• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1405-1417
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• 2006

The geometrical structures, potential energy surfaces, and energetics for the ligand exchange reactions of tetracoordinated platinum $(PtY_2L_2\;:\;Y,\;L=Cl^-,\;OH^-,\;OH_2,\;NH_3)$ complexes in the ligand-solvent interaction systems were investigated using the ab initio Hartree-Fock (HF) and Density Functional Theory (DFT) methods. The potential energy surfaces for the ligand exchange reactions used for the conversions of $(PtCl_4\;+\;H_2O)^{^\ast_\ast}\;to\;[PtCl_3(H_2O)\;+\;Cl^-]$ and $[Pt(NH_3)_2Cl_2\;+\;H_2O]$$[Pt(NH_3)_2Cl_2\;+\;H_2O]$ to $[Pt(NH_3)_2Cl(H_2O)\;+\;Cl^-] $ were investigated in detail. For these two exchange reactions, the transition states $([PtY_2L_2{\cdot}{\cdot}{\cdot}L^\prime])^{^\ast_\ast} $ correspond to complexes such as $(PtCl_4{\cdot}{\cdot}{\cdot}H_2O)^{^\ast_\ast}$ and $[Pt(NH_3)_2Cl_2{\cdot}{\cdot}{\cdot}H_2O]^{^\ast_\ast}$, respectively. In the transition state, $([PtCl_4{\cdot}{\cdot}{\cdot}H_2O]^{^\ast_\ast}$ and $[Pt(NH_3)_2Cl_2{\cdot}{\cdot}{\cdot}H_2O]]^{^\ast_\ast})$ have a kind of 6-membered $(Pt-Cl{\cdot}{\cdot}{\cdot}HOH{\cdot}{\cdot}{\cdot}Cl)$ and $(Pt-OH{\cdot}{\cdot}{\cdot}Cl{\cdot}{\cdot}{\cdot}HN)$ interactions, respectively, wherein a central Pt(II) metal directly combines with a leaving $Cl^-$ and an entering $H_2O$. Simultaneously, the entering $H_2O$ interacts with a leaving $Cl^-$. No vertical one metal-ligand interactions $([PtY_2L_2{\cdot}{\cdot}{\cdot}L^\prime]) $ are found at the axial positions of the square planar $(PtY_2L_2)$ complexes, which were formed via a vertically associative mechanism leading to $D_{3h}$ or $C_{2v}$-transition state symmetry. The geometrical structure variations, molecular orbital variations (HOMO and LUMO), and relative stabilities for the ligand exchange processes are also examined quantitatively. Schematic diagrams for the dissociation reactions of {PtCl4(H2O)n(n=2,4)} into {$PtCl_3(H_2O)_{(n-2)}\;+\;Cl^-(H_2O)_2$} and the binding energies {$PtCl_4(H_2O)_n$(n = 1-5)} of $PtCl_4$ with water molecules are drawn.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.339-345
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• 2007

Urea reacts with PtCl2, H2[PtCl6]·6H2O, H2[IrCl6] and Ni(CH3CO2)2 in aqueous solution at high temperature (60-80 °C) yielding [PtCl2(Urea)]·2H2O (1), (NH4)2[PtCl6] (2), (NH4)2[IrCl6]·H2O (3) and [Ni2(OH)2(NCO)2(H2O)2] (4) complexes, respectively. In complex 1, urea coordinates to Pt(II) as a neutral bidentate ligand via amido nitrogen atoms. In complexes 2, 3 and 4 it seems that the coordinated urea molecules decompose during the reaction at high temperature and a variety of reaction products are obtained. All complexes were isolated in moderate yields as dark green (1), yellow (2), pale brown (3) and faint green (4) precipitates, respectively. The reaction products were characterized by their microanalysis, IR, 1H and 13C NMR spectra as well as thermal analysis. General mechanisms describing the formation of these complexes were suggested.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.435-436
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• 2008

