We report results of the studies relating to the fabrication and characterization of a conducting polymer based molecularly imprinted para-nitrophenol (PNP) sensor. A water pollutant, para-nitrophenol is electrochemically imprinted with polyvinyl sulphonic acid (PVSA) doped polyaniline onto indium tin oxide (ITO) glass substrate. This PNP imprinted electrode (PNPI-PANI-PVSA/ITO) prepared via chronopotentiometric polymerization and over-oxidation is characterized by Fourier transform infra-red spectroscopy (FT-IR), UV–visible (UV–vis) spectroscopy, contact angle (CA), scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies. The response studies of PNPI-PANI-PVSA/ITO electrode carried out using DPV reveal a lower detection limit of 1 × 10−3 mM, improved sensitivity as 1.5 × 10−3 A mM−1 and stability of 45 days. The PNPI-PANI-PVSA/ITO electrode shows good precision with relative standard deviation of 2.1% and good reproducibility with standard deviation of 3.78%. 相似文献
Oxidation of some hydrocarbons dissolved in acetic acid by cerium(IV) sulphate at 100 °C in the presence of traces of iridium(III) chloride (catalyst-substrate 1:56818 to 151515) in the solution phase resulted in good to excellent yields of corresponding carbonyl compounds. In the cases of cyclohexane and benzene, 44% and 51.8% yields of corresponding carbonyl compounds were obtained, whereas in other cases, yield ranged from 34.9 to 99.8%. Yield decreased when reactions were performed in a microwave oven by adsorbing reactants (except acetic acid) on alumina. Decrease in the yield was probably due to the high temperature generated during the course of the reaction, resulting in the loss of organics from evaporation. Conditions were optimized for the highest yields under ambient conditions. 相似文献
Vinyl sulphides find a substantial application in organic synthesis.2 The synthetic utility of heter cyclic vinyl sulphides due to the ease in extension of heterocyclic ring3 should be more versatile, Here, we report the synthesis of isoquinolinyl vinyl sulphides from dihydrothiazolo [2, 3-a] isoquinolinium cations, depicting another use of heterocycles in organic synthesis.4相似文献
Oxidation of structurally diverse 2-arylbenzothiazolines to give the corresponding 2-arylbenzothiazoles has been carried out in benzene using dimethyldichlorosilane and trimethylchlorosilane. Short reaction times, mild reaction conditions, easy and quick isolation of the products, and excellent yields are the main advantages of this procedure. 相似文献
Enzyme “hexachlorocyclohexane (HCH) dehydrochlorinase LinA” mediates first step of aerobic microbial degradation of a chlorinated insecticide γ-HCH. The archetypal LinA-type1 consists of 156 amino acids that include a directly repeated hexapeptide motif GIHFAP at positions 141–146 and 148–153. Analysis of a series of LinA mutants, containing none, one, two, or three units of this repeated motif revealed that two units, as present in wild-type LinA, are required for its optimal activity and stability. Moreover, the presence of a bend in its secondary structure due to a proline residue that precedes the distal repeated unit contributes to enhanced LinA activity. 相似文献
Conjugation of a hydrophobic poly(2‐oxazoline) bearing tertiary amide groups along its backbone with a short single stranded nucleotide sequence results in an amphiphilic comb/graft copolymer, which organizes in fibrils upon direct dissolution in water. Supported by circular dichroism, atomic force microscopy, transmission electron microscopy, and scattering data, fibrils are formed through inter‐ and intramolecular hydrogen bonding between hydrogen accepting amide groups along the polymer backbone and hydrogen donating nucleic acid grafts leading to the formation of hollow tubes.
