Study of small chlorine‐doped potassium clusters by thermal ionization mass spectrometry

The theoretical calculations have predicted that nonmetal‐doped potassium clusters can be used in the synthesis of a new class of charge‐transfer salts which can be considered as potential building blocks for the assembly of novel nanostructured material. In this work, K_nCl (n = 2–6) and K_nCl_n?1 (n = 3 and 4) clusters were produced by vaporization of a solid potassium chloride salt in a thermal ionization mass spectrometry. The ionization energies (IEs) were measured, and found to be 3.64 ± 0.20 eV for K₂Cl, 3.67 ± 0.20 eV for K₃Cl, 3.62 ± 0.20 eV for K₄Cl, 3.57 ± 0.20 eV for K₅Cl, 3.69 ± 0.20 eV for K₆Cl, 3.71 ± 0.20 eV for K₃Cl₂ and 3.72 ± 0.20 eV for K₄Cl₃. The K_nCl⁺ (n = 3–6) clusters were detected for the first time in a cluster beam generated by the thermal ionization source of modified design. Also, this work is the first to report experimentally obtained values of IEs for K_nCl⁺ (n = 3–6) and K_nCl_n?1⁺ (n = 3 and 4) clusters. The ionization energies for K_nCl⁺ and K_nCl_n?1⁺ clusters are much lower than the 4.34 eV of the potassium atom; hence, these clusters should be classified as ‘superalkali’ species. Copyright © 2012 John Wiley & Sons, Ltd.     

IR study of cation effects on the O-D stretching frequencies of isotopically dilute HDO in aqueous salt solutions

IR spectra of 3 normal solutions of 14 different salts [chlorides of Al⁺⁺⁺, Be⁺⁺, Mg⁺⁺, Ca⁺⁺, Sr⁺⁺, Ba⁺⁺, Zn⁺⁺, Cd⁺⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, N(CH₃) ₄ ⁺ ] in both, 96% H₂O+4% D₂O and 100% H₂O, were measured in the frequency range =2 800–2 100 cm^–1. From up to 18 single measurements for each solution the frequencies and halfwidths of the O-D stretching bands of isotopically dilute HDO were determined with high accuracy. Frequencies in the range =2 510–2 529 cm^–1 and halfwidths in the range =155–205 cm^–1 resulted atT=30°C with standard deviations typical less than ±1 cm^–1 and ±4 cm^–1, respectively. An almost perfect correlation between the O-D stretching band parameters and the polarizing power of the cations was obtained.Herrn Prof. Dr.A. Neckel, Wien, zum 60. Geburtstag gewidmet.     

Alkali metal ion-selective electrodes based on relevant alkali metal ion doped manganese oxides

Potentiometric properties of manganese oxides doped with alkali metal ions (Na⁺, K⁺, Rb⁺ and Cs⁺), which were prepared by heating mixed solutions (starting solution) of each alkali metal and Mn²⁺ ions, were examined. Electrodes based on mixed phases of Nao₄₄MnO₂/Mn₂O₃ and hollandite KMn₈O₁₆/M₂O₃ found by X-ray powder diffraction (XRD) exhibited Na⁺- and K⁺-selective responses with a near-Nernstian slope, respectively, when the molar ratio of alkali metal ion to Mn²⁺ ion in the starting solution was 0.1. When no alkali metal ions were added in the manganese oxide films, no significant potentiometric response was observed to any alkali metal ions. The selectivity coefficients of these electrodes were = 6.7 × 10^–2, = 7.1 × 10^–3, < 9 × 10^–4 and < 9x 10^–4 for the Na_0.44MnO₂/Mn₂O₃, and <4 × 10^–4 <4x 10^–4, =60 × 10^–2 ×10^–4, < 4 × 10^–4, for the KMn₈O₁₆/Mn₂O₃, respectively. Electrodes based on manganese oxides made from mixed solutions of Rb⁺/Mn²⁺ and Cs⁺/Mn²⁺ also responded to the respective primary ions, that is, Rb⁺ and Cs⁺ ions, although XRD patterns for the manganese oxides thus made did not show any peaks except for Mn₂O₃ (bixbyite); it was concluded in these cases that some amorphous type manganese oxides were formed in the Rb⁺/Mn²⁺ and Cs⁺/Mn²⁺ systems and they responded to the respective ions. Conditioning of these electrodes in an aerated indifferent electrolyte solution, 0.1M tetramethylammonium nitrate (TMA-NO₃), for relatively long time, typically more than 2 hours, was found to be a prerequisite for near-Nernstian response to the respective alkali metal ions. During this electrode conditioning, vacant sites (template) suitable in size for selective uptake of primary ions seemed to be formed by releasing the doped alkali metal ions from the solid phase into the adjacent electrolyte solution accompanying oxidation of the manganese oxide film.     

