• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2213-2216
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• 2009

A novel carbazole functionalized bis-$\beta$-diketone type organic ligand, 1,1′-(2,6-bispyridyl)bis-3-(9-ethylcarbazole- 3-yl)-1,3-propanedione ($H_2L$) and its corresponding lanthanide complexes $Eu_2(L)_3\;and\;Tb_2(L)_3$ were successfully prepared. The ligand and complexes were characterized in detail based on FT-IR spectra, $^1H$ NMR and elemental analysis. The observed UV-Vis absorption and photoluminescence properties of the complexes were investigated, it shows that the Eu(III) and Tb(III) ions can be sensitized efficiently by the ligand ($H_2L$) to some extent, in particular, the complex $Tb_2(L)_3$ exhibits a more excellent luminescence property than the Eu(III) complex. Meanwhile, the introduction of the carbazole moiety can enlarge the $\Pi$-conjugated system of the ligand and enhance the luminescent intensity of the complexes. The results show that the complexes would be used as excellent luminescent materials.

• Bulletin of the Korean Chemical Society
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• v.24 no.10
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• pp.1521-1524
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• 2003

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.711-718
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• 2017

Silver nanoparticles were attached by chemical reduction after synthesizing a porous PVK-CTA complex. The PVK-CTA complex was synthesized by polymerizing N-vinylcarbazole in a CTA-chloroform solution using iron(III) chloride as an oxidizing agent and a honeycomb-pattern with uniformly formed macropores was formed by applying steam to the complex surface soaked with a volatile solvent under humid conditions. Using TTF as a reducing agent and PVP as a dispersant, silver nanoparticles were attached on the Honeycomb-pattern complex surface through chemical reduction. The formation of the complex was confirmed by FT-IR and UV-Vis spectrometry, and the degree of thermal decomposition of the complexes was analyzed after N-vinylcarbazole was polymerized by varying its concentration. The uniformity of the pores on the composite surface and the dispersibility of the attached silver nanoparticles were investigated by SEM. The dispersibility of the silver nanoparticles was also analyzed by varying the concentrations of reducing agent and dispersant and precursor.

• Journal of the Korean Chemical Society
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• v.58 no.6
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• pp.681-685
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• 2014

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1367-1370
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• 2012

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.634-640
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• 2005

The reaction of cis-[Cr([14]-decane)(OH$_2)_2]^+$ ([14]-decane = rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-teraazacyclotetradecane) with auxiliary ligands {$L_a$ = citrate(cit)} leads to a new dimeric complex cis-[{Cr([14]-decane)($\mu$-cit)}$_2](ClO_4)_2$. This binuclear complex has been structurally characterized by a combination of elemental analysis, conductivity, IR and Vis spectroscopy, mass spectrometry, and X-ray crystallography. Analysis of the crystal structure of cis-[{Cr([14]-decane)($\mu$-cit)})($_2]^+$ reveals that each chromium has a distorted octahedral coordination environment and citrato ligands are monodentate to the two chromium atoms via the carboxyl groups. For dimeric complex the bridging geometry is as follows: Cr$\ldots$Cr = 7.361 $\AA$; Cr-O(average) = 1.958 (8) $\AA$; Cr-N range = 2.108 (9)-2.147(9) $\AA$; N(1)-Cr-N(3) (equatorial position) = 98.0(4)$^{\circ}$; N(2)-Cr-N(4) (axial position) = 166.4(4)$^{\circ}$; O(1)-Cr-N(2) = 98.1(4)$^{\circ}$; O(3)-Cr-N(4) = 96.6(3)$^{\circ}$; O(1)-Cr-O(3) = 90.4$^{\circ}$. The FAB mass spectrum of the dimeric complex displays peak due to the molecular ions cis-[{Cr([14]-decane)($\mu$-cit)})($_2]^+$ at m/z 1053.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2609-2615
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• 2013

A series of fluorene-carbazole copolymers containing the pendant phosphor chromophore $Ir(absn)_2(acac)$ (absn: 2-(1-naphthyl)benzothiazole; acac: acetylacetone) were designed and synthesized via Yamamoto coupling. In the film state, these copolymers exhibited absorption and emission peaks at approximately 389 and 426 nm, respectively, which originated from the fluorene backbone. However, in electroluminescent (EL) devices, a significantly red-shifted emission at approximately 611 nm was observed, which was attributed to the pendant iridium(III) complex. Using these copolymers as a single emission layer, polymer light-emitting devices with ITO/PEDOT:PSS/polymer:DNTPD/TmPyPb/LiF/Al configurations exhibited a saturated red emission at 611 nm. The attached iridium(III) complex had a significant effect on the EL performance. A maximum luminous efficiency of 0.85 cd/A, maximum external quantum efficiency of 0.77, maximum power efficiency of 0.48 lm/W, and maximum luminance of 883 $cd/m^2$ were achieved from a device fabricated with the copolymer containing the iridium(III) complex in a 2% molar ratio.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2754-2758
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• 2009

Three novel phosphorescent 2-phenylpyridine-based iridium(III) complexes, $[(ppy)_2Ir(P\^{}N)]PF6\;(1),\;[(dfppy)_2Ir(P\^{}N)]PF_6$ (2), and $[(dfmppy)_2 Ir(P\^{}N)]PF6$ (3), where $P\^{}N$ = 2-[(diphenylphosphino)methyl]pyridine (dppmp), were synthesized and characterized. The absorption, photoluminescence, cyclic voltammetry and thermal stability of the complexes were investigated. The complexes showed bright blue luminescences at wavelengths of 448 $\sim$ 500 nm at room temperature in $CHCl_3$ and revealed that the $\pi$-acceptor ability of the phosphorous atom in the ancillary dppmp ligand plays an important role in tuning emission color resulting in a blue-shift emission. The single crystal structure of $[(dfmppy))_2Ir(P\^N)]PF_6$ was determined using X-ray crystallography. The iridium metal center adopts a distorted octahedral structure coordinated to two dfmppy and one dppmp ligand, showing cis C-C and trans N-N chelate dispositions. There is a $\pi-\pi$ overlap between π electrons delocalized in the difluorophenyl rings.

• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.432-436
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• 1994

Monomeric rhodium and iridium-diaryltetrazene complexes $Cp^*$M(RNN=NNR)($Cp^*$=1,2,3,4,5-pentamethylcyclope ntadienyl; M=Rh, Ir; R=Ph, 4-tolyl) have been synthesized from [$Cp^*MCl_2]_2$(M=Rh, Ir) and 2 equiv. of $[Li(THF)_x]_2(RN_4$R) in benzene. We have determined the crystal structure of (${\eta}^5$-pentamethylcyclopentadienyl)diphenyltetrazene iridium by using graphite-monochromated Mo-$K_a$ radiation. The compound was crystallized in the monoclinic space group $P2_{1/c}$ with a=13.781(3), b=9.035(l), c=17.699(3) ${\AA}$, and ${\beta}=111.93(l)^{\circ}$. An X-ray crystal structure of complex 1 showed a short N(2)-N(3) distance ($1.265 {\AA}$) consistent with the valence tautomer A with Ir(III) rather than Ir(I). All complexes are highly colored and decompose on irradiation at 254 nm. Electrochemical studies show that complex 1 displays a quasi-reversible reduction.

• 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.