Einstieg in die Chemie einfacher Rhenium-Schwefel-Komplexe und -Cluster. Darstellung und Kristall-Struktur von R[ReS4], R′[ReS9], (NH4)4[Re4S22]·2H2O,R′2[Cl2Fe(MoS4)FeCl2]x [Cl2Fe(ReS4)FeCl2]1-x′ R′2 [(ReS4)Cu3l4] und RR′2[(ReS4)Cu5Br7] (R  NEt4; R′  PPh4; x = 0,3, 0,5)

Entry to the Chemistry of Simple Rhenium Sulfur Complexes and Clusters. Preparation and Crystal Structures of R′[ReS₄], R′[ReS₉], (NH₄)₄[Re₄S₂₂]·2H₂O, R′₂[Cl₂Fe(MoS₄)FeCl₂]_1-x, R′₂[(ReS₄)Cu₃I₄] and RR′₂[(ReS₄)Cu₅Br₇] (R ? NEt₄; R′ ? PPh₄, x = 0.3, 0.5) The compounds R[ReS₄] ( 1 ), R′[ReS₉] ( 2 ), (NH₄)₄[Re₄S₂₂]·2 H₂O ( 3 ), R′₂[Cl₂Fe(MoS₄) FeCl₂]_x[Cl₂Fe(ReS₄)FeCl₂] _1-x (x = 0.3 ( 4 ), 0.5), R′₂[(ReS₄)Cu₃I₄] ( 5 ) and R′₂[(ReS₄)Cu₅Br₇] ( 6 ) (R ? NEt₄; R′ ? PPh₄) have been prepared by reaction of perrhenates or rhenium(VII)oxide with S_x^2? solutions (under different conditions) or by reactions of metal-halides with [ReS₄]^?-ions. All compounds have been characterized by complete X- ray structure analysis. For further details see Inhaltsübersicht.     

FT-IR spectra and normal coordinate analysis of the [Cl2FeS2MoS2FeCl2]2− dianion

The FT-IR spectra of the [Cl₂FeS₂MoS₂FeCl₂]^2? dianion were measured in the range 500 to 100 cm^?1. A simplified general valence force field was used in a normal coordinate analysis. The calculated frequencies agree well with the observed values, with a mean deviation of less than 1.0%, thus confirming the assignments of the vibrational spectrum. Altogether 16 force constants, including stretching, bending, torsion and stretching-stretching interactions were obtained. The rationality and the reliability of the results were discussed.     

Thiochloroanionen von Molybdän(IV). Die Kristallstruktur von (NEt4)3[Mo3(μ3-S)(μ-S2)3Cl6]Cl · CH2Cl2 Kristallstruktur,EPR-Spektrum und magnetische Eigenschaften von (NEt4)2[Mo2(μ-S2)(μ-Cl)2Cl6]

Thiochloro Anions of Molybdenum (IV). Crystal Structure of (NEt₄)₃[Mo₃(μ₃-S)(μ-S₂)₃Cl₆]Cl μ CH₂Cl₂. Crystal Structure, Magnetic Properties, and EPR-Spectrum of (NEt₄)₂ [Mo₂(μ-S₂)(μ-Cl)₂Cl₆] From molybdenum pentachloride and tetraethylammonium hydrogensulfide in CH₂Cl₂ an insoluble product of composition (NEt₄)₂[Mo₂S₃Cl₉] was obtained along with a brown solution, from which (NEt₄)₂[Mo₂(S₂)Cl₈] was crystallized. The insoluble product and NEt₄Cl react in CH₂Cl₂ to yield, among others, (NEt₄)₃[Mo₃(S)(S₂)₃Cl₆]Cl · CH₂Cl₂. The latter crystallizes in the orthorhombic space group Pnma, a = 2495.8, b = 1501.2, c = 1295.6 pm, Z = 4. According to the crystal structure determination (3070 observed reflexions, R = 0.049) the [Mo₃(S)(S₂)₃Cl₆]^2? ion consists of an Mo₃ triangle with Mo? Mo bonds, each side of the triangle is bridged by disulfido groups and one sulfur atom is capped over the Mo₃ triangle; the single chloride ion is looseley associated to three S atoms. (NEt₄)₂[Mo₂(S₂)Cl₈] also crystallizes in the space group Pnma, a = 1425.6, b = 1129.9, c = 2004.7 pm, Z = 4; structure determination with 1703 observed reflexions, R = 0.061. In the [Mo₂(S₂)Cl₈]^2? ion the Mo atoms are bridged via one disulfido group and two chlorine atoms. There is a Mo? Mo bond, but according to the magnetic properties and the EPR spectrum each Mo atom still possesses one unpaired electron.     