Untersuchungen an Kristallhydraten anorganischer Salze, 8. Mitt. Interpretation der Schwingungsspektren vonM(BF4)2·6H2O fürM=Fe2+, Co2+, Ni2+

The infrared and Raman spectra were recorded in the range 4000–160 cm^–1 forM(BF₄)₂·6 H₂O whereM=Fe²⁺, Co²⁺, Ni²⁺. The spectroscopic data support the X-ray structural data in showing that in the crystal hydrates studied two kinds of hydrogen bonds are present: H₂O...H₂O and OH₂... F₄B^–. The energies and molecular force constants (f _OH and fH₂O) andr _OH for OH₂...F₄B^– were calculated for the three crystal hydrates. It was found that the bond OH₂... F₄B^– is comparatively weak, with mean energy 3.7–3.3 kcal/mol. Two types of water molecule with different structures are existing as the first are participating in H₂O...H–O–H...F₄B^– and the second in BF₄ ^–...H–O–H...F₄B^–.     

Electronic structure,geometry, and stability of organic cations,dications, and donor-acceptor complexes

Geometric, electronic, and energy characteristics of the complexes formed in the CF₄ ·nAIF₃ (n = I or 2) and CBr₄ ·nAIBr₃ (n = 1, 2, or 4) systems have been determined by the semiempirical AM I method. Besides the donor-acceptor complexes, the CBr₃ ⁺...AIBr₄ ^–, CBr₃ ⁺...Al₂Br₇ ^–, CBr2²⁺...(AlBr₄ ^–)₂, and CBr₂ ²⁺...(Al₂Br₇ ^–)₂ ionic complexes can be formed in the CBr₄ ·nAlBr₃ systems. In the cations and dications of polyhalomethanes (when Hal = Cl, Br, or l) in both the free and bound (included in ionic complexes) states, carbon atoms carry negative charges, the C-Hal bonds are substantially shortened, and the positive charges are located on one-coordinate halogen atoms. These cations and dications can be considered as halenium ions that differ from halenium salts with dicoordinate halogen atoms. In the cationic and dicationic complexes of the CBr₄ ·nAlBr₃ systems, the maximum positive charges on the Br atoms are 0.39 and 0.94, respectively. Fluorine-containing cations and dications have structures similar to those of carbenium ions, whereas in the CF₄ ·nAIF₃ systems (n = l or 2), only donor-acceptor complexes are formed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 3, pp. 554–560, March, 1996.     

Field-evaporation mass spectroscopy applied to crown ether complexes with alkali and alkaline-earth metals

Field evaporation from solution has been used to detect crown-ether 15K5 and 18K6 coordination compounds formed with Na⁺, K⁺, Cs⁺, Ba²⁺ and Ca²⁺ in aqueous solution, both hydrated and unhydrated; the Ca²⁺·18K6·(H₂O)_n (n=0, 1, 2,...) compounds have been observed before. 18K6 present in the solution greatly increases the yields of 18K6 compounds with the dissociation products from Ba(NO₃)₂. The detection limits for 15K5 and 18K6 combined with Na⁺, K⁺, and Cs⁺ are approximately the same at 10^–7 g.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 2, pp. 239–242, March–April 1988.     

The interaction of alkali metal cations with aromatic molecules in complexes of the type M[AlMe3X]·aromatic,M[Al2Me6X]·aromatic,and related

The crystal structures of 13 compounds of the form M[Al₂Me₆X]·aromatic and related have been examined in order to learn about the M⁺...aromatic approach. Four types of interactions have been discerned: (1) metal...aromatic, (2) metal...aromatic...metal, (3) aromatic...metal...aromatic, and (4) no metal...aromatic contact. It was found that the closest K⁺...C(aromatic) and Cs⁺...C(aromatic) separations are essentially equal after a correction for the difference in metal radii. The strength of the K⁺...aromatic attraction was found to be sufficient to move the K⁺ ion 0.3 Å out of the plane of the crown ether in two complexes of dibenzo-18-crown-6.     

