Chemical transformations of a SiO2-supported [Fe5RhC(CO)16]− cluster and catalysis of propylene hydroformylation

Chemical transformations of SiO₂-supported [Fe₅RhC(CO)₁₆]^– and [Fe₄RhC(CO)₁₄]^– clusters in Ar, CO, and synthesis gas are studied by IR spectroscopy, Mössbauer spectroscopy, and transmission electron microscopy. It is shown that partial transformation of the [Fe₅RhC(CO)₁₆]^– cluster to the [Fe₄RhC(CO)₁₄]^– cluster occurs immediately after its deposition on the substrate surface with the simultaneous formation of Fe²⁺ ions. The complete conversion of the supported [Fe₅RhC(CO)₁₆]^– cluster to [Fe₄RhC(CO)₁₄]^– is observed at 323 K in the synthesis gas. At 373 to 423 K [Fe₅RhC(CO)₁₆]^– transforms into a mixture of Fe₄Rh₂C(CO)₁₆, [Fe₄RhC(CO)₁₄]^–, and [Fe₅₃Rh₃C(CO)₁₅]^– clusters. In the 523 to 623 K range, the supported [Fe₅RhC(CO)₁₆]^– cluster decarbonylates completely to form bimetallic species Å 5 Å in size. Silica-supported FeRh clusters are active in propylene hydroformylation at 423 to 473 K and form a mixture of butyl alcohols and butyraldehydes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 632–641, April, 1995.This work was financially supported by the Krasnoyarsk Region Scince Foundation (Grant No. 1F0020).     

Theoretical calculations of95Mo-NMR chemical shifts for compounds [MoO4−n S n ]2−

Summary Theoretical calculation of⁹⁵Mo-NMR chemical shifts for [MoO_4–n S _n ]^2– (n=0–4) compounds is reported here for the first time on the basis of Fenske-Hall method and Sum-Over-State (SOS) perturbation theory. A systematic decrease in shielding of⁹⁵Mo nuclei with increase of number of sulfur in [MoO_4–n S _n ]^2–, which is observed experimentally, can be reasonably explained by our calculation. A good linear relationship between chemical shifts of calculation and experiment is obtained. The electronic structure and bonding in these compounds are also discussed.Supported by Nature Science Foundation of China     

Synthesis,stability and reactivity of cationic carbonyl complexes of rhodium(I)

Summary Trans-[RhCl(CO)L₂] (L = PPh₃, AsPh₃ or PCy₃) react with AgBF₄ in CH₂Cl₂ to give the novel species [Rh-(CO)L₂]⁺ [BF₄]^–.nCH₂Cl₂ (n = 1/2 or 1 1/2) (1–3), which we believe to be stabilised by weak solvent interaction. The corresponding stibine compound cannot be isolated by the same process, instead [Rh(CO)₂(SbPh₃)₃]⁺ [BF₄]^– (7) is formed when the reaction is carried out in the presence of CO. When reactions designed to prepare [Rh(CO)L₂]⁺ [BF₄]^– are performed in the presence of CO, or [Rh(CO)L₂]⁺ [BF₄]^– complexes are reacted with CO, [Rh(CO)₂L₂]⁺ [BF₄]^– (L = PPh₃, AsPh₃ or PCy₃) (4–6) are formed. If Me₂CO is used as solvent in the preparation of [Rh(CO)L₂]⁺ [BF₄]^– (L = PPh₃ or AsPh₃), then the products are the four-coordinate [Rh(CO)L₂-(Me₂CO)]⁺ [BF₄]^– (8,9) species. The complexes have been characterised by i.r., ³¹P and ¹H n.m.r. spectroscopy and elemental analyses.     

