Yuanzhi Song

Facile One-Pot, Multicomponent Synthesis of Pyridines Under Microwave Irradiation

Abstract A series of 2-amino-6-(2-oxo-2H-chromen-3-yl)-4-pyridine-3-carbo-nitriles were synthesized by the one-pot, multicomponent reaction of 3-acetyl-coumarin, aromatic aldehydes, malononitrile, and ammonium acetate in acetic acid under microwave irradiation. The reactions were completed in 10–13 min with 61–86% yields, were environmental benign, and had easy workup. Their structures were confirmed by 1H NMR, IR, and MS spectra and elemental analysis.

The electrochemical behavior of dopamine at glassy carbon electrode modified by Nafion multiwalled carbon nanotubes

DFT (B3LY/6-31G (d, p) and B3LYP/cc-PVDZ) calculations are performed for deoxidized dopamine (DA(R)) and its oxidized form (DA(O)). The electrochemistry of dopamine (DA) was studied by cyclic voltammetry (CV) at a glassy carbon electrode modified by Nafion multiwalled carbon nanotubes (MWNTs) in phosphate buffers at pH 5.4, showing that the standard electrode potential of a half reaction for DA(O), H+/DA(R) is 0.74 V. This experimental standard electrode potential of the half reaction is consistent with those of 0.65 and 0.69 V calculated using the energies of solvation and the sum of the electronic and thermal free energies of DA(R) and DA(O). The frontier orbital theory and Mulliken charges of molecules explain the electrochemical behavior of CV at a modified electrode well. The effects of oxygen on DA(R) in blood and drug are also discussed according to equilibrium theory. The modified electrode was successful for determination of the content of pharmaceutical DA.

Theoretical study on the geometry and vibration of 1-{6-(4-Chlorophenyl)-1-[(6-chloropyridin-3-yl)methyl]-2-[(6-chloropyridin-3-yl)methylsulfanyl]-4-methyl-1,6-dihydropyrimidin-5-yl}ethanone

The solid phase FT-IR and FT-Raman spectra of 1-[6-(4-chlorophenyl)-1-[(6-chloropyridin-3-yl)methyl]-2-[(6-chloropyridin-3-yl)methylsulfanyl]-4-methyl-1,6-dihydropyrimidin-5-yl]ethanone (C25H21Cl3N4OS) were recorded in the region 4000-400 and 3500-100cm(-1), respectively. The vibrational spectra have been computed using density functional theory (B3LYP) and ab initio molecular orbital calculation (HF) with 6-31G(d, p) basis sets. A close agreement was achieved between the observed and calculated frequency by employing normal coordinate calculations. The observed and simulated spectra were found to be well comparable.

Electrochemical synthesis of gold nanoparticles on the surface of multi-walled carbon nanotubes with glassy carbon electrode and their application

Gold nanoparticles on the surface of multi-walled carbon nanotubes with glassy carbon electrode were prepared using electrochemical synthesis method. The thin films of gold Nanoparticles/multi-walled carbon nanotubes were characterized by scanning electron microscopy, powder X-ray diffraction, and cyclic voltammetry. Electrochemical behavior of adrenaline hydrochloride at gold nanoparticles/multi-walled carbon nanotube modified glassy carbon electrode was investigated. A simple, sensitive, and inexpensive method for determination of adrenaline hydrochloride was proposed.

Gold-nanoparticle on the surface of L-cysteine modified gold electrode and its application

A sensor based on gold nanoparticle on the surface of L-cysteine modified gold electrode is prepared. Electrochemical behavior of dopamine hydrochloride is investigated. The linear relation between peak current of dopamine hydrochloride and scan speed in the range of 10 to 1000 mV s−1 indicates that a diffusion-adsorption controls the process. The linearity range is 1.05 × 10−5–7.38 × 10−4 M with detection limit of 1.05 × 10−6 M. The recoveries were in the range from 99.8 to 101.5% with relative standard deviations of 1.3 ∼ 2.3% (n = 6). The modified electrode under ambient conditions over a period of 2 weeks has an excellent repeatability and reproducibility.

Experimental and theoretical study on the synthesis of gold nanoparticles using ceftriaxone as a stabilizing reagent for and its catalysis for dopamine

Electrochemical synthesis of gold nanoparticles on the surface of glassy carbon electrode and preparation of GNPs in aqueous solution using ceftriaxone as an innocuous stabilizing reagent were proposed. The gold nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, infrared spectrometry, UV spectrophotometry, powder X-ray diffraction, and cyclic voltammetry. The catalysis of gold nanoparticles on the glassy carbon electrode for dopamine was demonstrated. The results indicate that the modified electrode has an excellent repeatability and reproducibility. The relationship between the molecular structure and the dispersion of GNPs on the surface of GCE as well as the catalysis of GNPs for dopamine was discussed.

Synthesis and theoretical studies on the vibration of a novel (3,4-disfluoro)phenylquione

A novel (3,4-disfluoro)phenylquione (2F-PQ) was synthesized through the reaction of 3,4-Difluoroaniline and 1,4-benzoquinone. Its structure was verified by (1)H NMR, FTIR and Raman spectra. The ground-state geometries were optimized by using density functional theory (DFT) at B3LYP/6-311G+(d,p), B3PW91/6-311G+(d,p) and MPB3PW91/6-311G+(d,p) level without symmetry constrains, respectively. The predicted FTIR and Raman spectra scaled by factor are well consistent with experimental spectra.

Theoretical and experimental studies of the electrochemistry of p-aminophenol on a golden electrode

The geometric parameters, vibrational frequencies, and thermochemical values of p-quinonimine (p-AQ) and p-aminophenol (p-AP) were computed ab initio (IIF) and by the density functional theory (DFT) method with the 6-31G(d, p) basis set. Cyclic voltammetry with a golden electrode of p-AP solutions in phosphate buffers at pH 7.30 showed that the standard electrode potential of half reaction for p-QI and p-AP was 0.728 V. The standard electrode potentials of half reactions for p-QI and p-AP were calculated using the free energies and solvation energies of p-QI, p-AP, p-benzoquinone (p-BQ), and hydroquinone (p-HQ). The results showed that the standard electrode potential of half reaction for p-QI and p-AP was 0.743 V at the B3LYP/6-31G(d, p) level and 0.755 V at the HF/6-31G(d, p) level. The standard electrode potentials computed at the B3LYP/6-31G(d, p) and HF/6-31G(d, p) levels were close to their experimental values.

Experimental and theoretical study of the electrochemical synthesis of silver nanoparticles using ampicillin as a stabilizing reagent

Electrochemical synthesis of silver nanoparticles on the surface of glassy carbon electrode using ampicillin as a stabilizing reagent are prepared. The silver nanoparticles are characterized by scanning electron microscopy, cyclic voltammetry, and infrared spectrometry. The electrochemical catalysis of AgNPs for sodium sulfide was demonstrated. The relationship between the molecular structure of ampicillin and the dispersion of GNPs on the surface of GCE as well as the catalysis of GNPs for sodium sulfide was discussed.

Synthesis of gold nanoparticles on the surface of pyrolytic graphite using penicillin as a stabilizing reagent and the catalytic oxidation of α-naphthylamine

Electrochemical synthesis of gold nanoparticles on the surface of pyrolytic graphite using penicillin as a stabilizing reagent was proposed. The gold nanoparticles were characterized by scanning electron microscopy, cyclic voltammetry, IR spectra, UV spectra, and powder X-ray diffraction spectra. The electro-chemical catalysis of penicillin for α-naphthylamine was demonstrated.