• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.719-725
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• 1998

Tridentate Schiff base ligands were prepared by the reactions of salicylaldehyde and 2-hydroxy-1-naphthaldehyde with 2-aminophenol and 2-amino-p-cresol. And then Cu(II) complexes of those ligands were synthesized. The structures and properties of ligands and their complexes were studied by elemental analysis, $^1H$-NMR, IR, UV-visible spectra, and thermogravimetric analysis. The mole ratio of Schiff base to the metal of complexes was found to be 1:1. Cu(II) complexes were contemplated to be four-coordinated square planar configuration containing one water molecule. The redox process of ligands and complexes in DMSO solution containing 0.1 M TBAP as a supporting electrolyte was investigated by cyclic voltammetry and differential pulse voltammetry with glassy carbon electrode. The redox process of the tridentate Schiff base ligands was totally irreversible. The redox process of Cu(II) complexes was quasi-reversible and diffusion-controlled as one electron by one step process Cu(II)/Cu(I). The reduction potentials of the Cu(II) complexes shifted in the positive direction in the order of [Cu(II)(HNIPC)($H_2O$)]>[Cu(II)(HNIP)($H_2O$)]>[Cu(II)(SIP)($H_2O$)]>[Cu(II)(SIPC)($H_2O$)].

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.850-858
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• 2010

The electronic absorption spectra of five Schiff bases derived from 2-hydroxy-1-naphthaldehyde with glycine, alanine, leucine, valine and phenylalanine have been measured in various solvents. The observed bands were assigned to the proper electronic transitions and compared with the predicted transitions at the semiempirical level of theory. The calculated equilibrium constants are in agreement with the experimental results, predicting the existence of all studied compounds predominantly or completely in keto-imine tautomerism. On the other hand, a correlation between $\nu\;(cm^{-1})$ (main frequency of each compound) and the well known solvent parameters $E_T$ (30), $\varepsilon_T$, $\pi^*$ been made. Furthermore, the acid dissociation constants, $pK_a$, were determined by using three different spectrophotometric methods.

• Journal of Environmental Science International
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• v.22 no.10
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• pp.1273-1278
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• 2013

Novel rhodamine 6G fluorescent chemosensors 1 and 2 for the detection of transition metal cations were synthesized through the condensation of rhodamine 6G ethylenediamine with each of 2-hydroxy-1-naphthaldehyde and 2,6-pyridinedicarbaldehyde, respectively. 1 and 2 were characterized using $^{13}C$ NMR, $^1H$ NMR and mass spectroscopy. Fluorometric and colorimetric measurements involving various metal ions revealed the ring opening of the rhodamine 6G spirocycle framework. In the absence of metal cations, 2 was colorless and non-fluorescent, whereas the addition of metal cations ($Hg^{2+}$ and others) changed the color to pink, accompanied by the appearance of an orange fluorescence. The chemosensors exhibited high selectivity for $Hg^{2+}$ over other divalent first-row transition metals. The complexes of $Hg^{2+}$ with 1 and 2 were successfully isolated. A huge enhancement in the fluorescence for both one- and two-photon excitations makes these compounds suitable candidates to be used for fluorescent labeling of biological systems.

• Analytical Science and Technology
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• v.12 no.6
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• pp.498-503
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• 1999

Co(II), Ni(II), and Cu(II) complexes with tetradentate schiff base-$NOTDH_2$, were synthesized. The structures of these complexes were characterized by elemental analysis, IR, UV-visible, NMR spectra, and thermogravimetric analysis. The mole ratio of schiff base($NOTDH_2$) to the metal(II) at complexes was found to be 1:1. Cu(II) complexes were four-coordinated configuration, while Co(II) and Ni(II) complexes were hexacoordinated configuration containing two water molecules and all complexes were non-ionic compounds.