Thiohalogeno-Verbindungen von Niob und Tantal: NbSCl3, TaSCl3, [NbSCl5]2−, [TaSCl5]2−, [NbSBr4]− Die Kristallstrukturen von (PPh4)2[NbSCl5] · 2 CH2Cl2 und NEt4[NbCl6]

Thiohalo Compounds of Niobium and Tantalum: NbSCl₃, TaSCl₃, [NbSCl₅]^2?, [TaSCl₅]^2?, [NbSBr₄]^?. Crystal Structures of (PPh₄)₂[NbSCl₅] · 2 CH₂Cl₂ and NEt₄[NbCl₆] NbSCl₃ can be obtained from NbCl₅ by reaction with H₂S or bistrimethylsilyl sulfide in a suspension of CCl₄ or CH₂Cl₂, respectively; in the latter case the product contains a rest of trimethylsilyl groups. This also applies for TaSCl₃, NbSBr₃ and TaSBr₃, which are formed from the metal pentahalides and S(SiMe₃)₂. NEt₄[NbSCl₄] is formed together with NEt₄[NbCl₆] in the reaction of NbCl₅ with NEt₄SH in CH₂Cl₂. PPh₄[NbCl₆] reacts with S(SiMe₃)₂ in dichloromethane yielding (PPh₄)₂[NbSCl₅] · 2 CH₂Cl₂, whereas PPh₄[NbSBr₄] is obtained from PPh₄[NbBr₆] and S(SiMe₃) under the same conditions. (PPh₄)₂[TaSCl₅] · 2 CH₂Cl₂ was obtained from TaSCl₃ and PPh₄Cl in CH₂Cl₂. According to an X-ray crystal structure determination (PPh₄)₂[NbSCl₅] · 2 CH₂Cl₂ crystallizes in the β-(AsPh₄)₂[UCl₆] · 2 CH₂Cl₂ type with positionally disordered, octahedral anions. Crystal data: a = 1 021.7, b = 1120.4, c = 1 243.3 pm, α = 70.77, β = 80.24, γ = 80.54°, space group P1 , Z = 2; 2462 unique observed reflexions, R = 0.036. NEt₄[NbCl₆] crystallizes isotypic to NEt₄[WCl₆], a = 723.5, b = 1 018.0, c = 1 174.6 pm, β = 100.07°, space group P2₁/n, Z = 2; 1 875 reflexions, R = 0.075.     

Determination of copper(I)-ethylene complexes, [Cu(C2H4)]+ and [Cu(C2H4)2]+, with aid of EDTA titration of copper(I) and copper(II) ions

Summary Volumetric measurements of ethylene and simple EDTA titration of copper(I) and copper(II) ions confirm that [CuL]⁺ and [CuL₂]⁺ are formed when an aqueous solution of copper(II) is reduced by copper metal in the presence of ethylene, (L). The formation constants,K ₁=[CuL⁺]²[Cu²⁺]^–1[L]^–2 andK ₂=[CuL ₂ ⁺ ]^–1[L]^–1, have been estimated. The formation of [CuL]⁺ is accompanied by an enthalpy change, H, of –25 kJ mol^–1, and a positive entropy change, S, of 13 J mol^–1 K^–1.     

Thiochlorowolframate von Wolfram(V) und -(VI). Die Kristallstrukturen von PPh4[WSCl4] und (PPh4)2[WS2Cl4] · 2 CH2Cl2

