reacted with Ph3CPF6 yielding TpMsCu(NH2CPh3) (5) as a result of N-H cleavage and N-C bond formation. In a parallel manner the catalytic functionalization of ammonia with ethyl diazoacetate leading to glycinate derivatives has been developed with TpMsCu(THF) as the catalyst, in the first example of this transformation with ammonia and a copper-based system.
- álvarez, María,álvarez, Eleuterio,Fructos, Manuel R.,Urbano, Juan,Pérez, Pedro J.
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p. 14628 - 14633
(2016/10/03)
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- Synthesis and Hydrolysis of 4-Chloro-PyMTA and 4-Iodo-PyMTA Esters and Their Oxidative Degradation with Cu(I/II) and Oxygen
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We disclose the syntheses of ethyl and tert-butyl esters of 4-chloro-PyMTA and 4-iodo-PyMTA from the commercially available chelidamic acid monohydrate in 39-67% overall yield. Additionally, ester hydrolyses with aqueous NaOH (ethyl esters) or trifluoroacetic acid (tert-butyl esters) are reported. The resulting materials contain 4-halo-PyMTA in mixture with partially deprotonated or partially protonated 4-halo-PyMTA. The ligand content expressed as the content of the common structural motifs of the present species, namely [PyMTA - 4 H+4- (basic hydrolysis) and PyMTA (acidic hydrolysis), was determined to be 90-94 wt % by1H NMR spectroscopy using maleic acid as an internal standard. The tert-butyl esters were easily hydrolyzed with aqueous alkali hydroxide, with a decreasing rate in the series NaOH, KOH, LiOH. This finding indicates a Lewis acid assisted ester cleavage with the Na+ ion fitting best to the multidentate ligand. Unexpectedly, PyMTA esters are incompatible with Cu(I/II) salts in the presence of oxygen. Under these conditions, one of the two aminomethyl groups is converted into a formyl group. This reaction not only limits the application of Cu(I/II)-catalyzed reactions but also necessitates trapping of any copper ions (e.g., with a metal ion scavenger) before the material is exposed to oxygen.
- Qi, Mian,Hülsmann, Miriam,Godt, Adelheid
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supporting information
p. 3773 - 3784
(2016/10/30)
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- Animal and vegetable oils or prior method for preparing heavy metal chelating agent (by machine translation)
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The invention relates to a land oil (catering waste oil) and animal and vegetable oils containing fat chain preparing method of heavy metal chelating agent, comprising the following steps: alkaline hydrolysis of fat obtain fatty acid mixture; preparing acyl halide; and diglycolamidic dioester condensation; selectively hydrolyzed ester is fatty chain containing heavy metal chelating agent mixture. Total yield of all steps can be up to 80%. The qualitative experiments show that the chelating ability, the preparation containing according to the method the C16 [...] C20 fatty chain amide diethyla acid chelating agent on the heavy metal salt Cd (NO 3) 2 4H 2 O, HgCl 2, MnCl 2 4H 2 O, CoCl 2 6H 2 O, NiCl 2 6H 2 O has strong chelating performance. The Pb (OAc) 2, CrCl 3 chelating property is relatively weak. The method for preparing the chelating agent can be used for "extraction" from the soil in the heavy metal ion. Furthermore, because the chelating agent may be a mixture, can utilize waste oil as raw material preparation, so that the can into the popularization of the technology of the, kitchen waste is reduced to the pressure of the environment. (by machine translation)
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Paragraph 0018
(2018/02/04)
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- 3,4-Dialkoxypyrrole for the Formation of Bioinspired Rose Petal-like Substrates with High Water Adhesion
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Self-organization is commonly present in nature and can lead to the formation of surface structures with different wettabilities. Indeed, in nature superhydrophobic (low water adhesion) and parahydrophobic (high water adhesion) properties exist, such as in lotus leaves and red roses, respectively. The aim of this work is to prepare parahydrophobic properties by electrodeposition. For this, pyrrole derivatives with two alkoxy groups of various lengths (from 1 to 12) were synthesized in 8 steps by adapting a method developed by Merz et al. We show that the alkyl chain length has a huge influence on the polymer solubility and as a consequence on the surface morphology and hydrophobicity. Moreover, the alkyl chain length should be at least greater than eight carbons in order to obtain parahydrophobic properties. The properties are also controlled by the electrolyte nature. These materials can be used for many potential applications in water harvesting and transportation and separation membranes.