Electrochemical synthesis and magnetic studies of neutral transition metal imidazolates and pyrazolates

Summary The single-step electrochemical synthesis of neutral transition metal complexes of imidazole, pyrazole and their derivatives has been achieved at ambient temperature. The metal was oxidized in an Me₂CO solution of the diazole to yield complexes of the general formula: [M(Iz)₂] (where M = Co, Ni, Cu, Zn; Iz = imidazolate); [M(MeIz)₂] (where M = Co, Ni, Cu, Zn; MeIz = 4-methylimidazolate); [M(PrⁱIz)₂] (where M = Co, Ni, Cu, Zn; PrⁱIz = 2-isopropylimidazolate); [M(pyIz)_n] (where M = Co^III, Cu^II, Zn^II; pyIz = 2-(2-pyridyl)imidazolate); [M(Pz)_n] (where M = Co^III, Ni^II, Cu^II, Zn^II; Pz = pyrazolate); [M(ClPz)_n] and [M(IPz)_n] (where M = Co^III, Ni^II, Cu^II, Zn^II; ClPz = 4-chloropyrazolate; IPz = 4-iodopyrazolate); [M(Me₂Pz)_n] (where M = Co^II, Cu^I, Zn^II; Me₂Pz = 3,5-dimethylpyrazolate) and [M(BrMe₂Pz)_n] (where M = Co^II, Ni^II, Cu^I, Zn^II; BrMe₂Pz = 3,5-dimethyl-4-bromopyrazolate). Vibrational spectra verified the presence of the anionic diazole and electronic spectra confirmed the stereochemistry about the metal centre. Variable temperature (360-90 K) magnetic measurements of the cobalt and copper chelates revealed strong antiferromagnetic interaction between the metal ions in the lattice. Data for the copper complexes were fitted to a Heisenberg (S= ) model for an infinite one-dimensional linear chain, yielding best fit values of J=–62––65cm^–1 andg = 2.02–2.18. Data for the cobalt complexes were fitted to an Ising (S= ) model with J=–4.62––11.7cm^–1 andg = 2.06–2.49.     

A structural study of saturated aqueous solutions of some alkali halides by X-ray diffraction

The structure of nearly saturated or supersaturated aqueous solutions of NaCI [6.18 mol (kg H₂O)^–1], KCI [4.56 mol (kg H₂O)^–1], KF [16.15 mol (kg H₂O)^–1] and CsF [31.96 mol (kg H₂O)^–1] has been investigated by means of solution X-ray diffraction at 25°C. In the NaCI and KCI solutions about 30% and 60%, respectively, of the ions form ion pairs and the Na⁺–Cl^– and K⁺–Cl^– distances have been determined to be 282 and 315 pm, respectively. The average hydration numbers of Na⁺ and Cl^– ions are 4.6 and 5.3, respectively, in the NaCI solution and those of K⁺ and Cl^– ions in the KCI solution are both 5.8. In the KF solution, clusters containing some cations and anions, besides 1:1 (K⁺–F^–) ion pairs, are formed. The K⁺–F^– interatomic distance has been determined to be 269 pm, and nonbonding K⁺...K⁺ and F^–...F^– distances in the clusters are 388 and 432 pm, respectively, and the average coordination numbers n _KF , n _KK and n _FF have been estimated to be 2.3, 1.9, and 1.6, respectively. In the highly supersaturated CsF solution an appreciable amount of clusters containing several caesium and fluoride ions are formed. The Cs⁺–F^– distance in the cluster has been determined to be 312 pm, while the nonbonding Cs⁺...Cs⁺ and F^–...F^– distances are estimated to be 442 and 548 pm, respectively, the distances being about and times the Cs⁺–F^– distance, respectively. The coordination numbers n _CsF , n _CsCs , and n _FF in the first coordination sphere of each ion are 3.3, 2.3 and 5.3, respectively, and the result shows the formation of clusters of higher order than 1:1 and 2:2 ion pairs. These ion pairs and clusters may be regarded as embryos for the formation of nuclei of crystals and the results obtained in the present diffraction study support observations for the nucleation of the alkali halide crystals studied by molecular dynamics simulations previously examined.     