Dye-sensitized Solar Cells(DSSCs) which convert incident sun light into electricity were expected to overcome global warming and depletion of fossil fuels. And it is one of study that is lately getting into the spotlight because manufacturing method is more simple and inexpensive than existing silicon solar cells. In this respect, DSSCs are in the limelight as the next generation solar cells. DSSCs are generally composed of a dye-modified $TiO_2$ photoelectrode, a Pt counter electrode, and an electrolytes containing a redox couple$(I^-/I_3^-)$. Among these elements, pt electrode were prepared by applying electric potential to FTO substrate in the $H_2PtCl_6$ solution. In this study, we report the solar cell efficiency depending on $PtCl_4$ concentration change. $PtCl_4$ concentration was 1mM, 5mM, 10mM, and 20mM, and adhered on FTO glass substrate by sintering process. When applied each $PtCl_4$ counter electrode on DSSC, the best efficiency was found at 10mM of $PtCl_4$ concentration. The catalyst promotes the movement of electron from the counter electrode to the electrolyte the higher the molarity, the better the efficiency. However, in case of 20mM, it is estimated that over-deposited $PtCl_4$ tends to restrict the movement of electron due to its bundle formation.

• Resources Recycling
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• v.18 no.1
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• pp.30-37
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• 2009

Distribution diagram of Pt(IV), Pd(II), and Rh(III) in HCl solution was obtained as a function of HCl concentration from 0.001 to 10 M by considering complex formation reaction together with mass balance. When HCl concentration was higher than 0.1 M, most of Pt and Pd in HCl solution exist as $PtCl_6^{2-}$ and $PtCl_4^{2-}$. The concentration of HCl had a feat effect on the speciation of Rh(III). As HCl concentration increases from 0.1 to 10 M, the pedominant species changes from $PhCl_5^{2-}$ to $PhCl_6^{3-}$. Interaction parameters of $PtCl_6^{2-}$ and $PdCl_4^{2-}$ with hydrogen ion were evaluated from the solvent extraction data of Pt and Pd reported in the literature.

• Journal of the Korean Chemical Society
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• v.37 no.8
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• pp.717-722
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• 1993

Reactions of [PtCl$_4$]$^{2-}$ with excess of dithiocarbamates in water lead to facile replacement of the chloro ligand by dithiocarbamato ligand to give [Pt(A)], [Pt(B)$_2$]Cl$_2$, [Pt(C)$_2$], and [Pt(D)(CH$_2$=CH$_2$)Cl]Cl. The complexes of platinum have been characterized by elemental analyses, infrared and UV-visible spectra, and conductivity measurements. Platinum(II)-dithiocarbamate complexes were soluble in polar solvents such as water, alcohol, acetone, dimethylformamide, and dimethylsulfoxide etc. The possible structure was proposed on the basis of elemental analyses and physical properties.

• Bulletin of the Korean Chemical Society
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• v.10 no.5
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• pp.443-447
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• 1989

The mechanism on the oxidative addition reaction of $(TBA)_2\;Pt(CN)_4$ with $Cl_2$ has been studied by means of extended Huckel calculations. Among two possible mechanisms, computational calculations demonstrated that the linear approach of $Cl_2$ to a $Pt(CN)_4$ moiety is more favourable than three-centered transition state. From our calculations, the most stable process is that a $Pt(CN)_4$ moiety interacts with $Cl_2$ in the linear transition state and the cleavage of Cl-Cl bond in a coordinated halogen occurred spontaneously, giving rise to a trans product by back-attacking a $Pt(CN)_4Cl$ moiety by Cl. The process consists of the comparison in the stability of each intermediate with use of bonding and potential energy.