Thiochlorowolframates with Tungsten(V) and (VI). Crystal Structures of PPh₄[WSCl₄] and (PPh₄)₂[WS₂Cl₄] · 2 CH₂Cl₂ Diamagnetic (NEt₄)₂[WSCl₄]₂, having tungsten atoms linked via sulfur atoms, is obtained by the reaction of WCl₅ with NEt₄SH as well as by the reduction of WSCl₄ with NEt₄I in dichloromethane. If the reduction is performed with PPh₄I, PPh₄[WSCl₄] with monomer anions is formed. Reaction of WCl₆ with H₂S in dichloromethane yields brown, insoluble WS₂Cl₂ which has terminal W?S groups and bridging W? S? W groups according to its IR spectrum. WS₂Cl₂ and PPh₄Cl react to afford PPh₄[WS₂Cl₃] · 2 CH₂Cl₂ and (PPh₄)₂[WS₂Cl₄] · 2 CH₂Cl₂. IR spectra are reported. The crystal structures of PPh₄[WSCl₄] and (PPh₄)₂[WS₂Cl₄] · 2 CH₂Cl₂ were determined by X-ray diffraction. PPh₄[WSCl₄]: tetragonal, space group P4/n, Z = 2, a = 1292.3 pm, c = 763.2 pm; R = 0.054 for 898 observed reflexions. The [WSCl₄]^? ion has the structure of a square pyramid with a rather short W?S bond of 206 pm length. (PPh₄)₂[WS₂Cl₄] · 2 CH₂Cl₂: triclinic, space group P1 , a = 1017.7, b = 1114.5, c = 1243.4 pm, α = 70.61, β = 79.73, γ = 80.80°; R = 0.076 for 1804 reflexions. The [WS₂Cl₄]^2? has cis configuration; as it is situated on an inversion center it shows positional disorder.     

Syntheses,crystal structures and magnetic properties of two cyano-bridged two-dimensional assemblies [Fe(salpn)]2 [Fe(CN)5NO] and [Fe(salpn)]2[Ni(CN)4]

Two cyano-bridged assemblies, [Fe^III(salpn)]₂[Fe^II(CN)₅NO] (1) and [Fe^III (salpn)]₂[Ni^II(CN)₄] (2) [salpn = N, N-1,2-propylenebis(salicylideneiminato)dianion], have been prepared and structurally and magnetically characterized. In each complex, [Fe(CN)₅NO]^2– or [Ni(CN)₄]^2– coordinates with four [Fe(salpn)]⁺ cations using four co-planar CN^– ligands, whereas each [Fe(salpn)]⁺ links two [Fe(CN)₅NO]^2– or [Ni(CN)₄]^2– ions in the trans form, which results in a two-dimensional (2D) network consisting of pillow-like octanuclear [—M^II—CN—Fe^III—NC—]₄ units (M = Fe or Ni). In complex (1), the NO group of [Fe(CN)₅NO]^2– remains monodentate and the bond angle of Fe^II—N—O is 180.0°. The variable temperature magnetic susceptibilities, measured in the 5–300 K range, show weak intralayer antiferromagnetic interactions in both complexes with the intramolecular iron(III)iron(III) exchange integrals of –0.017 cm^–1 for (1) and –0.020 cm^–1 for (2), respectively.     

(PPh4)[(ReO2S2)CuI] und (NEt4)2[(ReOS3)Cu3Cl4]: Fixierung der bisher nicht isolierten Ionen [ReO2S2]− und [ReOS3]− durch Ausnutzung der Stabilität der CuS2(Re)- und Cu3S3(Re)-Fragmente

(PPh₄)[(ReO₂S₂)CuI] and (NEt₄)₂[ReOS₃)Cu₃Cl₄]: Fixation of the up to now not Isolated Ions [ReO₂S₂]^? and [ReOS₃]^? Utilizing the Stability of the CuS₂(Re) and Cu₃S₃(Re) Fragments (PPh₄)[(ReO₂S₂)CuI] ( 1 ) and (NEt₄)₂[ReOS₃)Cu₃Cl₄] ( 2 ) containing the up to now not isolated oxothioperrhenate ions [ReO₂S₂]^? and [ReOS₃]^? as ligands, have been prepared by the reaction of (NEt₄)[ReS₄] with PPh₃ and CuI in acetone in the presence of (PPh₄)I (( 1 )) or with CuCl in CH₂Cl₂ in the presence of (NEt₄)Cl (( 2 )), respectively. 1 and 2 have been characterized by X-ray structure analysis, elemental analysis and spectroscopic studies (IR, UV/Vis). The electronic spectra show bands which can approximately be assigned to interesting low-energy charge-transfer-transitions of the type d(Cu) → d(Re). For crystal data see Inhaltsübersicht.     