Multicentered bonding and quasi-aromaticity in metal-chalcogenide cluster chemistry

On the basis of the localized molecular orbital (LMO) theory, the bonding schemes for the following types of cluster compounds are briefly reviewed in this paper; the linear [Et₄N][Cl₂FeS₂MoS₂Cu(PPh₃)₂] cluster, triangular trinuclear [M ₃(₃–X)(–Y ₃]⁴⁺ (M = Mo, W;X = O, S;Y = O, S, Se) clusters, triangulated polyhedral clusters: closo-boranes B _n H _n ^2–, octahedral [Co₆(CO)₁₄]^4–, [Ni₂Co₄(CO)₁₄]^2– and [Co₆(₃ –X ₈ ·L ₆ ⁿ⁺ (X = S, Se;L = PPh₃, PEt₃, CO;n = 0,1) as well as quasi-aromatic cluster ligands in cubane-type [Mo₃S₄ ·ML _n ^{(4 +q) +} (M = Mo, W, Fe, Ni, Cu, Sn, Sb;L = Ligand and sandwich-type [Mo₃S₄ ·M · S₄Mo₃]⁸⁺ (M = Mo, Sn, Hg). We put emphasis upon the characteristics of multicentered bonding in these cluster molecules, and, especially, point out existence of a novel species of quasi-aromatic cluster compounds.     

Nonempirical investigation of the influence of the outer-sphere environment on the geometric structure of [AF5] n−

Nonempirical calculations of the electronic structure of the [PF₅]^2– ion and of the clusters [M₅PF₅]³⁺ and [M₄PF₅]²⁺ (M=H⁺, Li⁺, Na⁺) have been carried out. The character of the dependence of the geometric parameters of the [PF₅]^2– ion on the properties and structure of the second coordination sphere has been discussed.Institute of Chemistry, Academy of Sciences of the USSR, Far-Eastern Branch. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 2, pp. 17–22, March–April, 1991.     

Untersuchungen zur Chlorokomplexbildung des Gallium(III)-kations in wäßriger Lösung

Using aqueous GaCl₃ and chloride containing Ga(ClO₄)₃ solutions measurements have been carried out to investigate the formation of complexes with mixed ligands beside the [GaCl₄]^– ion. In contrast to the Raman spectra, which contain only the signals of the [GaCl ₄ ^– ] and the [Ga(H₂O)₆]³⁺ ion, the⁷¹Ga-NMR spectra give clear evidence for the existence of complexes with mixed ligands. Investigations at low temperatures showed their coordination to be octahedral resulting in species [GaCl_n(H₂O)_6–n ]^(3–n)+.     

Extrahierte Verbindungen von Gallium, Indium und Thallium in Verteilungssystemen mit Tributylphosphat, Cyclohexanon und Isobutylmethylketon

Zusammenfassung Das Verteilungsverhalten der Halogenide und Halogenometallate von Gallium, Indium und Thallium mit den drei Solventien (S) Tributylphosphat (TBP), Cyclohexanon (Cyclo) und Isobutylmethylketon (IBMK) wurde untersucht. Die extrahierten Verbindungen wurden nach der Geradenmethode nach Asmus, der logarithmischen Methode nach McKay, der Methode der kontinuierlichen Variation, durch Analyse der beiden Phasen und durch konduktometrische Extraktionstitration nachgewiesen. Identifiziert wurden folgende Verbindungen: [GaCl₄]^–·2 S, Ga-(SCN) ₃·3 TBP, [Ga(SCN)₄]^–·2 TBP, [InCl₄]^–·2 TBP, [InBr₄]^–·2TBP, [InBr₄]·x Cyclo, [InBr₄]^–·x IBMK, [InJ₄]^–·2 S, In(SCN)₃·3 TBP, [In(SCN)₄]^–·2 TBP, TlCl₃·1 TBP, [TlCl₄]^–·2 S, TlBr₃·1 TBP, [Tl-Br₄] ^–·2 S, TlJ₃·x TBP und [TlJ₄]^–·xS. Wegen der nicht eindeutig definierten Oxydationsstufe von Thalliumjodiden ergaben sich bei den Versuchen experimentelle Schwierigkeiten. Daher wurde in diesem System zusätzlich das radioaktive Isotop ²⁰⁴Thallium verwendet.