Stability of complex of Cs+ with valinomycin in nitrobenzene saturated with water

From extraction experiments and -activity measurements, the extraction constants corresponding to the equilibrium Cs⁺(aq)+Cl^–(aq)+L(nb)CsL⁺(nb)+Cl^–(nb) in the two-phase water-nitrobenzene system (L=valinomycin; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as log K_ex(CsL⁺, Cl^–)=2.2. Further, the stability constant of the valinomycin-cesium complex in nitrobenzene saturated with water was calculated: log _nb(Csl⁺)=10.1.     

The hydrolysis and fluoride complexation behavior of Fe(III) at 25°C and 0.68 molal ionic strength

Fe(III) hydrolysis and fluoride complexation behavior was examined in 0.68 molal sodium perchlorate at 25°C. Our assessment of the complexation of Fe(III) by fluoride ions produced the following results: log_F1 = 5.15₅, log_F2 = 9.10₇, log_F3 = 11.96, log_F4 = 13.7₅, where log_Fn = 5.15₅=[FeF _n ^(3-n)+ ][Fe³⁺]^–1[F^–]^–n. The stepwise fluoride complexation constants,FK _n+1, obtained in our work (where log_F K _n+1 =log_Fn) indicate that K _n+1/K _n =0.072±0.01. Formation constants for equilibria, Fe³⁺+nH₂OFe(OH) _n ^(3–n)+ +nH⁺, expressed in the form _n ^* [Fe(OH) _n ^(3-n)+ ][H⁺]ⁿ ,[Fe ³⁺]^-1, were estimated as ₁ ^* = –2.754, and ₂ ^* –7. Our study indicates that the results of previous hydrolysis investigations include very large overestimates of Fe(OH) ₂ ⁺ formation constants.     

Die Kristallstrukturen der Dicaesium-Dodekahalogeno-closo-Dodekaborate Cs2[B12X12] (X = Cl,Br, I) und ihrer Hydrate

The Crystal Structures of the Dicesium Dodecahalogeno-closo-Dodecaborates Cs₂[B₁₂X₁₂] (X = Cl, Br, I) and their Hydrates The perhalogenated derivatives Cs₂[B₁₂X₁₂] (X = Cl - I) have been synthesized by reaction of Cs₂[B₁₂H₁₂] with the respective elemental halogens (Cl₂, Br₂ and I₂). Upon recrystallization from aqueous solution colourless, face-rich single crystals of the dihydrates (Cs₂[B₁₂X₁₂] · 2 H₂O) are obtained first which can be dehydrated topotactically via the monohydrates (Cs₂[B₁₂X₁₂] · H₂O) leaving to the solvent-free compounds (Cs₂[B₁₂X₁₂]) behind without loss of their crystallinity. The ionic cesium salts were characterized by single crystal X-ray diffraction. All three halogenoborates are isostructural and they crystallize at room temperature in the trigonal space group (Cs₂[B₁₂Cl₁₂]: a = 959.67(3) pm, c = 4564.2(2) pm; Cs₂[B₁₂Br₁₂]: a = 997.92(3) pm, c = 4766.4(3) pm; Cs₂[B₁₂I₁₂]: a = 1047.05(4) pm, c = 5018.3(3) pm; Z = 6). The crystal structures consist of a cubic closest packed host lattice formed by two crystallographically inequivalent quasi-icosahedral [B₁₂X₁₂]^2- anions (Cs₂[B₁₂Cl₁₂]: d(B-B) = 178 - 179 pm, d(B-Cl) = 179 - 180 pm; Cs₂[B₁₂Br₁₂]: d(B-B) = 176 - 180 pm, d(B-Br) = 195 - 197 pm; Cs₂[B₁₂I₁₂]: d(B-B) = 177 - 182 pm, d(B-I) = 214 - 217 pm). By ordered occupation of half of the tetrahedral and formally all octahedral interstices in every intermediate layer with Cs⁺ cations, a structure emerges where (Cs1)⁺ is trigonally non-planar coordinated by three (CN = 9) and (Cs2)⁺ tetrahedrally coordinated by four (CN = 12) [B₁₂X₁₂]^2- anions. Thereby triangular faces of halogen atoms of the icosahedral clusters are coordinatively effective in both cases. In their mono- and dihydrates the incomplete coordination sphere of (Cs1)⁺ is completed by one and two water molecules, respectively. The thermal decomposition of the dicesium dodecahalogeno-closo-dodecaborate hydrates and their dehydration products was investigated using DTA/TG methods in a temperature range between room temperature and 1200 °C. Additionally the compounds were also characterized by ¹¹B-NMR spectroscopy in aqueous solution.     