A self-assembled monolayer (SAM) of thiol modified chitosan (SH-CHIT), with thioglycolic acid (TGA) as a modifier to bestow thiol groups, has been prepared onto gold (Au)-coated glass plates for fabrication of the nucleic acid biosensor. The chemical modification of CHIT via TGA has been evidenced by Fourier transform infrared spectroscopy (FT-IR) studies, and the biocompatibility studies reveal that CHIT retains its biocompatible nature after chemical modification. The electrochemical studies conducted onto SH-CHIT/Au electrode reveal that thiol modification in CHIT amino end enhances the electrochemical behavior indicating that it may be attributed to delocalization of electrons in CHIT skeleton that participates in the resonance process. The carboxyl group modified end of DNA probe has been immobilized onto SH-CHIT/Au electrode using N-ethyl-N′-(3-dimethylaminopropyl)carbodimide (EDC) and N-hydroxysuccinimide (NHS) chemistry for detection of complementary, one-base mismatch and non-complementary sequence using electrochemical and optical studies for Mycobacterium tuberculosis detection. It has been found that DNA-SH-CHIT/Au bioelectrode can specifically detect 0.01 μM of target DNA concentration with sensitivity of 1.69?×?10?6 A μM?1. 相似文献
We have fabricated an immunosensor based on carbon nanotubes and chitosan (CNT-CH) composite for detection of low density lipoprotein (LDL) molecules via electrochemical impedance technique. The CNT-CH composite deposited on indium tin oxide (ITO)-coated glass electrode has been used to covalently interact with anti-apolipoprotein B (antibody: AAB) via a co-entrapment method. The biofunctionalization of AAB on carboxylated CNT-CH surface has been confirmed by Fourier transform infrared spectroscopic and electron microscopic studies. The covalent functionalization of antibody on transducer surface reveals higher stability and reproducibility of the fabricated immunosensor. Electrochemical properties of the AAB/CNT-CH/ITO electrode have been investigated using cyclic voltammetric and impedimetric techniques. The impedimetric response of the AAB/CNT-CH/ITO immunoelectrode shows a high sensitivity of 0.953?Ω/(mg/dL)/cm2 in a detection range of 0–120 mg/dL and low detection limit of 12.5 mg/dL with a regression coefficient of 0.996. The observed low value of association constant (0.34 M–1s–1) indicates high affinity of AAB/CNT-CH/ITO immunoelectrode towards LDL molecules. This fabricated immunosensor allows quantitative estimation of LDL concentration with distinguishable variation in the impedance signal. 相似文献
NH-Functional 1H-1,3-benzazaphospholes 1a–1c and o-chloranil (tetrachloro-o-benzoquinone - TCBQ) undergo rapid [1+4]-cycloaddition in a 1:2 molar ratio to give 2a – 2c as high-melting zwitterionic σ6λ5-phosphorus compounds. In the case of 2a the yield is high (rel. to TCBQ) even if the reactants were used in a 1:0.5 molar ratio. For the 2-tert-butyl-substituted compounds 2b and 2c the yields were significantly lower, in part by unidentified byproducts. Addition of excess TCBQ to crude 2c containing unconverted 1c did not increase but strongly decrease the amount of 2c . Crystallization and XRD analysis led to detection of a minor side or consecutive product 3c , formally corresponding to P=C bond cleavage and [1+4] cycloaddition of three equivalents TCBQ, two at the phosphinidene and one at the carbene end. NMR spectroscopic data of 2a – 2c including conclusive 13C data for 2a give evidence of the structures of the new compounds. 相似文献
The synthesis and characterization of the complexes of Cu(I), Ag(I), Cu(II), and Co(II) ions with 1,2,5-selenadiazolopyridine (psd) is reported. The following complexes have been prepared: [Cu(2)(psd)(3)(CH(3)CN)(2)](2+)2(PF(6)(-)); [(CuCl)(2)(psd)(3)]; [Cu(2)(psd)(6)](2+)2(ClO(4))(-); [Ag(2)(psd)(2)](2+)2(NO(3))(-); [Ag(2)(psd)(2)](2+)2(CF(3)COO)(-); [Cu(psd)(2)(H(2)O)(3)](2+)2(ClO(4))(-)·(psd)(2); [Cu(psd)(4)(H(2)O)](2+)2(ClO(4))(-)·(CHCl(3)); [Cu(psd)(2)(H(2)O)(3)](2+)2(NO(3))(-)·(H(2)O)·(psd)(2), and [Co(psd)(2)(H(2)O)(4)](2+)2(ClO(4))(-)·(psd)(2). The electronic structure of ligand psd, in particular the bond order of Se-N bonds, has been probed by X-ray diffraction, (77)Se NMR, and computational studies. A detailed analysis of the crystal structures of the ligand and the complexes revealed interesting supramolecular assembly. The assembly was further facilitated by the presence of neutral ligands for some complexes (Cu(II) and Co(II)). The molecular structure of the ligand showed that it was present as a dimer in the solid state where the monomers were linked by strong secondary bonding Se···N interactions. The crystal structures of Cu(I) and Ag(I) complexes revealed the dinuclear nature with characteristic metallophilic interactions [M···M] (M = Cu, Ag), while the Cu(II) and Co(II) complexes were mononuclear. The presence of M···M interactions has been further probed by Atoms in Molecules (AIM) calculations. The paramagnetic Cu(II) and Co(II) complexes have been characterized by UV-vis, ESI spectroscopy, and room temperature magnetic measurements. 相似文献