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Extracted compounds of gallium, indium and thallium in distribution systems with tributyl phosphate, cyclohexanone and isobutylmethylketone

The behaviour of distribution of the halides and halogenometallates of gallium, indium and thallium with the three solvents (S) tributylphosphate (TBP), cyclohexanone (Cyclo) and isobutylmethylketone (IBMK) are investigated. The extracted compounds are detected with the straight-line method of Asmus, the logarithmic method of McKay, the method of continuous variation, by analysis of the two phases, and with the conductometric extraction-titration. The following compounds were identified: [GaCl₄]^–·2S, Ga(SCN)₃·3TBP, [Ga(SCN)₄]^–·2TBP, [InCl₄]^–·2TBP, [InBr₄]^–·2TBP, [InBr₄]·x Cyclo, [InBr₄]^–·x IBMK, [InJ₄]^– ·2S, In(SCN)₃·3TBP, [In(SCN)₄]^–·2TBP, TlCl₃·1TBP, [TlCl₄]^–·2S, TlBr₃ ·1TBP, [TlBr₄]^–·2S, TlJ₃·x TBP and [TlJ₄]^–·x S. The not unequivocally defined stage of oxidation of thallium iodides resulted in experimental difficulties. Thus, in this system the radioactive isotope ²⁰⁴thallium was additionally used.

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Herrn Professor Dr. E. Asmus zum 60. Geburtstag gewidmet.

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Wie danken Herrn Priv.-Doz. Dr. H. Nickel für die freundliche Unterstützung bei den in der KFA Jülich durchgeführten radioaktiven Messungen.     

[N(PPh3)2]2[{Au3Ag2(C2Ph)6} {Au3Cu2(Cu2Ph)6}]: Co-crystallized pentanuclear bimetallic gold-silver and gold-copper clusters

The X-ray structural study of the reaction product of equimolar amounts of [Au₃Cu₂(C₂Ph)₆]. [{Au(C₂Ph)} _n ], and [Ag(C₂Ph)} _n ] revealed two bimetallic anionic [N(PPh₃)₂] + [Au₃Ag₂(C₂Ph)₆]^– and [N(PPh₃)₂]⁺[Au₃Cu₂ (C₂ Pg)₆] — clusters co-crystallized in one asymmetric unit. Each cluster has trigonal bipyramidal geometry with three gold atoms occupying equatorial planes and two silver or copper atoms in the apical positions. Our earlier conclusion based upon spectroscopic characterization describing the product of be above reaction as trimetallic cluster containing three coinage-metals with an overall composition [Au₃CuAg(C₂Ph)₆]^–, was erroneous.Presented at the 210th ACS Meeting, August 19–24, 1995, Chicago, Illinois.     

Die Kristallstruktur von Li4SiO4

Zusammenfassung Die Kristallstruktur des Lithiumorthosilicats wurde mittels dreidimensionaler Fourier-Synthesen und nach der Methode der kleinsten Quadrate bestimmt. Die Gitterparameter der monoklinen Elementarzelle (C _2h ² –P2₁/m) betragen:a=5,14;b=6,10;c=5,30 Å und =90,5°. Die Struktur enthält isolierte [SiO₄]-Tetraeder, welche durch [LiO _n ]-Polyeder (n=4, 5, 6) verknüpft sind. Hervorzuheben ist, daß sämtliche Lithiumlagen nur partiell besetzt sind. Als mittlerer Si–O-Abstand wurde 1,632 Å erhalten; als Mittelwerte der Li–O-Abstände für die verschiedenen Koordinationszahlen ergeben sich: 1,975 [4]; 2,099 [5] und 2,247 [6] Å.

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The crystal structure of lithium orthosilicate has been determined by means of three-dimensional Fourier syntheses and the least squares method. The lattice parameters of the monoclinic unit cell (P2₁/m–C _2h ² ) are:a=5.14;b=6.10;c=5.30 Å and =90.5°. The crystal structure contains isolated [SiO₄]-tetrahedra being connected by [LiO _n ]-polyhedra (n=4, 5, 6). The positions of the lithium atoms are partially occupied only. The average interatomic Si–O distance is found to be 1.632 Å. The averaged values for Li–O distances given for the different coordination numbers are: 1.975 [4]; 2.099 [5] and 2.247 [6] Å.