- Mortier, Claudio,Darmanin, Thierry,Guittard, Frédéric
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p. 12476 - 12487
(2016/12/07)
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- Ultraviolet radiation absorbing polymers
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The present invention includes an ultraviolet radiation absorbing polymer composition that includes polymers containing a UV-chromophore, as described in the specification and as claimed the reaction product of a monoglyceride and a poly-acid monomer containing a UV-chromophore.
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Page/Page column 9; 10; 11
(2016/11/09)
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- Monitoring the kinetics of ion-dependent protein folding by time-resolved NMR spectroscopy at atomic resolution
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The kinetics of protein refolding have been monitored by time-resolved NMR spectroscopy. It is shown that refolding of metal binding proteins can be induced by photolysis of photo labile ion chelators, the subsequent release of Ca2+ ions can induce protein folding, and the changes in resonance positions can be monitored by time-resolved NMR spectroscopy. The feasibility of the approach is demonstrated by characterizing the refolding of α-lactalbumin, or protein containing a Ca2+ binding site, unfolded in 4 M urea at pH 7 in the absence of Ca2+. The refolding kinetics of the methyl groups of residues Leu15 and Val21 in the core of the protein have been determined to be mono-exponential with rates of 0.28 s-1 and 0.23 s-1, respectively at 300 K.
- Kuehn, Till,Schwalbe, Harald
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p. 6169 - 6174
(2007/10/03)
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- 52. Influence of Chelating Groups on the Luminescence Properties of Europium(III) and Terbium(III) Chelates in the 2,2'-Bipyridine Series
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Eight different 2,2'-bipyridine derivatives, i.e. 2, 5, 8, 10, 12, 13, 15, and 19 (Schemes 1 and 2), were prepared to study the influence of the chelating groups on the luminescence properties of their EuIII and TbIII chelates.According to our luminescence results, 2,2'-(methylenenitrilo)bis(acetic acid) as well as (methylenenitrilo)bis(methylphosphonic acid) in 6- and 6'-position of 2,2'-bipyridine is a suitable group when developing luminescent markers for bioaffinity assays based on time-resolved luminescence measurement.
- Mukkala, Veli-Matti,Kwiatkowski, Marek,Kankare, Jouko,Takalo, Harri
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p. 893 - 899
(2007/10/02)
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- Synthesis of photolabile chelators for multivalent cations
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A method of synthesizing photolabile chelators as EDTA and EGTA derivatives to be used in caging multivalent cations is disclosed. The chelators chelate the cations forming non-biologically active compounds. The chelated compounds can then be localized in or near biological systems. Upon irradiation, the chelated compound cleaves with the subsequent cleaved remainders having a substantially lower affinity for the chelated cation. Large amounts of cation are thus rapidly released and the effect of such concentration jumps on the biological system can be accurately studied.
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- A New Class of Photolabile Chelators for the Rapid Release of Divalent Cations: Generation of Caged Ca and Caged Mg
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The synthesis of 2-nitro-4,5-dimethoxyphenyl derivatives of EGTA and EDTA is reported.These tetracarboxylate chelators are designed for the rapid photochemically initiated release of divalent cations in intact physiological systems.The key step in the synthesis is the use of high-pressure synthetic technology for the construction of the tertiary amine moiety of both types of chelator.
- Ellis-Davies, G.C.R.,Kaplan, J.H.
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p. 1966 - 1969
(2007/10/02)
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- Trialkylamine/sulfur dioxide catalyzed sulfenylation of carbamates
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An improved process for sulfenylating carbofuran in the presence of a solvent and acid acceptor with a disubstituted aminosulfenyl halide, in which the reaction is conducted in the presence of a catalytic amount of a complex of a lower alkylamine and sulfur dioxide, is disclosed and exemplified.
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