The crystal structures and magnetic properties of Ba2LaRuO6 and Ca2LaRuO6

Profile analysis of high-resolution, powder neutron-diffraction data was used to refine the previously reported structures of the ordered, distorted perovskites Ba₂LaRuO₆ and Ca₂LaRuO₆. Low-temperature neutron diffraction experiments showed that, at 2K, the former is a Type IIIa antiferromagnet while the latter is Type I. Both compounds have an ordered magnetic moment of $\text{μ}{}_{\mathrm{<mtext>Ru</mtext>}}\text{? 1.95μ}{}_{\mathrm{<mtext>B</mtext>}}$ per Ru⁵⁺ ion. The Néel temperature of Ba₂LaRuO₆ was determined to be 29.5K, and the covalent mixing between the ruthenium and nearest-neighbor anions is described by A²_π = 8.2 ± 1% for Ba₂LaRuO₆ and 8.6 ± 1% for Ca₂LaRuO₆. The ionic radius of a Ru⁵⁺ ion is 0.56 Å. These data are consistently interpreted within the framework of a strongly correlated, half-filled π1 band. Extension of this interpretation to the magnetic data for the perovskites CaRuO₃ and SrRuO₃ leads to a fundamental theoretical prediction.     

Syntheses of some mixed AuOs and PtOs clusters and the X-ray structure of [Os4H2(CO)12(AuPPh3)2]

Some reactions of [Os₄H₃(CO)₁₂AuPR₃] (R = Et, Ph) resulting in the formation of [Os₄H₂(CO)₁₂(AuPR₃)₂] are presented. A single-crystal X-ray structure of [Os₄H₂(CO)₁₂(AuPPh₃)₂] is reported and reveals a novel Ph₃PAuAuPPh₃ unit asymmetrically bridging one edge of an Os₄ tetrahedron, the first example of a mixed gold-metal carbonyl cluster with an AuAu bond.     

The preparation and X-ray crystal structure of W3(μCN)3(NO)3(CO)9

The nitrosation of Na[W(CO)₅CN] using amyl nitrite and sulphuric acid in a two phase water— diethyl ether system gives the trinuclear compound W₃(μCN)₃(NO)₃(CO)₉. A single crystal X-ray diffraction study showed that the compound contains a nine-membered ring of three tungsten atoms and three bridging cyanide groups. The terminal carbonyl and nitrosyl ligands were not distinguishable.     

Synthesis and structural characterization of the electron rich complexes Co(η-C5Me5)(R2PCH2CH2PR2) (R = Me,Ph); photoelectron spectroscopic studies of some pentamethylcyclopentadienylphosphinecobalt complexes

The compounds Co(η-C₅Me₅)(R₂PCH₂CH₂PR₂), (R = Me, Ph) have been prepared and characterized. X-Ray diffraction studies of Co(η-C₅Me₅)-(Me₂PCH₂CH₂PMe₂) show the two phosphorus atoms and the ring centroid to have a trigonal coordination around the cobalt. Photoelectron spectral studies show Co(η⁵-C₅Me₅)(R₂PCH₂CH₂PR₂) to have rather low first ionization energies of around 5.1 eV, indicating that the metal centre has a very electron rich nature.     

Some studies on the solid solutions in the systems Sr2Nb2O7Eu2Nb2O7 and Sr2Ta2O7Eu2Ta2O7

Preparation of new solid solutions containing divalent europium have been tried in the systems Eu₂Nb₂O₇Sr₂Nb₂O₇ and Eu₂Ta₂O₇Sr₂Ta₂O₇. These solid solutions described as Eu_2xSr_2(1?x)M₂O₇ (M = Nb and Ta) exist in a pure orthorhombic phase in a limited region of x from 0 to about 0.5. The compounds with compositions close to Eu₂M₂O₇ exist but techniques have not been found to prepare them in pure form.     

Synthesis of π-(arene)metallocarboranes containing iron and ruthenium. Crystal structure of 3,1,2-(η6-1,3,5-(CH3)3C6H3)FeC2B9H11

The reaction of bis(arene)iron(II) salts (arene = mesitylene or hexamethylbenzene) or benzenedichlororuthenium(II) dimer with Tl[3,1,2-TlC₂B₉H₁₁] in THF produces neutral, air-stable π-(arene)(Fe, Ru)C₂B₉H₁₁ complexes in low or moderate yields. The metallocarboranes are formal analogues of [π-(arene)Fe, Ru)ⁿ⁺(C₅H₅)] species, and a single crystal X-ray structure of the title compound has established the closo sandwich geometry expected for the molecule on the basis of electron counting rules. The carborane cage was found to be disordered in the crystal but the essential features of the molecular geometry were not obscured. The mesitylene is symmetrically bound to the iron, and the Fe-arene (centroid) distance of 1.60 Å is similar to that found in the previously-characterized [(CH₃)₆C₆]Fe^I(C₅H₅) complex, despite the difference in the metal electronic configurations (d⁶ vs d⁷) and the change from the B₉C₂H₁₁^2? cage to C₅H₅^?. Crystals of 3,1,2-(η⁶-1,3,5-(CH₃)₃C₆H₃)FeC₂B₉H₁₁ are orthorhombic, space group Pn2₁a, with a = 12.638(4), b = 12.432(4), c = 9.686(3) Å.     

