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.     

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.     

Dinuclear formamidino and triazenido compounds [{2,6-(Me2NCH2)2C6H3} (p-tolylNYNR)PtHgBrCl] (Y  CH,N) containing a platinum-to-mercury donor bond

Complexes [{2,6-(Me₂NCH₂)₂C₆H₃} (p-tolylNYNR)PtHgBrCl] (Y  CH, N; R  Me, Et, i-Pr) have been prepared by the reaction of [{2,6-(Me₂NCH₂)₂C₆H₃}-PtBr] with [Hg(p-tolylNYNR)Cl]. Similar complexes were obtained, although in lower yields, from exchange reactions of [{2,6-(Me₂NCH₂)₂C₆H₃} (RCO₂)-PtHg(O₂CR)Br] with p-tolylNNN(H)-p-tolyl and p-tolylNC(H)N(H)Et.The proposed structure for these heterodinuclear compounds involves a Pt-to-Hg donor bond which is bridged by a triazenido (Y  N) or a formamidino (Y  CH) group, the five-membered ring thus formed acting as a stabilizing factor. The absence of a subsequent electron transfer reaction is ascribed to the constraints of the terdentate 2,6-(Me₂NCH₂)₂C₆H₃ ligand, which fixes the N-donor atoms in mutual trans-positions.The use of p-tolylNYNR, where R is an alkyl group, results in the formation of two isomers of [{2,6-(Me₂NCH₂)₂C₆H₃} (p-tolylNYNR)PtHgBrCl] with p-tolyl-N and alkyl-N sites bonded either to Pt or Hg. The relative abundance of these isomers varies systematically with the nature of the group R. It is suggested that the ratio is determined during the formation of the complexes and that both steric and electronic factors are important.     

Phases and phase transitions of compounds (CnH2n+1NH3)2MnCl4 with n = 1, 2, 3

Phases and structural phase transitions of the compounds (CH₃NH₃)₂MnCl₄, (C₂H₅NH₃)₂MnCl₄ and (C₃H₇NH₃)₂MnCl₄ have been studied by means of thermoanalytical methods (DSC) and X-ray single crystal and powder diffraction data in the temperature range of 85–480°K at normal pressure. All phases show perovskite-like layer structures. The high temperature phases (α phase) correspond to the K₂NiF₄ type and may be regarded as the aristotype of each polymorphic compound. All transitions are reversible. Transition patterns are:

Based on the DSC peak-shape analysis and diffraction data a model of a tilting system of the MnCl₆-octahedra layer is introduced in order to understand essential features of structures of different phases and their transition behavior. Single crystal film data of (C₃H₇NH₃)₂MnCl₄ phases reveal some disorder phenomena. The ε phase exhibits a superstructure along [010] with a triplication of the shortest axis corresponding to the δ phase. The γ phase of this compound shows strong satellite reflections, due to a transverse distortion wave along the [100] lattice direction.     

The chemiluminescent reaction between H3B-N(CH3)3 and O(3P) atoms; relative rates

At ambient temperatures, oxygen atoms attack borane-trimethylamine initially at the H₃B moiety to displace the amine. The subsequent attack on BH₂and BH generates highly excited BO (A²Π,v?11) which is the source of chemiluminescence. The rates of destruction of H₃BNMe₃ and H₃BNEt₃ are approximately two orders of magnitude faster than the comparable rate for H₃BCO.     

Further studies on organonickel compounds: the synthesis of some new alkyl-, acyl- and cyclopentadienyl-derivatives and the crystal structure of trans-[Ni(CH2SiMe3)2(PMe3)2]

The complex [NiCl₂(PMe₃)₂] reacts with one equivalent of mg(CH₂CMe₃)Cl to yield the monoalkyl derivative trans-[Ni(CH₂CMe₃)Cl(PMe₃)₂], which can be carbonylated at room temperature and pressure to afford the acyl [Ni(COCH₂CMe₃)Cl(PMe₃)₂]. Other related alkyl and acyl complexes of composition [Ni(R)(NCS)(PMe₃)₂] (R = CH₂CMe₃, COCH₂CMe₃) and [Ni(R)(η-C₅H₅)L] (L = PMe₃, R = CH₂CMe₃, COCH₂CMe₃; L = PPh₃, R = CH₂CMe₂Ph) have been similarly prepared. Dialkyl derivatives [NiR₂(dmpe)] (R = CH₂SiMe₃, CH₂CMe₂Ph; dmpe = 1,2-bis(dimethylphosphine)ethane, Me₂PCH₂ CH₂PMe₂) have been obtained by phosphine replacement of the labile pyridine and NNN′N′-tetramethylethylenediamine ligands in the corresponding [Ni(CH₂SiMe₃)₂(py)₂] and [Ni(CH₂CMe₂Ph)₂(tmen)] complexes. A single-crystal X-ray determination carried out on the previously reported trimethylphosphine derivative [Ni(CH₂SiMe₃)₂(PMe₃)₂] shows the complex belongs to the orthorhombic space group Pbcn, with a = 14.345(4), b = 12.656(3), c = 12.815(3) Å, Z = 4 and R 0.077 for 535 independent observed reflections. The phosphine ligands occupy mutually trans positions P-Ni-P 146.9(3)° in a distorted square-planar arrangement.     

