The thermal dissociation of the [Co(en)3](SCN)3 and [Co(en)3]I3 complexes

The thermal dissociation of the [Co(en)₃](SCN)₃ and [Co(en)₃]I₃ complexes was studied by thermogravimetry, differential thermal analysis, thermomagnetic analysis, pyrolytic techniques, evolved gas analysis, and mass spectrometry, in vacuo and nitrogen atmospheres. It was found that the [Co(en)₃](SCN)₃ complex dissociated in four steps:

It was not possible to elucidate the intermediate compounds formed in the thermal dissociation of the [Co(en)₃]I₃ complex.     

The thermal dissociation of the [Co(NH3)6]Cl3 and [Co(NH3)6]Br3 complexes in vacuo

The thermal dissociation of the complexes, [Co(NH₃)₆]X₃(X^?=Cl, Br), was studied in vacuo using the techniques of thermogravimetry, evolved gas analysis and mass spectrometric analysis. It was found that the reaction stoichiometry was identical to that previously determined in air but that the type of intermediate compounds formed were different. The dissociation occurred by the reactions:

     

Specific syntheses and electrochemistry of isomeric [Mn(CO)6-n(CNMe)n] (n = 3, 4) complexes

1'1,-Ferrocenediacetic acid anhydride has been prepared and it has been shown to be useful in the preparation of new heteroannularly substituted ferrocenyl-penicillins and -cephalosporins; these compounds exhibit antibiotic activity.     

Anomalous electronic energy partitioning in Mg*(3p) + (F2, Cl2) and Ca*(3P) + Cl2 reactions

Absolute cross sections were measured for beam attenuation, MX⁺(¹Σ_g⁺) chemiionization and MX(A²Π) chemiluminescence. The latter disagree strikingly with predictions based on adiabatic correlations. Information theoretic analysis shows some channels to be statistically, other highly non-statistically populated. A qualitative MO model is in accord with these findings.     

Darstellung und chemie von Me2TlN(SiMe3)2 und Tl[N(SiMe3)2]3

The complexes [Rh(η³-C₃H₄R)(η⁵-C₅R′₅)L]⁺BF₄^- (R  1-Me, R′  H, Me; R  2-Me, R′  H) (L  C₅H₅N, Ph₃P, Ph₃As) have been prepared from Rh(η³-C₃H₄R)(η⁵-C₅R′₅)Cl and AGBF₄ in acetone, followed by reaction with the stoicheiometric quantity of L. The ¹H and ¹³C NMR spectra of the salts are reported and discussed.     

Three-coordinate RhX[P(C6H11)3]2, their reactions with N2 and O2, and the trans-influence in RhX[P(C6H11)3]2L (X = anionic,L = neutral ligand)

Three-coordinate RhX(PCy₃)₂ complexes (X = F, Cl, Br, I; Cy = cyclohexyl) have been prepared from rhodium(I) cyclooctene compounds. RhCl(PCy₃)₂ is in equilibrium with its dimer. The complexes RhX(PCy₃)₂ (X = Cl, Br, I) form the adducts RhX(PCy₃)₂(N₂) with dinitrogen, the times for N₂-fixation being 4 days, 3 hours and 15 minutes respectively. The three-coordinate complexes form four-coordinate dioxygen adducts RhX(PCy₃)₂(O₂) which have unusually high ν(OO) at about 990 cm^?1. This high frequency is attributed to the four-coordination, which is exceptional for dioxygen complexes. From RhF(PCy₃)₂ carbonyl, ethene, and diphenylacetylene complexes RhX(PCy₃)₂L (X = F, Cl, Br, I, N₃, NCO, NCS; L = CO, C₂H₄, C₂Ph₂) (X = CN, NO₃, acetate; L = CO) have been prepared. The trans-influence of the anionic ligands on the infrared frequencies of the neutral ligands is discussed in terms of the different π-bonding properties of the X- and L-ligands.     

Thermal decomposition of organo-bielemental vanadium compounds Cp2V(ER3) (ER3 - GeEt3, SnEt3, CH2SiMe3 SeGeEt3)

The thermal decompositon of a number of organo-bielemental vanadium compounds with the general formula Cp₂V(ER₃) (ER₃ - GeEt₃, SnEt₃, CH₂SiMe₃, SeGeEt₃) has been investigated in solids and in solution. The main decomposition products of Cp₂V(SnEt₃) are vanadocene and hexaethyldistannane. Et₃GeH, Et₃GeCp, Cp₂V and CpV(C₅H₄GeEt₃) are formed from Cp₂V (GeET₃) decomposition. Isolated CpV(C₅H₄GeEt₃) is characterized by IR and mass spectra. The decomposition of Cp₂V(CH₂SiMe₃) is accompanied by Me₄Si, Cp₂V and CpV-(C₅H₄CH₂SiMe₃) formation, the latter is identified from the mass spectrum. Triethylgermane, vanadocene, and a diselenide of vanadium are isolated on decomposition of Cp₂V(SeGeEt₃). Based upon the experimental data, mechanisms for the decompositon are proposed.     

