Bilge Taner

Effect of Au and Au@Ag core–shell nanoparticles on the SERS of bridging organic molecules

Gold nanoparticles (AuNPs) with about 6 nm size were produced and stabilized with mercaptopropionic acid (MPA) film to produce a monolayer protected cluster (MPC) of AuS(CH(2))(2)COOH. 4-Aminothiophenol (ATP) molecules were introduced to the activated carboxylic acid ends of the film surrounding the AuNPs to produce AuS(CH(2))(2)CONHPhSH MPC. These modified AuNPs were again self-assembled with Au@Ag core-shell bimetallic nanoparticles via the -SH groups to produce an organic bridge between Au and Au@Ag metallic nanoparticles. An unusually strong enhancement of the Raman signals was observed and assigned to the plasmon coupling between the AuNPs and Au@Ag NPs bridged assembly. Formation of AuS(CH(2))(2)COOH and AuS(CH(2))(2)CONHPhSH clusters and AuS(CH(2))(2)CONHPhS(Au@Ag) assembly is confirmed by UV-Vis, reflection-absorption IR spectroscopy (RAIRS) and X-ray photoelectron spectroscopy (XPS), as well as by TEM analysis. The SERS activity of the AuNPs and Au@Ag NPs was tested using the HS(CH(2))(2)CONHPhSH molecule as a probe to compare the effectiveness of monometallic and bimetallic systems. SERS spectra show that Au@Ag bimetallic nanoparticles are very effective SERS-active substrates.

The example of calix[4]pyrrole derivative containing Bodipy unit: fluorometric and colorimetric sensor for F- ion.

A novel chemosensor based on calix[4]pyrrole derivative modified by Bodipy unit has been synthesized, and its complexes with various anions were investigated. The results show that the receptors can selectively recognize biologically important fluoride ions. The binding affinity for fluoride ions was investigated by naked-eye color change, absorption, emission, proton nuclear magnetic resonance spectroscopy. The addition of fluoride ions to an acetonitrile solution of chemosensor can result in an obvious color change (brownish yellow color to straw yellow). The stoichiometries between the receptor and fluoride were determined from the molar ratio plots using the UV-visible spectra, which showed evident 1:1. The proton nuclear magnetic resonance spectral data supported the fluoride anion recognition with the disappearance of the amino proton peaks.

Synthesis of a new colorimetric receptor based on calix[4]pyrrole binding oxime for selective recognition of fluoride ions

A colorimetric anion sensor α-meso-heptaethylcalix[4]pyrrole-meso-3-aminophenyl-p-nitrobenzaldoxime was synthesised and characterised by various spectroscopic techniques. Anion-binding studies were carried out using UV–vis, and 1H NMR titrations, revealing that the receptor exhibits selective recognition towards F− over other anions. The selectivity for F− among the halides is attributed mainly to the hydrogen bond interaction of the receptor with F− . Receptor showed colour change from colourless to yellow in the presence of tetrabutylammonium fluoride with 1:2 stoichiometry. Cyclic voltammetry studies, carried out in CH3CN, provided evidence of an anion-dependent electrochemical response with F− ion. This response was particularly dramatic in the case of receptor after the addition of ∼1 equiv. of F− ion.

Synthesis, characterization, thermal, and redox properties of a vic-dioxime and its metal complexes

A new vic-dioxime ligand containing benzophenone hydrazone units, N′-(benzophenone hydrazone)glyoxime [LH2] has been prepared from benzophenone hydrazone and anti-chloroglyoxime in absolute ethanol. Mononuclear nickel(II), cobalt(II), copper(II), zinc(II), and cadmium(II) complexes were also synthesized. Ligand and complexes were characterized by elemental analyses, FT-IR, 1H NMR, and 13C NMR spectroscopy, magnetic moments, and DTA/TG techniques. On the basis of the magnetic and spectral evidences a square-planar geometry for Ni(II) and Cu(II) complexes, tetrahedral for Cd(II) and Zn(II) complexes, and octahedral for Co(II) complex were proposed. Redox behaviors of ligand and its complexes were also investigated by cyclic voltammetry at the glassy carbon electrode.