• Bulletin of the Korean Chemical Society
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• v.17 no.11
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• pp.1061-1065
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• 1996

The charge transfer compounds of tetrathiafulvalene (TTF) with the general formula of (TTF)mMCln, (M=Au, Pt, Ir, Os) were prepared by the direct reaction using excess HAuCl4·3H2O, H2PtCl6·xH2O, H2IrCl6·xH2O and H2OsCl6 respectively. The powdered electrical conductivities (σrt) at room temperature are given as follows; (TTF)3AuCl2, 4.53×10-3; (TTF)3.5AuCl2, 6.37×10-3; (TTF)3PtCl4, 5.51×10-4; (TTF)2IrCl4, 2.40×10-5; (TTF)OsCl4·1/2C2H5OH, 4.46×10-7 Scm-1. Magnetic susceptibility, electronic (UV-Vis.), vibrational (IR) and EPR spectroscopic evidences indicate that there is incomplete charge transfer from the TTF donor to gold, platinum, and iridium respectively, and that there is essentially complete charge transfer to osmium, thereby resulting a relatively low electrical conductivity in osmium compound. The EPR and magnetic susceptibility data reflect that the metals are in diamagnetic Au(Ⅰ), Pt(Ⅱ), Ir(Ⅲ), and Os(Ⅱ) oxidation states, and the odd electrons are extensively delocalized over the TTF lattices in each compound.

• Bulletin of the Korean Chemical Society
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• v.6 no.4
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• pp.214-217
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• 1985

Platinum(II) complexes of R-2,2'-diaminobinaphthyl (R-dabn), [Pt(R-dabn)(H2O)2]Cl2, [Pt(R-dabn)(R-Pn)]Cl2, [Pt(R-dabn)(R-bn)]Cl2, and platinum(II) complexes of S-2,2'-diaminobinaphthyl (S-dabn), [Pt(S-dabn)(H2O)2]Cl2, [Pt(S-dabn)(S-Pn)]Cl2, and [(Pt(S-dabn)(S-bn)]Cl2 have been prepared. (R-Pn and S-Pn are, respectively R- and S isomer of 2,3-diaminobutane). R-Pn and S-bn are, respectively R and S isomer of 2,3-diaminopropane). In the vicinity of the B-absorption band region of dabn, the circular dichroism spectra of platinum(Ⅱ) complexes of R-dabn series show a positive B-band followed by a negative higher energy A-band, which is generally understood as the splitting pattern for a ${\lambda}$ conformation, while the circular dichroism spectra of platinum(Ⅱ) complexes of S-dabn series show a negative B-band followed by a positive higher energy A-band in the long-axis polarized absorption region as expected for a $\delta$ conformation.

• Resources Recycling
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• v.16 no.5
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• pp.36-40
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• 2007

Platinum plays an important role in many applications because of its extraordinary physical and chemical properties. All these applications require the use of platinum in the finely divided state. Therefore the preparation of platinum nanoparticles by reducing platinum-surfactant salt with reducing agent in the solution was investigated in this study. The net interaction between C14TABr and $H_2[PtCl_6]$ in aqueous solution results in the formation of $[C14TA]_2[PtCl_6]$. The concentration of C14TABr and the concentration of $H_2[PtCl_6]$ has to be above cmc and 0.32 mM, respectively in order to obtain complex-micelle aggregation for mono dispersed Pt particles. Pt particle size increases with increasing $H_2[PtCl_6]$ and C14TABr concentration. And the shape of Pt particles was well controlled with increasing surfactant concentration.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.804-808
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• 1998

The inductively coupled plasma(ICP) etching of platinum with BCl$_3$/Cl$_2$ gas chemistry has been studied. X-ray photoelectron spectroscopy (XPS) was used to investigate the chemical binding states of the etched surface. The plasma characteristics was extracted from optical emission spectroscopy (OES) and a single Langmuir probe. In this case of Pt etching using BCl$_3$/Cl$_2$ gas chemistries, the result of OES and Langmuir probe showed the increase of Cl radicals and ion current densities in the plasmas with increasing Cl$_2$ gas ratio. At the same time, XPS results indicated that the intensities of Pt 4f decreased with increasing Cl$_2$ gas ratio. The decrease of Pt 4f intensities implies the increase of residue layer thickness on the etched Pt surface.