Crystal structures of the organic metals (ET)2[Hg(SCN)Cl2] and (ET)2[Hg(SCN)2Br]

The compositions and structures of two new organic metals based on ET [where ET = bis(ethylenedithio)tetrathiafulvalene], viz., (ET)₂[Hg(SCN)Cl₂], with a metal-dielectric transition temperature (T_m-d) of 35°K, and (ET)₂[Hg(SCN)₂Br], with T_m-d = 140°K, were established by x-ray diffraction analysis. The crystal structures of the investigated compounds are similar to the structure of the previously studied organic metal (ET)₂[Hg(SCN)₂Cl] with T_m-d = 50°K. The principal crystallographic data for (ET)₂[Hg(SCN)Cl₂] are as follows: a = 36.64(1), b = 8.300(4), c = 11.798(1) Å, = 89.91(3)°, V = 3588.1(9) ų, space group Cc, Z = 4, d_calc = 2.05 g/cm³. The principal crystallographic data for (ET)₂[Hg(SCN)₂Br] are as follows: a = 37.088(14), b = 8.338(3), c = 11.738(5) Å, = 89.71(3)°, V = 3629.6(8) ų, space group C2/c, Z = 8, d_calc = 2.15 g/cm³. A characteristic feature of the crystal structure of the investigated compounds is alternation of the anion and cation layers along the a axis of the crystal. In the cation layer of the k type the ET are interconnected by shortened S...S intermolecular contacts (3.39–3.58 Å). The [Hg(SCN)_3–nX_n]^– anions (X = Cl, Br; n = 1, 2) form polymeric chains with one or two bridged SCN groups. A tendency for a decrease in the metal-dielectric transition temperature with a decrease in the volume of the anion is detected in the (ET)₂[Hg(SCN)_3–nX_n] salts, where X = Cl and Br, and n = 1 and 2.Institute of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2323–2331, October, 1992.     

Die Reaktion von Trichlornitromethan mit Eisencarbonylen Kristallstruktur von (PPh4)2[Fe2OCl6] · 2 CH2Cl2

Reaction of Trichloronitro Methane with Iron Carbonyls. Crystal Structure of (PPh₄)₂[Fe₂OCl₆] · 2 CH₂Cl₂ Trichloronitro methane reacts with Fe₂(CO)₉ or Fe₃(CO)₁₂ forming NO[FeOCl₂] which is composed of Nitrosyl ions and polymeric [FeOCl₂]^?. The reaction of NO[FeOCl₂] with POCl₃ affords Fe(O₂PCl₂)₃; with tetraphenyl phosphoniumchloride it forms the complex (PPh₄)₂[Fe₂OCl₆] which is soluble in CH₂Cl₂. The oxochloro ferrates are characterized by the aid of ⁵⁷Fe-Mössbauer spectra and by i.r. spectra. A single crystal of (PPh₄)₂[Fe₂OCl₆] · 2 CH₂Cl₂ was used to carry out a structural investigation by means of X-ray diffraction data (space group P1 , Z = 1, a = 1157.2(2), b = 1363.8(3), c = 1140.3(2) pm, α = 109.22(1)°, β = 95.23(1)°, γ = 67.24(2)°, R = 0.052 for 3814 reflexions with F₀ > 3σ). The [Cl₃Fe? O? FeCl₃]^2?-anion is found to have a centre of symmetry and thus, in accordance with the i.r. spectra, contains a linear bridge. High thermal parameters of the bridging oxygen atom and the chlorine ligands, however, allow interpretations as orientation disorder of slightly bent anions.     

Molecular architecture of copper (I) thiometallates: synthesis and characterization of [ReS4Cu3Cl5]3-, a geometry derived from the single cubane-like structure

The new rhenium-copper heteronuclear complex [NEt₄]₃[ReS₄C₃Cl₅]2, was obtained as black crystals in 65% yield, from the reaction of [NEt₄[[ReS₄], [NEt₄][CuCl₂], and [NEt₄][Cl] at - 20°C in acetone, while at room temperature without additional chloride [NEt₄]₂[ReS₄Cu₃Cl₄]1 crystallized as black crystals in 60% yield. Crystal data for2: space group Pl,a=10.331(4) A,b=14.261(2) A,c= I4.458(3) A, =78.55(1)°, =81.83(3)°, =83.66(3)°,Z=2, 6480 reflections;R=0.058. For1: space group C2/c,a=20.969(5)A,b=12.955(5)A,c=22.827(8)A, =91.16(2)°, Z=8, 3208 reflections,R = 0.052, The geometry of2 can be viewed as restllting from the opening of the cubane-like structure of1.     