Synthesis and complexation of two new phenylaminoglyoxime ligands

Two new soluble phenylaminoglyoxime ligands, 4-isopropylanilinephenylglyoxime (L1H2), 4-benzylpiperidinephenylglyoxime (L2H2), were prepared by reacting 4-isopropylaniline and 4-benzylpiperidine with chlorophenylglyoxime. Mononuclear nickel(II), cobalt(II), copper(II), zinc(II), and cadmium(II) complexes with these ligands were synthesized. On the basis of the magnetic and spectral evidence a square-planar geometry for Ni(II) and Cu(II) complexes, a tedrahedral geometry for Cd(II) and Zn(II) complexes and octahedral geometry for Co(II) complexes are proposed. These compounds were elucidated by elemental analysis, IR, UV-Vis, and magnetic moments. The ligands were additionally characterized by 1H NMR and 13C NMR spectra.

Preparation and Spectral and Biological Investigation of vic-Dioxime Ligands Containing Piperazine Moiety and Their Mononuclear Transition-Metal Complexes

Abstract Two vic-dioxime ligands, N-(4-benzylpiperazine-1-yl) p-tolylglyoxime (L1H2) and N,N′-bis(4-benzylpiperazine-1-yl) glyoxime (L2H2), containing piperazine moieties were synthesized, and their Ni(II), Cu(II), Co(II) and Zn(II) complexes were obtained. The ligands were characterized by elemental analysis, Fourier transform–infrared (FT-IR), ultraviolet–visible NMR (1H, 13C, and heteronuclear multiple-bond correlation), and electrospray ionization (ESI) mass spectrometry. The isolated complexes were characterized by a combination of elemental analysis, IR, UV-vis, and ESI mass spectrometry and in the case of Ni(II) and Zn(II) complexes by 1H and 13C NMR spectroscopy. The electrochemical behaviors of the ligands and their complexes were studied by cyclic voltammetry (CV) in dimethylsulfoxide solution containing tetrabutylammoniumtetrafluoroborate (TBATFB). The antibacterial activity was also studied against S. aureus ATCC 25923, S. aureus ATCC 29213, S. mutans RSHM 676, E. faecalis ATCC 29212, E. coli ATCC 25922, and P. aeruginosa ATCC 27853. The antimicrobial test results indicated that all the compounds have good antibacterial activity against P. auriginosa ATCC 27853 bacteria and were as effective as ampicilin. [Supplementary materials are available for this article. Go to the publishers online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.] GRAPHICAL ABSTRACT

Synthesis and characterization of new (E,E)-dioximes and their divalent metal complexes

Two new soluble vic-dioxime ligands, 4-isopropylanilineglyoxime (L1H2) and 4-benzylpiperidineglyoxime (L2H2) were prepared by reacting 4-isopropylaniline and 4-benzylpiperidine with anti-chloroglyoxime. Ten metal complexes were obtanied by reacting both ligands with Cu(II),Ni(II),Co(II), Zn(II), and Cd(II) cations. The ligands and their metal complexes were elucidated by elemental analysis, IR, UV-vis, 1H NMR, and 13C NMR and also magnetic moments of the complexes were determined.

Thermal Degradation Behaviour of Ni(II) Complex of 3,4-Methylenedioxaphenylaminoglyoxime

Thermal degradation behaviour of the Ni(II) complex of 3,4-methylenedioxaphenylaminoglyoxime was investigated by TG, DTA, and DTG at a heating rate of 10°C min−1 under dinitrogen. The acquired experimental data shows that the complex is thermally stable up to 541 K. The pyrolytic decomposition process occurs by melting metal complex and metal oxide remains as final product. The energies of the reactions involved and the mechanism of decomposition at each stage have been examined. The values of kinetic parameters such as activation energy (), preexponential factor () and thermodynamic parameters such as enthalpy (), entropy (), and Gibbs free energy () are also evaluated.