• Analytical Science and Technology
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• v.24 no.6
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• pp.451-459
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• 2011

Eight coordinated terbium(III) complexes, tris (2-pyrazinecarboxylato)(phenanthroline) terbium(III) [$Tb(pzc)_3$(phen)], tris (5-methyl-2-pyrazinecarboxylato) (phenanthroline) terbium(III) [$Tb(mpzc)_3$(phen)] and tris(2-picolinato) (phenanthroline) terbium(III) [$Tb(pic)_3$(phen)], have been synthesized and characterized by Fourier transform infrared (FT-IR), UV-Visible and X-ray photoelectron spectroscopy. Photoluminescence (PL) spectroscopy shows that these complexes emitted strong green luminescence. When powder samples of the $Tb^{3+}$ complexes are examined using time-resolved spectroscopic analysis, the luminescence lifetimes are found to be 0.87 ms and 1.0 ms, respectively. Thermogravimetric analysis reveals the terbium complexes to have good thermal stability up to $333-379^{\circ}C$. Cyclic voltammetry shows that HOMO-LUMO energy gap of the $Tb^{3+}$ complexes ranges from 4.26~4.41 eV. These values are similar to those obtained from the UV-visible spectra. Overall, the synthesized $Tb^{3+}$ complexes may be useful advanced materials for green light emitting devices.

• Journal of the Korean Chemical Society
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• v.62 no.5
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• pp.372-376
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• 2018

A 1D-coordination polymer of $1D-\{Cu({\mu}-picolinato)_2\}$ $\{Hakimi,\;2012\;\sharp73\}_n$ (1), was prepared by the reactions between 2-(2-(pyridin-2-yl)oxazolidin-3-yl)ethanol (AEPC) ligand and $CuCl_2$ or $CuBr_2$. The product was characterized by elemental analysis, UV-Vis, FT-IR spectroscopy and single-crystal X-ray diffraction. The X-ray analysis results revealed that the AEPC ligand, after reactions with the copper(II) chloride or bromide, gives the same product - $1D-\{Cu({\mu}-picolinato)_2\}_n$ (1). The coordination modes for various picolinate-based ligands were extracted from the Cambridge Structural Database (CSD). In the crystal structure of 1, the copper atom has a $CuN_2O_4$ environment and octahedral geometry, which is distorted by elongation of the axial bond lengths due to the Jahn-Teller effect.

• Journal of the Korean Chemical Society
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• v.34 no.1
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• pp.85-90
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• 1990

The inertness of eight-coordinate tetrakis(picolinato)tungsten(IV) complex has been investigated by spectroscopic method in nonpolar solvent at 60$^{\circ}C$, 75$^{\circ}C$, 90$^{\circ}C$, 120$^{\circ}C$, and reflux condition. Until 2 days, showed the inertness whether existance of oxygen or not. After 2 days, showed the oxidation of W(IV) complex much more rapidly than substitution, which had $k_{obs}(sec^{-1}) {\varpropto} 1/[ligand]^2$. On sealing the sample under Ar gas, showed the inertness until 50 days, which had $k_{obs}(sec^{-1}) = 8.8{\times} 10^{-7}$. The$^1H$-NMR peak of $H_6$ in complex was diminished, otherwise that of free ligand was grown up. This result indicated that this complex was very inert.