Synthesis and crystal structure of tetraethylammonium-μ-trichloro-heptachloro-diaqua-trirhenate(III)-dihydrate,NEt4[Re3Cl10(H2O)2] · 2 H2O

NEt₄[Re₃Cl₁₀(H₂O)₂] · 2 H₂O ( 1 ) was obtained from hydrochloric acid solutions of ReCl₃ and tetraethylammonium chloride, NEt₄Cl, by isothermal evaporation as dark red crystals. 1 crystallizes in the orthorhombic crystal system, space group Pnma, Z = 4, with a = 1838,7(2), b = 1456.9(1), c = 972.08(7) pm, V_m = 391.81(6) cm³ · mol^?l. The crystal structure consists of [Re₃Cl₁₀(H₂O)₂]^? anions that are arranged in the fashion of a hexagonal closest-packing of spheres. These are held together by partially disordered NEt₄⁺ cations and are bound into a hydrogen bonding system with the crystal water.     

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.

     

The outersphere complex of EuCl2+ in a mixed system of methanol and water of 1.0M (H, Na) (Cl, ClO4)

The stability constans, ₁, of each monochloride complex of Eu(III) have been determined in the methanol and water mixed system with 1.0 mol·dm^–3 ionic strength using a solvent extraction technique. The values of ₁ increase with an increase in the mole fraction of methanol (X _S ) in the mixed solvent system when 0X _S 0.40. The, distance of Eu³⁺–Cl^– in the mixed solvent system was calculated using the Born-type equation and the Gibbs' free energy derived from ₁. Calculation of the Eu³⁺–Cl^– distance and the preferential solvation, of Eu³⁺ by water proposed the variation of the outersphere complex of EuCl²⁺ as follows: (1) [Eu(H₂O)₉]³⁺Cl^–, [Eu(H₂O)₈]³⁺Cl^– and [Eu(H₂O)₇(CH₃OH)³⁺Cl^– inX _S0.014, (2) [Eu(H₂O)₈]^3–Cl^– and [Eu(H₂O)₇(CH₃OH)]³⁺Cl^– in 0.014<X _S <0.25 and (3) [Eu(H₂O)₇(CH₃OH)]^3–Cl^– and [Eu(H₂O)₆(CH₃OH)[₂ ³⁺Cl^– in 0.25<X _S 0.40.     

Synthesis,crystal structure and magnetic properties of a two-dimensional mixed-valence assembly [Fe(salen)]2[Fe(CN)5NO]

A cyanide-bridged Fe^III–Fe^II mixed-valence assembly, [Fe^III(salen)]₂[Fe^II(CN)₅NO] [salen = N,N-ethylenebis(salicylideneiminato)dianion], prepared by slow diffusion of an aqueous solution of Na₂[Fe(CN)₅NO] · 2H₂O and a MeOH solution of [Fe(salen)NO₃] in an H tube, has been characterized by X-ray structure analysis, i.r. spectra and magnetic measurements. The product assumes a two-dimensional network structure consisting of pillow-like octanuclear [—Fe^II—CN—Fe^III—NC—]₄ units with dimensions: Fe^II—C = 1.942(7) Å, C—N = 1.139(9) Å, Fe^III—N = 2.173(6) Å, Fe^II—C—N = 178.0(6)°, Fe^III—N—C = 163.4(6)°. The Fe^II—N—O bond angle is linear (180.0°). The variable temperature magnetic susceptibility, measured in the 4.8–300 K range, indicates the presence of a weak intralayer antiferromagnetic interaction and gives an Fe^III–Fe^III exchange integral of –0.033 cm^–1.     

Die Reaktionen von Eisen(III)-chlorid mit Trithiazylchlorid. Die Kristallstruktur von [S4N4Cl]+[FeCl4]⊖

Reactions of Iron Trichloride with Trithyazyl Chloride. Crystal Structure of [S₄N₄Cl]⁺[FeCl₄]^? Iron trichloride reacts with (NSCl)₃ yielding S₄N₄[FeCl₄]₂, S₃N₃Cl₂[FeCl₄] or S₄N₄Cl[FeCl₄], depending on the reaction conditions. The i.r. spectra prove the presence of [FeCl₄]^? ions for all three compounds. The ⁵⁷Fe-Mössbauer spectra show a slight quadrupole splitting at 80 K for S₃N₃Cl₂[FeCl₄] (ΔE^Q = 0.42 mm · s^?1) and S₄N₄Cl[FeCl₄] (ΔE^Q = 0.23 mm · s^?1), which indicates a slight deformation of the FeCl₄^? tetrahedra. The crystal structure of S₄N₄Cl[FeCl₄] was determined and refined with X-ray diffraction data (2549 independent reflexions, R = 0.026). S₄N₄Cl[FeCl₄] crystallizes in the triclinic space group P1 with two formula units per unit cell. The lattice constants are a = 712, b = 911, c = 1006 pm, α = 76.5°, β = 83.8° and γ = 80.5°. The structure consists of the so far unknown [S₄N₄Cl]^⊕ cations and slightly deformed FeCl₄^? ions. The [S₄N₄Cl]^⊕ ion consists of a S₄N₄ ring built up of two nearly planar S₃N₂ fragments having a dihedral angle of 136°. The average SN bond length is 157 pm, the SCI bond length 214 pm.     

