• Bulletin of the Korean Chemical Society
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• v.16 no.10
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• pp.981-984
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• 1995

New diamineplatinum(Ⅱ) complexes of cyclohexylidenemalonate (chm) ligand, A2Pt(OOC)2C=C(CH2)4CH2 (1, A2=ethylenediamine (en); 2, A2=propylenediamine (pn); 3, A=NH3; 4, A=isopropylamine (ipa)) have been prepared. Their oxidation with H2O2 has led to the corresponding dihydroxoplatinum(Ⅳ) complexes: cis, cis, trans-A2Pt((OOC)2C=C(CH2)4CH2)(OH)2 (5, A2=en; 6, A2=pn; 7, A=NH3; 8, A=ipa). The title complexes have been characterized by means of various spectroscopies and X-ray crystallography. 5 crystallizes in the monoclinic space group P21/a (Z=4) with a=12.098(7) Å, b=9.552(2) Å, c=16.258(4) Å, β=98.03(5)° and V=1860(1) Å3. The structure was refined to R=0.074. The local geometry around platinum atom is approximately octahedral with each hydroxide group in trans position. These platinum complexes are stable in aqueous solution. Pt(Ⅳ) complexes are readily reduced to the corresponding Pt(Ⅱ) complexes by ascorbic acid.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3835-3839
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• 2013

A new synthesis route for Pt nanoparticles by direct electrochemical reduction of a solid-state Pt ion precursor ($K_2PtCl_6$) is demonstrated. Solid $K_2PtCl_6$-supported polyethyleneimine (PEI) coatings on the surface of glassy carbon electrode were prepared by simple mixing of solid $K_2PtCl_6$ into a 1.0% PEI solution. The potential cycling or a constant potential in a PBS (pH 7.4) medium were applied to reduce the solid $K_2PtCl_6$ precursor. The reduction of Pt(IV) began at around -0.2 V and the reduction potential was ca. -0.4 V. A steady state current was achieved after 10 potential cycling scans, indicating that continuous formation of Pt nanoparticles by electrochemical reduction occurred for up to 10 cycles. After applying the reduction potential of -0.6 V for 300 s, Pt nanoparticles with diameters ranging from $0.02-0.5{\mu}m$ were observed, with an even distribution over the entire glassy carbon electrode surface. Characteristics of the Pt nanoparticles, including their performance in electrochemical reduction of $H_2O_2$ are examined. A distinct reduction peak observed at about -0.20 V was due to the electrocatalytic reduction of $H_2O_2$ by Pt nanoparticles. From the calibration plot, the linear range for $H_2O_2$ detection was 0.1-2.0 mM and the detection limit for $H_2O_2$ was found to be 0.05 mM.

• Resources Recycling
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• v.22 no.5
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• pp.29-34
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• 2013

Solvent extraction experiments were performed to separate platinum and rhodium from mixed chloride solution by using tri 2-ethylhexyl amine (TEHA) and its mixture with TBP and LIX 63. Effects of extraction conditions on the separation of the two metals were investigated as a function of extractant concentration in the HCl concentration range from 1 to 9 M. The concentration of Pt (IV) and Rh(III) was controlled to $1{\times}10^{-3}M$ and $2{\times}10^{-4}M$, respectively. In the extraction with TEHA and its mixture, Pt was quantitatively extracted irrespective of HCl concentration, while the extraction percentage of Rh depended on the extraction condition. When the concentration of HCl in the mixed solution was low, the extraction of Rh was nil and separation of Pt and Rh was possible. Adding TBP to TEHA had little effect on the extraction of both metals, while adding LIX63 to TEHA favored the extraction of Rh.

• Journal of the Korean institute of surface engineering
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• v.33 no.4
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• pp.261-265
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• 2000

Geometrically and chemically well defined Pt/alumina model catalysts have been prepared. To this end, we fabricated electrochemically alumina supports in which pores of constant size, length and shape were regularly distributed over a wide area of the surface. Platinum particles were dispersed on the pore surfaces via organometallic chemical vapor deposition technique using (trimethyl) methylcyclopentadienylplatinum (IV) as a precursor. The chemical composition of the alumina plane surfaces was examined by Auger electron spectroscopy and the adsorption characteristics of the platinum particles were studied by thermal desorption spectroscopy. A variety of industrial catalytic problems are now open for further investigation utilizing the Pt/alumina model catalysts.