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.     

Solid-state decomposition studies on fluoroperoxo species of transition metals. Part VI. Kinetics of isothermal decomposition of M2Zr2(O2)2F6 · 2 H2O (M = Rb+, or Cs+)

The decomposition of solid fluoroperoxozirconates of alkali metals, M₂Zr₂(O₂)₂F₆ · 2 H₂O (M = Rb⁺, Cs⁺), is carried out in vacuum under isothermal conditions. The stoichiometry of the reaction may be represented by the equation, M₂Zr₂(O₂)₂F₆ · 2 H₂O(S) — M₂Zr₂O₂F₆(s) + O₂(g) + 2 H₂ O(g) (condensed). The fractional decomposition α is determined by measuring the pressure of oxygen evolved during pyrolysis with a McLeod gauge. The α values range from 0.06 to 0.70 for the rubidium and from 0.06 to 0.79 for the caesium species in the temperature ranges 107–202°C and 101–219°C, respectively. The α—time data for both compounds show that the kinetics are deceleratory throughout the course of the decomposition reaction. In both compounds, the initial stages of decomposition are described by a unimolecular decay law, while the later stages obey a contracting volume equation at all temperatures. The activation energies from Arrhenius plots are 14.0 and 10.9 kcal mole^?1 for the rubidium and 12.9 and 11.2 kcal mole^?1 for the caesium compound.     

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.     

Sm2O3Ga2O3 and Gd2O3Ga2O3 phase diagrams

Four definite compounds exist in the Sm₂O₃Ga₂O₃ binary phase diagram, namely: Sm₃GaO₆, Sm₄Ga₂O₉, SmGaO₃, and Sm₃Ga₅O₁₂. The $\text{3}\text{1}$ compound is orthorhombic (space group Pnna - Z.4) with the cell parameters: a = 11.40₀Å, b = 5.51₅Å, c = 9.07Å and belongs to the oxysel family. Sm₃GaO₆ and SmGaO₃ melt incongruently at 1715 and 1565°C; Sm₄Ga₂O₉ and Sm₃Ga₅O₁₂ have a congruent melting point at 1710 and 1655°C. With regard to the Gd₂O₃Ga₂O₃ system three definite compounds have been identified: Gd₃GaO₆, Gd₄Ga₂O₉, and Gd₃Ga₅O₁₂. Only the garnet melts congruently at 1740°C with the following composition: Gd_3.12Ga_4.88O₁₂. Gd₃GaO₆, and Gd₄Ga₂O₉ melt incongruently at 1760 and 1700°C. GdGaO₃ is only obtained by melt overheating which may yield an equilibrium or a metastable phase diagram.     

Massenspektrometrische-, dta- und tg-untersuchungen an eisencarbonylchalkogeniden Fe2(CO)6X2 (X  S,Se) und Fe3(CO)9X′2 (X′  S,Se, Te)

Mass spectra of Fe₃(CO)₉X₂ (X  S, Se, Te) and Fe₂(CO)₆X′₂ (X′  S, Se) are recorded and their fragmentation pattern given. The thermal decarbonylation has been studied using DTA/TG methods in the temperature range 25–600°C. The results are compared with those obtained from mass-spectroscopic studies. X-ray and magnetic measurements have been carried out on the residues obtained in the decarbonylation process.     

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.     

Thermodynamics of Sr(NO3)2 and Cd(NO3)2 in mixed solvents from viscosity data

The viscosities of Sr(NO₃)₂ and Cd(NO₃)₂ have been determined in dioxane, glycol and methyl alcohol+water mixtures at 10, 20 and 30% by weight. The B values have been computed at different temperatures both from the Jones—Dole and Das's equation. From the B values, the effective rigid molar volume, its change with % of organic solvent, temperature and the ion—solvent interaction have been inferred. Activation parameters have also been calculated and the structure breaking effect has been deduced.     