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Thermodynamics of complexation of zinc(II) with chloride,bromide and iodide ions in hexamethylphosphoric triamide

The complexation of zinc(II) with chloride, bromide and iodide ions has been studied by calorimetry in hexamethylphosphoric triamide (HMPA) containing 0.1 mol-dm^–3 (n-C₄H₉)₄NClO₄ as a constant ionic medium at 25°C. The formation of [ZnX_n]^(2–n)+ (n=1,2,3,4 for X=Cl; n=1,2 for X=Br, I) is revealed, and their formation constants, enthalpies and entropies were determined. It is proposed that the zinc(II) ion is fourcoordinated in HMPA and the coordinating HMPA molecules are stepwise replaced with halide ions to form [ZnX_n(hmpa)_4–n]^(2–n)+ (n=1–4), as is the case for the cobalt(II) ion. Furthermore, the formation of [ZnClI], [ZnBrI], [ZnBrCl] and [ZnBrCl₂]^– is revealed in the relevant ternary systems. It is found that the affinity of a given halide ion X^– to [ZnCl]⁺, [ZnBr]⁺ and [Znl]⁺ is practically the same.     

Studies on transition-metal nitrido and oxo complexes. Part VII(1). Substituted nitrido complexes of osmium and ruthenium

Summary Addition reactions of [MNCl₄]^– (M = Os or Ru) with ligands L or L to give [MNCl₄ · L]^– or [(MNCl₄)₂L]^2– (L = pyridine, pyridine-N-oxide,iso-quinoline or DMSO; L = hexamethylenetetramine, pyrazine or dioxan) are described. With NCO^–, [OsNCl₅]^– gives [OsN(NCO)₅]^2– but NCS^– gives a thionitrosyl complex, [Os(NS)(NCS)₅]^2–. Reactions of OsNCl₃(AsPh₃)₂ with pyridine, 1,10-phenanthroline and tertiary phosphites and phosphinites have been studied, as have reactions of triphenylphosphine with OsOCl₄ andtrans- [MO₂Cl₄]^2– (M = Os or Ru). The nitrido-iodo complexes [OsNI₄]^– and OsNI₃, (SbPh₃)₂ are also reported.     

Komplexe des vierwertigen Nickels mit o-Methylbenzamidoxim

Zusammenfassung Der Komplex des Ni²⁺ mit o-Methylbenzamidoxim (oMB), [Ni(oMB)₂], wurde mit H₂O₂ in Anwesenheit von Cu²⁺ oder unter Luftdurchblasen in alkalischer Lösung mit O₂ zu [Ni(oMB)₄] oxydiert. Die Ligandenzahl und die Bildungskonstante sindn=4 und lgK=7,33. Die Vierwertigkeit des Nickels wurde analytisch nachgewiesen. Die Oxydation verändert dasoMB nicht, wie aus dem IR-Spektrum ersichtlich ist. Die Geschwindigkeitskonstante istk=36,3 l/mol^–1 sec^–1 und entspricht einer bimolekularen Reaktion.

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Complexes of quadrivalent Ni with o-methylbenzamide oxime

The complex of Ni²⁺ with o-methylbenzamide oxime [Ni(oMB)₂] was oxidized to [Ni(oMB)₄] with H₂O₂ in the presence of Cu²⁺ or with O₂ by air-blowing in alkaline solution. The ligand number and the formation constant aren=4 and lgK=7.33, resp. It was proved analytically that nickel is 4-valent. The IR-spectra showed that the oxidation does not attackoMB. The speed constant isk=36.3 l/mole^–1 sec^–1, corresponding to a bimolecular reaction.

     

Kinetic and mechanism of pentacyanohydroxoferrate(III) formation from the reaction of [Fe2HPDTA(OH)2] with cyanide ions

Summary The kinetics and mechanism of exchange of HPDTA in [Fe₂HPDTA(OH)₂] with cyanide ion (HPDTA=2-hydroxytrimethylenediaminetetraacetic acid) was investigated spectrophotometrically by monitoring the peak at 395 nm ( _max of [Fe(CN)₅OH]^3– at pH=11.0±0.02,I=0.25m (NaClO₄) at ±0.1°C).Three distinct observable stages were identified; the first is the formation of [Fe(CN)₅OH]^3–, the second the formation of [Fe(CN)₆]^3– from it and the third the reduction of [Fe(CN)₆]^3– to [Fe(CN)₆]^4– by HPDTA^4– released in the first stage.The first stage follows first-order kinetics in [Fe₂HPDTA(OH)₂] and second-order in [CN^–] over a wide range of [CN^–], but becomes zero order at [CN^–]<5×10^–2 m. We suggest a cyanide-independent dissociation of [Fe₂HPDTA)(OH)₂] into [FeHPDTA(OH)] and [Fe(OH)]²⁺ at low cyanide concentrations and a cyanide-assisted rapid dissociation of [Fe₂HPDTA(OH)₂] to [FeHPDTA(OH)(CN)]^3– and [Fe(OH)]²⁺ at higher cyanide concentrations. The excess of cyanide reacts further with [FeHPDTA(OH)(CN)]^3– finally to form [Fe(CN)₅OH]^3–.The reverse reaction between [Fe(CN)₅OH]^3– and HPDTA^4– is first-order in [Fe(CN)₅OH]^3– and HPDTA^4–, and exhibits inverse first-order dependence on cyanide concentration.A six-step mechanism is proposed for the first stage of reaction, with the fifth step as rate determining.     