Kinetics and mechanisms of homogeneous catalytic reactions. Part 3. Regioselective,catalysed [RuH(CO)(NCMe)2(PPh3)2]BF4 reduction of quinoline

Summary A kinetic study of the regioselective homogeneous hydrogenation of quinoline (Q) to 1,2,3,4-tetrahydroquinoline (THQ) was carried out using the cationic complex [RuH(CO)(NCMe)₂(PPh₃)₂]BF₄ (1) as the precatalyst. The experimentally determined rate law wasr = {k ₂ K ₁/(1+K ₁[H₂])}[Ru₀][H₂]², which becomesr = {k ₂ K ₁[Ru₀]–[H₂]² at low hydrogen concentrations (k ₂ K ₁ = 28.5M ^–2 s^–1 at 398 K). The corresponding activation parameters were found to be H = 42 + 6 kJ mol^–1, S = – 115 ± 2JK^–1mol^–1 and G = 92 ± 8 kJ mol^–1. Complex(1) was found to react with Q in CHCl₃ under reflux to yield [RuH(CO)(NCMe)(N-Q)(PPh₃)₂]BF₄ (2) which was also isolated from the hydrogenation runs. These experimental findings, together with the results ofab initio self-consistent-field molecular orbital calculations on the free organic molecules involved, are consistent with a mechanism involving a rapid and reversible partial hydrogenation of(2) to yield the corresponding dihydroquinoline (DHQ) species [RuH(CO)(NCMe)(DHQ)(PPh₃)₂]BF₄ (4), followed by a rate-determining second hydrogenation of DHQ to yield [RuH(CO)(NCMe)(THQ)(PPh₃)₂]BF₄ (3).     

Luminescence of salts and copolymers containing the (MoII6Cl8)4+ cluster

The photophysical properties (absorption, emission) of the (Bu₄N)₂[(Mo^II ₆Cl₈)L₆] (L = CF₃COO^–, CH₂=CHCOO^–) cluster salts and (Bu₄N)₂[(Mo^II ₆Cl₈)(CF₃COO)_6–n]—polyacrylic acid copolymers were studied. Both the cluster-containing monomers and corresponding copolymers phosphoresce intensely ( 0.2—0.4 ms at 77—300 K).     

Na3Fe2S4, ein Thioferrat mit gemischt valenter sk∞/1[FeS2]-Kette

Na₃Fe₂S₄ has been prepared from Na₂S, S and Fe. It crystallizes in space group Pnma,a=6.6333 (5) Å,b=10.675 (1) Å,c=10.677 (2) Å,Z=4. The crystal structure, as determined from single crystal four-circle diffractometer data (R=2.8%), consists of sk/1[FeS₂]-chains formed by slightly distorted edge sharing [FeS₄]-tetrahedra, the iron atoms having a formal valency of +2.5. The sodium ions are approximately octahedrally coordinated. Exposed to air, Na₃Fe₂S₄ readily takes up water to form a hydrate by a pertially topochemical reaction.

     

Crystal structure determination and properties of hydrogen hexacyanododeca-μ-chloro-octahedro-hexatantalate(4−)-Dodecahydrate

Summary The cluster compound H₄[Ta₆Cl₁₂(CN)₆] · 12H₂O was prepared and identified by potentiometric titrations, i.r. and visible spectra and by three-dimensional single-crystal x-ray diffraction methods. Discrete [Ta₆Cl₁₂(CN)₆]^4– ions contain a linear Ta–CN unit with Ta–C=2.21(4) and C–N=1.16(5) Å, respectively. Each nitrogen atom is hydrogen bonded [2.63(12)Å] to two oxygen atoms.