Thermally induced incomplete high-spin (5T2) ⇌ low-spin (1A1) transition in solid bis[2-(2-pyridylamino)-4-(2-pyridyl) thiazolato]iron (II)

The ⁵⁷Fe Mössbauer effect in two samples (A and B) of [Fe(papt)₂] and in its solvates with CHCl₃ and C₆H₆ has been studied between 4.2 and 343 K and clearly indicates a temperature induced high-spin (⁵T₂) ? low-spin (¹A₁) transition in these compounds [paptH = 2-(2-pyridylamino)-4-(2-pyridyl) thiazole]. At 343 K, sample B shows a doublet with ΔE_Q = 2.03 mm s^?1 and δIS = +0.87 mm s^?1, characteristic of a ⁵T₂ ground state. At 257 K, a second doublet, typical for a ¹A₁ ground state, is observed and its intensity increases as the transition progresses but levels off below ～ 100 K. At 4.2 K, 83% of the intensity is due to the ¹A₁ state, and ΔE_Q(¹A₁) = 1.56 mm s^?1 and δ^IS(¹A₁ = +0.32 mm s^?1. In an applied magnetic field, V_zz(¹A₁) < 0 and η ≈ 0.7 have been determined, whereas for the ^sT₂ ground state, V_zz(^sT₂) > 0, η ≈ 0.75, and an internal hyperfine field H_n ≈ ?13 kG have been observed. Similar results have been obtained with the other samples.Debye-Waller factors f5_T2 and f1_A1 were determined from the saturation corrected areas in the Mössbauer spectra, assuming Curie-Weiss dependence of the magnetic susceptibility for the ⁵T₂ and constant υ_cff for the ¹A₁ ground state. The temperature dependence of ?In f1_A1 closely follows the Debye model with Θ1_A1 = 165 K, whereas the same applies to ?ln f5_T2 only above ～ 210 K and Θ5_T2 = 134 K. The nature of the observed transition is discussed and the data presented are shown to be incompatible with a model based on a Boltzmann distribution between the two states.     

Polarized crystal spectra of the mixed metal salt [(CH3)3NH]MnxCu1−xCl3·2H2O

The electronic absorption spectra in two polarizations are reported for crystals of the dichroic salt, TMAMn_xCu_1?xCl₃·2H₂O where TMA represents the trimethylammonium cation, (CH₃)₃NH⁺. Although TMACuCl₃·2H₂O is monoclinic, the mixed metal salts in which x ≥ 0.20 adopt the orthorhombic structure of TMAMnCl₃·2H₂O. The bands observed in the near ir region are adequately explained as d-d transitions of the Cu(II) ion in D_2h symmetry. Other polarized bands which occur in the visible region and are neither Mn(II) nor Cu(II) d-d transitions are discussed.     

Infrared spectra of KNaSO4 and K3Na(SO4)2

The infrared spectra, transmittance and polarized reflectance, of KNaSO₄ and K₃Na(SO₄)₂ are reported. Group theoretical analysis was carried out and a vibrational assignment proposed on basis of C_3v and D_3d symmetries. Factor group and site effects are discussed.     

Thermodynamics of Sr(NO3)2 and Cd(NO3)2 in aquo-organic solvents from conductance data

The ion-solvent interaction of Sr(NO₃)₂ and Cd(NO₃)₂ in 10, 20 and 30 wt.% organic solvent (dioxane, glycol, methyl alcohol)-water mixtures at different temperatures has been studied using electrolytic conductivity data. The dissociation constant of the ion-pair Sr(NO₃)⁺ and Cd(NO₃)⁺ has been calculated along with ΔG⁰_t, ΔG⁰_t(cl) and ΔG⁰_t(ch). The ion pairs interact with the solvents and the interaction is of the order dioxane+water>methyl alcohol+water>glycol+water.     

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 decomposition reactions of [Co(en)n(phen)m]Cl3 complexes

The thermal behaviour of [Co(en)_n(phen)_m]Cl₃ complexes has been studied using thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA) in air, nitrogen and oxygen atmospheres. The effect of the stoichiometry of the complexes and that of the gas atmosphere in the furnace chamber on the thermal decomposition reaction is evidenced and discussed. The following thermal stability order has been found [Co(en)₃]Cl₃ [Co(en)₂(phen)]Cl₃ > [Co(en)(phen)₂]Cl₃ [Co(phen)₃]Cl₃     

Studies on the compounds in the BaFeS system. I. Linear chain antiferromagnetism of Ba2FeS3 and related compounds Ba2CoS3 and Ba2MnS3

Magnetic susceptibilities of Ba₂FeS₃, Ba₂CoS₃, and Ba₂MnS₃ show rounded maxima at 130, 125, and 100 K, respectively, which are due to quasi-one-dimensional antiferromagnetic short-range ordering. Intrachain interactions, $\text{J}\text{k}$, are estimated to be ?20, ?15, and ?12 K, respectively. ⁵⁷Fe Mössbauer spectra of Ba₂FeS₃ and ⁵⁷Fe-doped Ba₂CoS₃ and Ba₂MnS₃ at 4.2 K show long-range antiferromagnetic ordering, due to the interchain interaction. The profile of Mössbauer spectra at 4.2 K is analyzed based on the coexistence of magnetic hyperfine and quadrupole interactions, and magnetic hyperfine fields at 4.2 K are estimated to be 36, 29, and 59 kOe, respectively.