Actinide-centered cyclometalation chemistry. An unusually distorted thorium bishydrocarbyl: Thp[η5-(CH3)5C5]2CH2Si(CH3)3]2

The crystal and molecular structure of the complex Th[η⁵-(CH₃)₅C₅]₂[CH₂-Si(CH₃)₃]₂, which undergoes facile intramolecular cyclometalation to the thoracyclobutane Th[η⁵-(CH₃)₅C₅]₂(CH₂)₂Si(CH₃)₂, is reported. While the Th[η⁵-(CH₃)₅C₅]₂ ligation is unexceptional, the Th[CH₂Si(CH₃)₃]₂ fragment is highly unsymmetrical having Th-C (corresponding angle Th-C-Si) 2.51(1) Å (132.0(6)°) and 2.46(1) Å (148.0(7)°). This conformation, which appears to result from severe intramolecular non-bonded contacts, allows a methyl hydrogen atom of one CH₂Si(CH₃)₃ ligand to approach within ca. 2.3 Å of the α-carbon atom of the other CH₂Si(CH₃)₃ ligand.     

Synthese et etude des complexes [C5H4(CH2)3C5H4]Ti(C5H5)2 presentant un pont entre deux ligands cyclopentadienyles

The complex (di-η⁵-C₅H₄CH₂CH₂CH₂C₅H₄)Ti(η¹-C₅H₅)₂ (I) can be obtained unambiguously starting from the corresponding bridged titanocene dichloride. Attempts to synthesize the isomeric compounds (η⁵-C₅H₅)₂ Ti(di-η¹-C₅H₄-CH₂CH₂CH₂C₅H₄) (I′) by the action of a convenient bridged dianion on (C₅H₅)₂ TiCl₂ afford several compounds, one of them is the complex I. The possibility of interconversion of these complexes by a fluctional process is discussed.     

Kinetic parameters and solid state mechanism of the thermal dehydration of trans[CrF(H2O)(aa′)2]K[Cr(CN)6]H2O And trans[CrF(H2O)(aa′)2]K[CrNO(CN)5]H2O (aa′=ethylenediamine or 1,3-diaminopropane)

The solid phase thermal deaquation of trans[CrF(H₂O)(aa′)₂]K[Cr(CN)₆]H₂O and trans[CrF(H₂O)(aa′)₂]K[CrNO(CN)₅]H₂O (aa′=ethylenediamine or 1,3-diaminopropane) has been investigated by means of TG measurements. The kinetic parameters (activation energy, E_a, activation entropy, ΔS^#, and frequency factor, k₀) have been determined by comparison of the isothermal and non-isothermal studies for all the principal g(α) expressions. The values found for the activation energy are low (between 80 and 110 kJ mole^?1, approximately) and permit the assignment of the deaquation-anation mechanism of the S_N1 type, involving square-pyramid activated complex and elimination of water as Frenkel defects.     

Synthesis and reactions of the transition metal substituted tin hydride HSn[Mo(CO)3C5H5]3

Reaction of HMo(CO)₃C₅H₅ and Sn(C₅H₅)₂ produces the tin hydride HSn[Mo(CO)₃C₅H₅]₃ (I). Reaction of I with CCl₄, CHCl₃, or CH₂Cl₂ gives ClSn[Mo(CO)₃C₅H₅]₃ (II). With hydrogen chloride the hydride I reacts to produce the dichloride Cl₂Sn[Mo(CO)₃C₅H₅]₂. The first step in this reaction is cleavage of the SnH bond to produce the chloride II. The hydride I reacts with acetic acid to produce the diacetate (CH₃COO)₂Sn[Mo(CO)₃C₅H₅]₂.     

Vibrational study of the unusual phase sequence in Tl3Cr(SO4)3: A compound containing [Cr(SO43−3]∞ columns

The polarized Raman spectra of small single crystals of Tl₃Cr(SO₄)₃ have been recorded using the Raman microprobe technique in the temperature range 295–660 K. The behavior of the external modes is analyzed on polycrystalline samples with conventional Raman spectrometer from 100 K to the decompositon temperature 660 K. Analysis of the spectra, in connection with dielectric measurements and X-ray data show that Tl₃Cr(SO₄)₃ undergoes the following space group phase sequence

$\text{P2}{}_1\text{c}\text{→}\text{340}\text{K}\text{R}\text{3}\text{→}\text{450}\text{K}\text{R3c}\text{→}\text{630}\text{K}\text{R}\text{3}\text{c}$

in accordance with the point group relationship

$\text{2}\text{m}\text{→}\text{3}\text{→3m→}\text{3}\text{m}$

     

Preparation and structure of fluorite-type (Sr,Y)Cl2.05

Anion excess colorless fluorite-type strontium-yttrium chloride has been prepared. Single crystals of the SrY compound exhibit a primitive cubic lattice with a = 6.967(1)Å. Two mutually exclusive structural models for solutions, neither of which is exact, are discussed. The first is a vacancy model in which the extra charge which results from substitution of Y³⁺ for Sr²⁺ is balanced by the simultaneous removal of a Sr²⁺Cl^? ion pair. This model requires individual ion sites to be partially occupied and nonequivalent and is strongly suggestive of vacancy ordering. Refinement in space group P1, with sites refined independenty, led to R = 0.1096. The second model describes the structure in terms of a Willis cluster of defects and includes both anion vacancies and interstitial anions. Full-matrix least squares refinement in space group Fm3m, with positions analogous to those in UO_2.12 and (Ca,Y)F_2.10, converged at R = 0.0633 for the 114 face-centered parent structure reflections whose |F|;² > σ(F²). This second model is discussed in relation to a probable true solution which involves longrange order.     

