• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1283-1288
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• 2010

A novel polyaminopolycarboxylate ligand with many coordination sites, N,N,$N^1,N^1,N^2,N^2$-[( 2,4,6-tri(aminomethyl)-pyridine]hexakis(acetic acid) (TPHA), was designed and synthesized and its lanthanide complexes $Na_6Tb_2$(TPHA)$Cl_6{\cdot}14H_2O$, $Na_6Eu_2$(TPHA)$Cl_6{\cdot}8H_2O$, $Na_6Gd_2$(TPHA)$Cl_6{\cdot}11H_2O$ and $Na_6Sm_2$(TPHA)$Cl_6{\cdot}9H_2O$ were successfully prepared. The ligand and the complexes were characterized by elemental analysis, IR, mass, NMR and TG-DTA. The TG-DTA studies indicated that the complexes had a high thermal stability, whose initial decomposition temperature was over $270^{\circ}C$. The luminescence properties of the complexes in solid state were investigated and the results suggested that $Tb^{3+}$ and $Eu^{3+}$ ions could be sensitized efficiently by the ligand, especially the Tb(III) complex displayed a very strong luminescence intensity (> 10000) and only displayed characteristic metal-centered luminescence. Also, the correlative comparison between the structure of ligand and luminescence properties showed how the number of the coordination atoms of ligand can be a prominent factor in the effectiveness of ligand-to-metal energy transfer.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.569-577
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• 2003

Ligands, Br-PEMP, Cl-PEMP and $CH_3O-PEMP$ having Br, Cl and $CH_3O$ substituents at 5-position of the $N_2O$ tridentate ligand, 2-[(2-pyridine-2-ethylamio)-methyl]-phenol (H-PEMP) containing pyridine and phenol were synthesized. Another ligand, Naph-PEMP having pyridine and 2-hydroxy-1-naphthalene was also synthesized. The ligands were characterized using elemental analysis, UV-visible, IR, $^1H\;NMR\;and\;^{13}C$ NMR spectroscopy and mass analysis. The potentiometric titration study in aqueous solution revealed that the proton dissociation of the ligands occurred in three steps and the order of overall proton dissociation constants (log${\beta}$) was $CH_3O-PEMP$ > Naph-PEMP > H-PEMP > Cl-PEMP > Br-PEMP. The order of stability constants (logML and log$ML_2$) of their transition metal complexes was Co(II) < Ni(II) < Cu(II) > Zn(II). The order in their stability constants values of each transition metal complex agreed well with that in overall proton dissociation constant value of the ligands.

• Archives of Pharmacal Research
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• v.17 no.6
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• pp.411-414
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• 1994

Phenylazocyanothioacetamide 1 reacts with malononitrile to afford the pyridinethione 4 which reacts with phenacylbromide to yield the pyridine-S-phenacyl derivative 6, 1 reacts with ethyl cyanoacetate to yield the pyridazine derivative, 8, and with phenacyl bromide to afford the N-phenacyl derivative 11, instead of the thiazole 10. Compound 11 afforded the pyrazolopyridine 13 on reaction with malononitrile while 10 was obtained on coupling of the thiazole 14 with diazotised aniline. Compound 10 reacts with malononitrile to afford the thizaolyl pyridazine 15. Compound 1 reacts with malononitrile dimer to afford the pyriodopyridazine derivative 17a. 1 reacts also with active methylene heterocycies to afford the pyrazolo and thiazolo-fused phridazines 20 and 23 respectively.

• Macromolecular Research
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• v.13 no.1
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• pp.2-7
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• 2005

A series of ethylene polymerization catalysts based on tridentate bis-imine ligands coordinated to iron and cobalt was reported. The ligands were prepared through the condensation of sterically bulky anilines with allyloxy-and benzyloxy-substituted 2,6-acetylpyridines. The pre-catalyst complexes were penta-coordinate species of the general formula $\{[(ArN=C(Me))_2(4-RO-C_5H_3N)]MCl_2\}$ (Ar=ortho dialkyl-substituted aryl ring; R=allyl, benzyl; M=Fe, Co). In the presence of ethylene and methyl alumoxane cocatalysts, these complexes were active for the polymerization of ethylene, with activities lower than those of metal complexes of the general formula $\{[(2-ArN=C(Me)_2C_5H_3N]MCl_2\}$ (Ar=ortho dialkyl-substituted aryl ring; M=Co, Fe), containing no substituents in 2,6-acetylpyridine ring. The effects of the catalyst structure and temperature on the polymerization activity, thermal properties, and molecular weight were discussed.