Ion-exchange chromatography using vanadyl and vandate salts as mobile phases with indirect detection

Summary Vanadyl sulfate, VOSO₄, was characterized as the mobile phase for the ion exchange separation of Li⁺, Na⁺, NH ₄ ⁺ , and K⁺ using indirect photometric detection at 254 nm. Detection limits ranged from 0.2 ppm for Li⁺ to 1 ppm for K⁺. Indirect electrochemical detection of these separated cations by reduction of VO (II) to V³⁺ was compared to spectrophotometric detection. The potential of the vanadate species, HVO ₄ ^2– , for the separation of F^–, Cl^–, and SO ₄ ^2– , with indirect photometric detection was also demonstrated.     

Can Water Clusters Ionize HCl under the Conditions of Arctic Stratosphere? 1. Intermolecular Interactions

Pseudopotential model was constructed to simulate the H₃O⁺(H₂O) _n Cl^– clusters at room and stratosphere temperatures using the Monte Carlo method. Numerical values of interaction parameters were restored from the experimental data on the free energy and entropy of vapor nucleation on ions in the combination with the data of quantum chemical calculations of the optimal configurations of HCl(H₂O) _n clusters. The stability of various cluster structures and the probability of the rupture of intramolecular HCl bond in these clusters were analyzed.     

Sur le microdosage des ions fluorures par alcalimétrie indirecte

Résumé Les auteurs ont mis au point une méthode spécifique de microdosage titrimétrique des ions F^– susceptible d'être associée à une minéralisation préalable d'un échantillon de substance organique fluorée en vue d'y doser le fluor, à l'échelle microanalytique.Le principe en est fondé sur la réaction globale probable: 6 F^– + 4 H⁺ + SiO₂ +n K+ - SiF₆ ² + 2 H₂O +n K⁺, qui donne lieu à la disparition de 4 ions H+ du milieu réactionnel pour 6 ions F^– initialement présents. Cette consommation d'ions hydrogènes est mesurée par alcalimétrie et permet ainsi de doser le fluor. La réaction précédente ne se produit qu'en milieu acide, et en présence d'ions K⁺ sans précipitation apparente de fluosilicate de potassium.Le résultat brut du dosage doit subir une correction additive fonction de la teneur apparente correspondante en fluor et du volume de la solution et dont la valeur peut être déterminée à l'aide d'un diagramme établi expérimentalement.

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Summary A specific micro determination is given for the titrimetric determination of fluoride ions that is susceptible of being associated with a preliminary mineralization of a sample of a fluorine-bearing organic compound with a view of determining in it the fluorine on the micro scale. The fundamental principle is the probable total reaction: 6 F^– + 4 H⁺ + SiO₂ +n K⁺ SiF₆ ^6–2 + 2 H₂O +n K⁺ which leads to the disappearance of 4 H⁺ ions from the reaction milieu for each 6 F^– ions originally present. This consumption of ions is measured alkalimetrically and the fluorine content can be calculated accordingly. The above reaction occurs only in an acid medium and in the presence of K⁺ ions without apparent precipitation of potassium fluosilicate. The gross result of the determination must be corrected by an additive function of the apparent content corresponding to the fluorine present and to the volume of the solution. The value of this correction factor may be determined with the aid of a diagram which has been constructed on the basis of trials set up for this purpose.

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Zusammenfassung Eine neue spezifische Methode zur Mikrobestimmung von Fluoridionen wird angegeben. Diese eignet sich für organische fluorhältige Substanzen nach deren Mineralisierung. Sie beruht auf der wahrscheinlichen Reaktion: 6 F^– + 4 H⁺ + SiO₂ +n K⁺ * SiF₆ ^2– + 2 H₂O +n K⁺, wonach für je 6 Fluoridionen 4 Wasserstoffionen gebunden werden. Dieser Verbrauch an H-Ionen wird alkalimetrisch gemessen und bietet damit die Grundlage zur Fluorbestimmung. Diese erwähnte Reaktion findet nur in saurem Milieu bei Gegenwart von Kaliumionen statt, ohne daß es zu einer erkennbaren Ausscheidung von Kaliumsilicofluorid kommt. Dem Bruttoergebnis der Bestimmung ist eine Korrektur zuzuzählen, die von dem jeweiligen scheinbaren Fluorgehalt und dem Lösungsmittelvolumen abhängig ist und deren Größe sich aus einem experimentell ermittelten Diagramm ergibt.