The crystal structure of hydrogen cerium(III) sulfate hydrate, [H3O][Ce(SO4)2] · H2O

[H₃O][Ce(SO₄)₂] · H₂O crystallizes in the monoclinic system with unit-cell dimensions (from single-crystal data) a = 9.359(4), b = 9.926(4), c = 8.444(3) Å, β = 96.53(9)° and space group P2₁/n, z = 4. The structure was solved by conventional heavy-atom methods using 1787 counter-measured reflections (MoKα radiation), and refined using full-matrix least-squares techniques to an R of 0.0465 (ωR = 0.0413). The structure consists of cerium(III) ions in irregular nine-coordination to oxygen atoms from two bidentate sulfate ions, four monodentate sulfate oxygen atoms, and one water molecule. The oxonium ions are present as isolated ions in the structure and take par in the hydrogen bonding network. The Ce-O bond lengths range from 2.454(7) to 2.626(6) Å.     

Synthesis and crystal chemistry of NH3(MoO3)3

NH₃(MoO₃)₃ crystallizes with hexagonal symmetry, space group $\text{P6}{}_3\text{m}$, lattice constants a = 10.568 Å, c = 3.726 Å, and Z = 2. The crystal structure has been determined by Patterson synthesis and refined assuming isotropic temperature factors to a final conventional R value of 0.085. The structure shows a three-dimensional arrangement built up of double chains of distorted MoO₆ octahedra, parallel to the [001] direction. The octahedral double chains are linked among each other through common oxygen atoms. In addition to the shared oxygen atoms, each molybdenum is coordinated to one terminal oxygen. MoO distances range from 1.645 to 2.378 Å and OMoO angles from 74.3 to 114.3°. These results are consistent with the fact that molybdenum in high-valence states shows octahedral coordination with terminal oxygens.     

Cyclic transport of Fe3+ As H[FeCl4] and H[FeBr4] through a dibutyl ether-benzene membrane

Cyclic transport of Fe³⁺ as H[FeX₄], where X is Cl or Br, across solvent-type liquid membranes has been demonstrated. H[FeCl₄] was transported from HCl into HBr across a dibutyl ether—benzene mixture. In HBr the transported species reacted to H[FeBr₄], which moved out to the HCl side against the concentration gradient of Fe³⁺. On the HCl side it was reconverted into H[FeCl₄]. This continued till equilibrium was achieved. Likewise, Fe³⁺, present as H[FeBr₄] in HBr, migrated from HBr into HCl and then back to HBr across the same membrane.     

Sublimation enthalpies of the complexes W(CO)6-x(NCCH3)x (x=1,2,3) and Mo(CO)6-x(NCCH3x(x=1,3)

Vapour pressure measurements have been carried out on the complexes W(CO)_it6-x (NCCH₃x(x=1,2,3) and Mo(CO)_it6-x(NCCH₃x(x=1,3) employing the Knudsen effusion technique. The following enthalpies of sublimation, ΔH²⁹⁸_sub(kJ mole^?1), have been determined from vapour pressure data: W(CO)₅(NCCH₃)=98.1±2.0; W(CO) ₄ (NCCH₃)₂=131.0±6.0; W(CO)₃(NCCH₃₃=103.4±6.0; Mo(CO)₅(NCCH₃)=105.8± 5.6; and Mo(CO)₃(NCCH₃)₃=111.3±3.0.     

He(I) and He(II) photoelectron spectra of 1-aza-1,3-butadiene-tricarbonyliron complexes: [Fe(CO)3(R1NCHCHCHR2)]

He(I) and He(II) photoelectron spectra are reported for the 1-aza-1,3-butadienes (R¹NCHCHCHR² denoted by R¹,R²-ABD) t-Bu,Me-ABD and i-Pr,Ph-ABD and their tricarbonyliron complexes [Fe(CO)₃(R¹,R²-ABD)]. Assignments of ionizations from the iron d and ligand orbitals have been made with the aid of He(I)/He(II) intensity ratios and some semi-empirical molecular orbital calculations on the model ligand Me,H-ABD (MNDO) and on the model complex [Fe(CO)₃(H,H-ABD)] (CNDO/S).A remarkable feature is the lowering of the ionization energy from the Fe d_xz/yz² orbital with respect to the other d orbitals (d_xy/d_x²–y²/d_z²)⁶ by about 0.9 eV, an effect which has not been found for the related [Fe(CO)₃(1,3-butadiene)] complexes. The involvement of the nitrogen lone pair in the bonding between the R¹,R²-ABD and Fe(CO)₃ moieties is discussed.