• Macromolecular Research
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• v.17 no.10
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• pp.739-745
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• 2009

N,N'-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids 3a-g were synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride 1 with two equimolars of Lalanine 2a, L-valine 2b, L-leucine 2c, L-isoleucine 2d, L-phenyl alanine 2e, L-2-aminobutyric acid 2f and L-histidine 2g in an acetic acid solution. Seven new poly(amide-imide)s PAIs 5a-g were synthesized through the direct polycondensation reaction of seven chiral N,N'-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids 3a-g with bis(3-amino phenyl) phenyl phosphine oxide 4 by two different methods: direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride ($CaCl_2$/pyridine (py), and direct polycondensation in a tosyl chloride (TsCl)/pyridine (py)/N,N-dimethylformamide (DMF) system. The polymerization reaction produced a series of flame-retardant and thermally stable poly(amide-imide)s 5a-g with high yield. The resulted polymers were fully characterized by FTIR, $^1H$ NMR spectroscopy, elemental analyses, inherent viscosity, specific rotation and solubility tests. Data obtained by thermal analysis (TGA and DTG) revealed that the good thermal stability of these polymers. These polymers can be potentially utilized in flame retardant thermoplastic materials.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1709-1714
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• 2002

4-Aryl-3-cyano-6-(2'-thienyl)-pyridine-2(1H)-thiones(1a-c) were reacted with phenacyl bromide, chloro-N-arylacetanmides or 2-chloroacetylaminopyridine to furnish 2-functionalized 3-amino-4-aryl-6-(2'-thienyl)-thieno[2,3-b]pyridines 4a-c and 5a-c or 5d respecitively. The compounds 5a-d underwent different sequence of reactions to produce a variety of thienylpyridothienopyrimidines and, thienylpyridothienotriazines. Some of the prepared compounds were tested in vitro for their antimicrobial activities.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1797-1802
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• 2007

The kinetics and mechanism of the nucleophilic substitution reactions of diphenyl phosphinic (1) and thiophosphinic (2) chlorides with substituted X-pyridines are investigated kinetically in acetonitrile at 35.0 and 55.0 oC, respectively. A concerted mechanism with backside nucleophilic attack is proposed for the pyridinolysis of 1, on the basis of the linear Bronsted plot with the βX value of 0.68. In the case of the pyridinolysis of 2, the Hammett and Bronsted plots are biphasic concave upwards with the break point at 3- phenyl pyridine. These results indicate a change in mechanism from a concerted SN2(P) process with direct backside nucleophilic attack for less basic nucleophiles (X = 3-CN-3-Ph) to a stepwise process with frontside attack for more basic nucleophiles (X = 4-MeO-3-Ph). Apparent secondary inverse kinetic isotope effects with deuterated pyridine (C5D5N), kH/kD < 1, are observed for the pyridinolysis of 1 and 2.

• Journal of the Korean Vacuum Society
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• v.12 no.4
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• pp.263-268
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• 2003

Precise thickness control and excellent properties of silicon nitride thin films are essential for the next-generation semiconductor and display devices. In this study, silicon nitride thin films were deposited by batch-type atomic layer deposition (ALD) method using $SiC1_4$ and $NH_3$ as the precursors at temperatures ranging from 500 to $600^{\circ}C$. Thin film deposition using a batch-type ALD reactor was a layer-by-layer atomic growth by self-limiting surface reactions, and the thickness of the deposited film can be controlled by the number of deposition cycles. The silicon nitride thin films deposited by ALD method exhibited composition, refractive index and wet etch rate similar with those of the thin films deposited by low-pressure chemical vapor deposition method at $760^{\circ}C$. The addition of pyridine mixed with precursors increased deposition rate by 50%, however, the films deposited with pyridine was readily oxidized owing to its unstable structure, which is unsuitable for the application to semiconductor or display devices.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.553-557
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• 2004

Aroma compounds in Pholiota adiposa were extracted by simultaneous distillation and extraction (SDE), and 41 compounds were identified by GC-MS, including eleven alcohols, eight aldehydes, four esters, four ketones, nine alkans, and five miscellaneous compounds. Major aroma compounds included hexanal (8.55%), n-heptaldehyde (13.02%), 2-pentyl furan (4.82%), benzeneacetaldehyde (3.34%), (E,Z)-2,4-decadienal (3.06%), and hexacosane(5.04%). Drying method was applied to aroma compounds of Pholiota adiposa extracted by solid phase microextraction and identified by GC-MS. As hot air-drying temperature increased, peak areas (%) of 2-phenylethanol and benzeneacetaldehyde decreased, whereas those of 2(5H)-furanone (0.16%), 2H-1-benzopyran-2-one (7.63%), 2-acetylpyrrole (5.49%), and 4-phenyl-pyridine (5.61%) increased significantly at $70^{\circ}C$.

• Archives of Pharmacal Research
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• v.28 no.8
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• pp.983-987
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• 2005

Hydrogels composed of glycidyl methacrylate dextran (GMD) and poly(acrylic acid, PM) were prepared by UV irradiation method for colon-specific drug delivery. GMD was synthesized by coupling of glycidyl methacrylate to dextran in the presence of 4-(N,N-dimethylamino)pyridine. GMD was photo-polymerized by ammonium peroxydisulfate as initiating system in phosphate­buffered solution (0.1 M, pH 7.4). And then, acrylic acid monomer was added and subsequently heat-polymerized by 2,2'-azobisisobutyronitrile as an initiator. The hydrogels exhibited high swelling ratio (about 20) at $37^{\circ}C$, and showed a pH-dependent swelling behavior. In addition, the swelling ratio of the hydrogel was remarkably enhanced to about 45 times in the presence of dextranase at pH 7.4. The swelling-deswelling behavior proceeded reversibly for the GMD/PM hydrogels between pH 2 and pH 7.4. Release of 5-aminosalicylic acid from the GMD/PAA hydrogels was evaluated in simulated gastrointestinal pH fluids in the absence or presence of dextranase. We concluded that the hydrogels prepared could be used as a dual-sensitive drug carrier for sequential release in gastrointestinal tract.