A voltammetric identification of complex species inDMF solutions of Iron(III) complexes with salicylaldehydeS-methylthiosemicarbazone

The complex species existing under voltammetric conditions (0.1 mol dm^–3 LiCl) inDMF solutions of several iron(III) complexes with salicylaldehydeS-methylthiosemicarbazone (H₂ L) have been identified by adding [FeCl₄]^– and H⁺ and recording voltammograms at a glassy carbon electrode, both in stationary and rotating mode. By the action of Cl^–, a ligand release occurs, and the bis(ligand) cation [Fe(HL)₂]⁺ is transformed into [Fe(HL)Cl₃]^–. The same species is obtained in the reaction of [FeL ₂]^– with [FeCl₄]^–. Besides, the possibility has been demonstrated to obtain some complexes (and finally [FeCl₄]^–) starting from a more basic type, by a careful addition of H⁺ generatedin situ from a Pd/H electrode. A practical application of the latter procedure could be the determination of the iron(III) content in such and similar compounds.

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Die voltammetrische Identifizierung der Komplex-Spezies in DMF Lösungen von Eisen(III) Komplexen mit Salicylaldehyd-S-methylthiosemicarbazon

Zusammenfassung Die Spezies, die unter voltammetrischen Bedingungen (0.1 mol dm^–3 LiCl) inDMF Lösungen einiger Eisen(III)-Komplexe mit Salizylaldehyd-S-methylthiosemicarbazon (H₂ L) vorhanden sind, wurden durch Zusatz von [FeCl₄]^– und H⁺ und Aufnahme von Voltammogrammen an der stationären und rotierenden Glaskohlenstoffelektrode identifiziert. Unter der Wirkung von Cl^–-Ionen kommt es zu einem Ligandenaustausch, wobei das bis(Ligand)-Kation [Fe(HL)₂]⁺ in [Fe(HL)Cl₃]^– übergeht. Die gleiche Substanz erhält man bei der Reaktion von [FeL ₂]^– mit [FeCl₄]^–. Ferner wird die Möglichkeit der Gewinnung einiger Komplexe (schließlich von [FeCl₄]^–) ausgehend von der basischen Form durch stufenweise Zugabe von H⁺-Ionen, diein situ mit Hilfe einer Pd/H-Elektrode gebildet werden, beschrieben. Eine praktische Anwendung des letztgenannten Prozesses wäre die Bestimmung des Gehalts von Fe(III) in Lösungen der genannten und ähnlichen Komplexverbindungen.

     

Hexamethylphosphorsäuretriamid als Ligand, 3. Mitt.: Umsetzungen von [Co(HMPT)4]2+ mit Rhodanid-, Cyanid- und Azidionen

Zusammenfassung Auf Grund spektrophotometrischer, potentiometrischer und konduktometrischer Befunde entstehen aus [Co(HMPT)₄]²⁺ in Hexamethylphosphorsäuretriamid (HMPT) bei Zusatz von Pseudohalogenidionen folgende Koordinationsformen: [Co(HMPT)₃N₃]⁺, [Co(HMPT)₂(N₃)₂], [Co(HMPT)(N₃)₃]^–, [Co(N₃)₄]^2–, [Co(HMPT)₃NCS]⁺, [Co(HMPT)₂(NCS)₂], [Co(HMPT)(NCS)₃]^–, [Co(NCS)₄]^2–, [Co(HMPT)₂(CN)₂], [Co(HMPT)(CN)₃]^–, [Co(HMPT)(CN)₅]^3–.