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Travail publié en. l'honneur du 70ème anniversaire de Monsieur le professeur Dr.Hans Lieb.     

The Cl−NH3, Cl−H2O,F−NH3 and F−H2O clusters and their photoelectron spectra

The geometries of the Cl^–NH₃, Cl^–H₂O, F^–NH₃ and F^–H₂O clusters are optimized using the coupled cluster method. The four lowest ionization potentials are then calculated, leading to the ground and low excited states of the neutral species. The first three IPs describe ionization from the externalp state of the halogen atom, whereas the fourth corresponds to ionization from the NH₃ or H₂O moiety, leading to charge transfer complexes. These complexes were recently observed in the photoelectron spectrum of Cl^–NH₃, in full accord with our calculations.Supported in part by the U.S.-Israel Binational Science Foundation     

Production of hyperlithiated Li2F by a laser ablation of LiF–Li3N mixture

Lithium-excess binary clusters Li_nF_n−1 (n=2–9) were detected by photoionization time-of-flight mass spectrometry in a supersonic cluster beam generated by a laser ablation of a solid mixture of lithium fluoride and nitride. Laser power dependence of the Li₂F⁺ signal intensity has indicated that the ionization energy of the hyperlithiated Li₂F molecule is lower than 4.66 eV. The theoretical vertical ionization energy obtained by the CCSD(T)/6-311+G(d)//B3LYP/6-311+G(d) calculations are 4.47 eV. No nitrogen-containing clusters were detected. The absence of Li₄N is ascribed to the exothermicity of the reaction, 2Li₃N→N₂+Li₆.     

Caesiumchromhalogenide Cs3CrCl6, Cs3Cr2Cl9 und Cs3CrBr6 – Darstellung,Eigenschaften, Kristallstruktur

Cesium Chromium Halides Cs₃CrCl₆, Cs₃Cr₂Cl₉, and Cs₃CrBr₆ – Preparation, Properties, Crystal Structure The crystal structures of Cs₃CrCl₆ and Cs₃Cr₂Cl₉ were determined and redetermined by X‐ray single‐crystal studies (space group Pnnm, Z = 6, a = 1115.6(2) pm, b = 2291.3(5) pm, c = 743.8(1) pm, R_f = 7.73%, 1025 unique reflections with I > 2σ(I) (Cs₃CrCl₆); P6₃/mmc, Z = 2, a = 721.7(2) pm und c = 1791.0(1) pm; R_f = 2.06%, 395 unique reflections with I > 2.5σ(I) (Cs₃Cr₂Cl₉). The structure of Cs₃CrCl₆ consists of two different isolated CrCl₆ octahedra and five crystallographic different Cs⁺ ions. The CrCl₆ octahedra form ropes in the direction [001]. Because of orientational disordering of the Cr(1)Cl₆ octahedra and the an only half‐occupation of some cesium and chlorine sites Cs₃CrCl₆ is strongly disordered in direction of the (020) plane. The ionic conductivity of Cs₃CrCl₆, which was expected owing to the great disorder, however, is with 7.3 × 10^–5 Ω^–1 cm^–1 at 740 K relatively small. The compound Cs₃CrBr₆, which was firstly prepared by quenching stoichiometric amounts of CsBr and CrBr₃ from 833 K, is metastable at ambient temperature. It is probably isostructural to Cs₃CrCl₆ as shown by X‐ray powder photographs.     

