6290-05-7Relevant articles and documents
Iminodiacetic acid functionalized polypyrrole modified electrode as Pb(II) sensor: Synthesis and DPASV studies
Joseph, Alex,Subramanian, Sankaran,Ramamurthy, Praveen C.,Sampath, Srinivasan,Kumar, R. Vasant,Schwandt, Carsten
, p. 557 - 563 (2014)
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.
Protein surface recognition by synthetic receptors: A route to novel submicromolar inhibitors for α-chymotrypsin
Park, Hyung Soon,Lin, Qing,Hamilton, Andrew D.
, p. 8 - 13 (1999)
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.
Anion effects in Cu-crosslinked palindromic artificial tripeptides with pendant Bpy ligands
Gallagher, Joy A.,Levine, Lauren A.,Williams, Mary Elizabeth
, p. 4168 - 4174 (2011)
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.
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
De Bettencourt-Dias, Ana,Fetto, Natalie R.,Monteiro, Jorge H. S. K.,Tucker, Matthew J.
supporting information, p. 3193 - 3199 (2020/03/19)
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.
Synthesis and Hydrolysis of 4-Chloro-PyMTA and 4-Iodo-PyMTA Esters and Their Oxidative Degradation with Cu(I/II) and Oxygen
Qi, Mian,Hülsmann, Miriam,Godt, Adelheid
supporting information, p. 3773 - 3784 (2016/10/30)
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.