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Hexamethyl phosphoric triamide as a ligand, III: Reactions of [Co(HMPT)₄]²⁺ with rhodanide, cyanide, and azide ions, resp

Spectrophotometric, potentiometric and conductometric results indicate that addition of pseudohalide ions to [Co(HMPT)₄]²⁺ in hexamethylphosphoramide (HMPT) leads to the following coordination forms: [Co(HMPT)₃N₃]⁺, [Co(HMPT)₂(N₃)₂], [Co(HMPT)(N₃)₃]^–, [Co(N₃)₄]^2–, [Co(HMPT)₃NCS]⁺, [Co(HMPT)₂(NCS)₂], [Co(HMPT)(NCS)₃]^–, [Co(NCS)₄]^2–, [Co(HMPT)₂(CN)₂], [Co(HMPT)(CN)₃]^–, [Co(HMPT)(CN)₅]^3–.

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2. Mitt.:V. Gutmann undA. Weisz, Mh. Chem.100, 2104 (1969).     

Äthylensulfit als Lösungsmittel, 1. Mitt.: Halogenokomplexe von Kobalt (II)

Zusammenfassung Die Bildung von Chloro-, Bromo- und Jodokomplexen von Co²⁺ wurde in Äthylensulfit (ES) auf spektrophotometrischem, potentiometrischem und konduktometrischem Wege untersucht. Folgende Komplexformen dürften gebildet werden: [CoCl(ES)₅]⁺, CoCl₂(ES)₂, [CoCl₃ ES]^–, [CoCl₄]^2–, [CoBr(ES)₅]⁺, CoBr₂(ES)₂, [CoBr₄]^2– und [CoJ₄]^2–. Die Ergebnisse werden hinsichtlich der des Lösungsmittels und des sterischen Baues des Lösungsmittelmoleküles mit denen in anderen Lösungsmitteln verglichen und diskutiert.

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Reactions involving the formation of complex species of Co²⁺ with chloride, bromide and iodide ions have been investigated by spectrophotometric, potentiometric and conductometric methods using ethylene sulphite (ES) as solvent. The following complexes appear to be formed: [CoCl(ES)₅]⁺, CoCl₂(ES)₂, [CoCl₃ ES]^–, [CoCl₄]^2–, [CoBr(ES)₅]⁺, CoBr₂(ES)₂, [CoBr₄]^2– and [CoI₄]^2–. The influence of the donor number of the solvent and steric contributions by the solvent molecules are discussed.

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Spatial structure and thermodynamic aspects of Dy(III) complex formation with some mono- and dicarboxylic acids

Spatial structures of complexes [DyAc]²⁺, [DyBz]²⁺, [DyAc₂]⁺ and [DyBz₂]⁺ in aqueous solutions (Ac^– and Bz^–, acetate and benzoate anions, respectively) are studied using the paramagnetic double refraction method. The polyhedra of [DyAc(H₂O)₆]²⁺ and [DyBz(H₂O)₆]²⁺ are dodecahedra with ligands coordinated at one of the edges. In the complexes [DyAc₂(H₂O)₄]⁺ and [DyBz₂(H₂O)₄]⁺ the ligands are coordinated at the edges of a square antiprism at an angle of 50 (55)° to the local symmetry axis of higher symmetry.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1038–1040, June, 1993.     

[RhCl(CO)(PPh3)]2. A precursor for the synthesis of cationic rhodium complexes with nitrogen donor ligands

Summary The use of [RhCl(CO)(PPh₃)]₂ as a precursor for the synthesis of complexes of the types [Rh(CO)L₂(PPh₃)]A (A = [ClO₄]^– or [BPh₄]^–; L = pyridine type ligand) and [Rh(CO)(L-L)(PPh₃)]A (A = [ClO₄]^– or [BPh₄]^–; L-L = bidentate nitrogen donor) and the preparation of several complexes of the types [Rh(CO)L(PPh₃){P(p-RC₆H₄)₃}]BPh₄ and [Rh(CO)(phen)(PPh₃){P(p-RC₆H₄)₃}]A (A = [ClO₄]^– or [BPh₄]^–; R = H or Me) is described.Author to whom all correspondence should be directed.