Ag Clusters as Active Species for HC-SCR Over Ag-Zeolites

The addition of hydrogen in the reaction atmosphere is effective in promoting the activity of Ag/alumina and Ag-zeolites on the selective reduction of NO by hydrocarbons (HC-SCR) at low temperatures. The increment of NO conversion over Ag-MFI corresponds to the periodic addition of hydrogen into C₃H₈-SCR conditions. The UV–VIS spectra of Ag-MFI have revealed that the addition of hydrogen results in the formation of Ag_n^δ+ clusters due to partial reduction and agglomeration of Ag species. The coincidence of the formation of the Ag_n^δ+ clusters and the increment of NO conversion suggests that Ag_n^δ+ clusters are the highly active species for HC-SCR. From analysis by H₂-TPR, UV–VIS, and EXAFS, the structure of Ag_n^δ+ clusters on Ag-MFI is identified as being Ag₄²⁺ on average. The formation of Ag clusters was strongly affected by the type of zeolites: The major Ag species are Ag⁺ ions for MOR, Ag_n^δ+ clusters for MFI and BEA, and relatively large metallic Ag_mparticles for Y. The sequence of Ag agglomeration (MOR < MFI < BEA < Y) is in accordance with the strength of the acid sites of zeolites. It can be expected that the interaction between the positive charge of Ag_n^δ+ clusters and acid sites, i.e., the ion-exchange site of zeolites, stabilizes Ag_n^δ+ clusters. The type of Ag species under HC-SCR conditions depends on the concentration of gas-phase oxidants (NO, O₂) and reductants (H₂, HC), and also on the number and strength of the zeolite acid sites.     

Distribution studies of metal ions on arsenophosphates of Sn(IV) and Cr(III) and on amine Sn(II) hexacyanoferrates (II) using radio tracers: Separation of Sr2+−Cs+, Hg2+−Ag+ and Hg2+−Zn2+

Summary Distribution studies of some metal ions have been made on Sn(IV) and Cr(III) arsenophosphates and on some samples of Sn(II) amine hexacyanoferrates(II), using radiotracers. The K_d values of Cs⁺ and Rb⁺ have been followed at varying HNO₃ concentrations also. As a result 3 useful binary separations have been achieved on Sn(IV) and Cr(III) arsenophosphates, such as Sr²⁺–Cs⁺, Hg²⁺–Ag⁺ and Hg²⁺–Zn²⁺.     

Influence of Anions on Electrochemical Properties of Polypyrrole-Modified Electrodes

The influence of anions ClO₄ ^–, NO₃ ^–, Cl^–, SO₄ ^2–, and DDS^– (dodecyl sulfate) on the cyclic voltammetric response of polypyrrole-modified electrodes is studied. The change in the film composition is examined by electron probe microanalysis. It is established that essential changes in the shape of voltammograms take place during cycling if the anions are not sufficiently freely mobile in the polymer film and insertion of cations from the solution is necessary to guarantee electroneutrality of the system. Some differences between the mobility of Cl^– ions and ClO₄ ^– or NO₃ ^– ions are in good agreement with the results of semi-empirical quantum chemical calculations showing that the interaction of Cl^– and Br^– ions with pyrrole oligomers is stronger than that of NO₃ ^– or ClO₄ ^– ions. Nevertheless, it is established that the peak current determined from voltammograms increases linearly with the increase of the scan rate with very high correlation coefficient. It means that it is possible to describe the behavior of ClO₄ ^–, NO₃ ^– and Cl^– ions in the framework of the model of free ions. The redox behavior of the PPy films doped with anions of low mobility such as SO₄ ^2– and DDS^– depends essentially on the nature of cations in the test solution. It is found that the mobility of cations increases in the row Li⁺ < Na⁺ < K⁺ < Cs⁺. The mobility of DDS^– ions in the PPy in ethanolic solution is significantly higher and their electrochemical properties are quite similar to PPy|Cl or NO₃ ^– film in aqueous solution.     

Cesium dimethyltetrachloroplatinate,a complex of dimethylplatinum(IV). Synthesis and some reductive elimination reactions involving the monomethylplatinum(II) complex as an intermediate

The reduction of Pt(IV) complexes followed by the oxidative addition of dimethyl sulfate to Pt(II) affords Cs₂PtMe₂Cl₄, a complex of dimethylplatinum(IV). On treatment with such nucleophiles as Cl^–, Br^–, I^–, and PtCl₄ ^2– in aqueous solutions at 368 K this complex undergoes reductive elimination to give MeX and Pt^IIMe as a transient species. The latter is further converted to methane upon protolysis, whereas in the presence of an oxidant (Na₂PtCl₆) it gives rise to the Pt^IVMe species. The kinetics of decomposition of Cs₂PtMe₂Cl₄ in aqueous HCl-KCl systems (2M or 3M in Cl^–; [Pt^IVMe₂][Cl^–]) were studied. The reaction takes place as anS _N 2 attack of X^– on the carbon atom of a methyl group located with thetrans position with respect to the aqua-ligand of the [PtMe₂Cl₃(H₂O)]^– complex.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 389–395, February, 1993.