• Journal of the Korean Chemical Society
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• v.56 no.1
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• pp.58-61
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• 2012

The solvent extraction of platinum (IV) metal from hydrochloric acid media using 4-(4-ethoxybenzylideneamino)-5-methyl-4H-1,2,4-triazole-3-thiol (EBIMTT) in chloroform was studied as a function of several variables, such as reagent, acid and metal ion concentration, effect of various diluents, and diverse ions. The proposed method was further applied for the separation of platinum (IV) from binary mixtures, synthetic mixtures, alloys and commercially available samples.

• Bulletin of the Korean Chemical Society
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• v.13 no.2
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• pp.158-162
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• 1992

Hydrocarbon solution of $(PPh_3)_2(CO)MOSO_2CF_3(M=Rh$, Ir)reacts rapidly with Pyrazine or 4,4'-bipyridyl to yield dinuclear metal complexes $[(PPh_3)_3(CO)M({\mu}-pyrazine)M(CO)(PPh_3)_2](SO_3CF_3)_2$ (I: M= RhH; III: M=Ir) or [$(PPh_3)_2$(CO)M(${\mu}$-44'-bipyridyl)M(CO)$(PPh_3)_2](SO_3CF_3)_2$, (II: M=Rh; IV: M=Ir), respectively. Compounds, I, II, III, and IV were characterized by $^1H-NMR$, $^{13}C-NMR$, $^{31}P-NMR$, and infrared spectrum. Ethanol solution of $(PPh_3)_2(CO)MOSO_2CF_3$ (M=Rh, Ir) also reacts with $(TBA)_2$M'$(CN)_4$ (M'=Pd, Pt) to yield trinuclear metal complexes [$(PPh_3)_2$(CO)dM-NCM'$(CN)_2$CN-M(CO)$(PPh_3)_2]$ (V : M=Rh, M'=Pd; VI : M=Rh, M'=Pt; VII: M=Ir, M'=Pd; VIII: M=Ir, M'=Pt). The trinuclear metal complexes V, VI, VII, and VIII are bridged by the cyanide groups. The infrared spectrum of V, VI, VII, and VIII supports the presence of the bridged cyanide and terminal cyanide group.

• Journal of Chest Surgery
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• v.22 no.3
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• pp.393-401
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• 1989

Between Dec. 1984, and May, 1988,96 prostheses were implanted in 80 patients at Dept. of Thoracic k Cardiovascular Surgery of National Medical Center. 43 patients had mitral valve replacement, 21 underwent aortic valve replacement, and 15 had double valve replacement [Mitral k Aortic], and 1 had tricuspid valve replacement. Seventy-one cases [88.8 %] were in NYHA Class III or IV. The mean duration of follow up was 22.1 months and follow-up information was available for 74 [92.5 %] of the patients. The overall actuarial survival rate at 45 months was 93.05 % and overall hospital mortality was 10 %, late Mortality was 5 %. The linearlized incidence of thromboembolism [2.4%/pt-yr], thrombotic valve obstruction [1.6 %/pt-yr], anticoagulant related bleeding [0.8 %/pt-yr]. There were no fatal valve related complications. The blood was studied in 40 patients 1 year after valve operation. Hgb and reticulocyte count were within normal values and Serum LDH value was slightly elevated but it was not of clinical significance. In conclusion, Monostrut Bjork-Shiley valve prosthesis to be a reliable valve substitute with an acceptable incidence of complications.

• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.19-24
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• 2001

A solvent sublation has been studied for the determination of trace Au(III), Pt(IV) and Pd(II) in waste water with their complexes of 2-mercaptobenzothiazole (MBT). Experimental conditions such as the concentration of HCl, the amount of MBT as a ligand, the type and amount of surfactants, bubbling rate and time, and the type of organic solvent were optimized for the solvent sublation, i.e., 25.0 mL of 2.0 M HCl solution and 30mL of 0.4%(w/v) MBT ethanolic solution were added to a 1.0 L sample to form stable complexes. The addition of 4.0 mL of 1 ${\times}$$10^{-3}$ M CTAB (cetyltrimehtylammonium bromide) solution was needed for the effective flotation accomplished by bubbling nitrogen gas at the rate of 40.0 mL/min for 35 minutes. As a solvent, 20.0 mL of MIBK (methylisobuthylketone) was used to extract the floated complexes. The procedure was applied to three kinds of waste waters. Au(III) was determined as 0.68 ng/mL and 0.98 ng/mL respectively for final washed water of two plating industries in Banwol. Pd(II) and Pt(IV) were not detected in any of the three samples. The recovery, which was obtained with analyte-spiked samples, were 95-120%.

• Journal of Chest Surgery
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• v.25 no.6
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• pp.661-671
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• 1992

From March 1988 to May 1991, 140 CarboMedics cardiac valve prostheses[75 mitral, 9 aortic and 28 double aortic-mitral] were implanted in 112 consecutive patients[mean age 36.7$\pm$11.6 years, male/female 48/76] by one surgical team operating on adult cardiac patients at Kyoungpook University Hospital Associated Surgical procedures were performed in 19 patients[16.9%]. Total follow up represented 2,345 patient-months[mean 22.4 months] and was 100% complete. Eighty-two patients[73%] were in NYHA functional class IIIor IV preoperatively and 102 patients [95%] were in class I or II postoperatively. Hospital[30 day] mortality was 4.4%, [3/75 mitral, 1/9 aortic, 1/28 double valve replacement] and late death was 1.7%. [1 /74 mitral, 1 /28 double valve replacement] The actuarial survival at 36 months was 94.0% after mitral, 80% after aortic, 92% after double valve replacement, and 93.2% for the total group. The linearized incidence of valve relater death, prosthetic valve thrombosis, anticoagulant related hemorrhage, and reoperation was 1.00%/pt-yr, 0.51%/pt/yr, 0.51%/pt-yr, and 0.51%/pt-yr respectively. The 36 month rates of freedom from valve replated death, thromboembolism, endocarditis, anti-coagulant related hemorrages, and reoperation were 98.75%, 99.08%, 100%, 99.04%, and 99.08% respectively. The 36 month rate of freedom from all valve related complications and deaths including hospital mortality was 90.2%. These fact suggest that the CarboMedics heart valve has excellent short-term result, low incidence of valve-related complications and valve dysfunction, and additional long term follow up study is necessary.

• Journal of Chest Surgery
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• v.24 no.1
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• pp.26-35
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• 1991

From January 1984 to June 1990, 188 patients have undergone cardiac valve replacement [114 MVR, 27 AVR, 47 Multiple valve replacement] with the St. Jude Medical prosthesis. The early mortality rate was 6.9%. The most common cause of early death was low output syndrome. There were no cases of valve-related early death. The risk factors for early death were advanced preoperative NYHA functional class [> IV], and prolonged ECC and ACC time. The 175 early survivors were followed-up for a total 372.7 patient-year over a period of 2 to 74 months [Mean $\pm$SD: 25.6$\pm$18.6 months]. During follow up, 12 patient died and late mortality rate was 6.9%. There were three valve-related late deaths: two were due to valve thrombosis and one was due to hemorrhage. Most late deaths [58%, 7/12] were from cardiac non-valvular causes. Valve-related complications occurred at a linearlized rate of 3.5% /pt-yr. Embolism occurred at a rate of 0.8% /pt-yr. There were three cases of valve thrombosis [0.8% /pt-yr: two fatal]. Hemorrhage due to anticoagulant occurred in 5 patients and a rate of 1.3% pt-yr [one fatal]. Five-year actuarial survival rate was 86.5 $\pm$5.1% and 97% of patient were in NYHA functional class I or II at three months postoperatively.