Die kristall- und molekülstruktur von Fe3Te2(CO)9

The crystal and molecular structure of Fe₃Te₂(CO)₉ has been determined by X-ray diffraction analysis. The compound crystallizes in the triclinic space group P$\text{1}$ with a 952.5(4), b 1314.3(8), c 694.7(2) pm, α 95.27(4), β 112.78(3), γ 81.44(4)° and Z = 2 (R = 0.036, using 2079 reflections).     

Infrared spectra of Ag2BrNO3 and Ag2ClNO3

The infrared spectra of Ag₂BrNO₃ and Ag₂ClNO₃ are reported. Vibration assignments are proposed on the basis of the group theoretical analysis and D_2h symmetry. Factor group, site and TO-LO splittings are observed. The internal and external mode frequencies are correlated with those of AgNO₃ and KNO₃(II).     

Platinum-195 NMR studies of Pt(LL)2 (LL = −S2PR2, −S2P(OR)2, −S2CNR2) and their derivatives with phosphorus containing ligands

Platinum-195 NMR spectra have been recorded for CH₂Cl₂ solutions of a range of Pt(LL)₂ (LL = ^?S₂PR₂, ^?S₂P(OR)₂, ^?S₂CNR₂) and their derivatives with phosphorus containing ligands. Platinum chemical shifts cover a range of almost 2000 ppm.     

Direct synthesis and NMR spectra of [(C6H5)2PCH2]2CuB5H8: Comments on the solution structure of 2,3-μ-metallopentaboranes

The species [(C₆H₅)₂PCH₂]₂CuB₅H₈ has been prepared directly from [(C₆H₅)₂PCH₂]₂CuI and K[B₅H₈]. NMR spectra unequivocally indicate that the species has a static structure in solution and an argument is presented that all 2,3-,μ-metallopentaboranes have similarly static solution structures.     

The molecular structure of benzoylmethylidynetricobalt nonacarbonyl,C6H5C(O)CCo3(CO)9

The molecular structure of benzoylmethylidynetricobalt nonacarbonyl, C₆H₅C(O)CCo₃(CO)₉, has been determined by single crystal X-ray crystallography. The sample crystallized from heptane forms as monoclinic prisms of spae group P2₁/c, with a = 8.836(2), b = 14.097(10), c = 16.514(3), β = 103.37(6) and z = 2. The final R value was 0.053. The structure is regular and normal but does not aid in explaining the interesting properties of this cluster.     

35Cl NQR in N3P3Cl4Ph2 and N3P3Cl4(NMe2)2

³⁵Cl NQR has been investigated in two cyclotriphosphazene derivatives N₃P₃Cl₄Ph₂ and N₃P₃Cl₄(NMe₂)₂. The observed frequencies are assigned to the various chlorines and the temperature variation of the NQR frequencies studied in the range from 77 K to 300 K. The results are analysed using the Bayer-Kushida-Brown approach. Torsional (librational) frequencies are found to fall in the range 10–25 cm^?1 and are found to be only slightly temperature dependent.     

The influence of the steric properties of the ligands PR2Ph and L on the formation and properties of the complexes Mo(η6-PhPR2)(L)(PPh2CH2CH2PPh2), R = Et,L = PPhEt2 and R = Ph,L = PPh3, PR′3, CO,CNR, N2, H2

The reduction of MoCl₄(DPPE) (DPPE = PPh₂CH₂CH₂PPh₂) with Mg or Na/Hg in the presence of 2 PPhR₂ under Ar results in the formation of the new complexes Mo(η⁶-PhPR₂)(PPhR₂)(DPPE) when R is Ph (Ia) or Et(II). No η⁶-PhPR₂ complex is obtained when R is Me because this small ligand forms strong MoP σ-bonds; nor is one obtained for R = Cy because of too much steric crowding. The limits for η⁶-complexation can be quantified in terms of cone angle sums.Complex Ia is very similar to Mo(η⁶-PhPMePh)(PMePh₂)₃ (IIIa) in that both react at similar rates with a variety of small ligands L = PMePh₂, PMe₂Ph, PMe₃, P(OMe)₃, N₂, CO, CNBu^t and H₂ via dissociation of a labile σ-bonded ligand. Several other less crowded η⁶-arylphosphinemolybdenum complexes including II do not have labile ligands at 25°C. The new complexes Mo(η⁶-PhPPh₂)(L)(DPPE) have been characterized by ³¹P and ¹H NMR, IR and gas uptake measurements, Ia has a higher affinity for H₂ than IIIa possibly because Mo(η⁶-PhPPh₂)(H)₂(DPPE) adopts a non-fluxional trans-configuration. The ³¹P chemical shift of the σ-bonded ligand in 8 derivatives of Ia and 12 of IIIa correlate with the sum of the cone angles of the three σ-bonded ligands in each complex.     

The preparation and X-ray structure of (disulphurdinitrido)bis(triphenylphosphine) platinum(II)—tetrachloroform solvate,Pt(S2N2)(PPh3)2·4CHCl3

Reaction of Pt(PPh₃)₃ with S₄N₄H₄ gives cis-Pt(S₂N₂)(PPh₃)₂ (1) in 45% yield. 1 was characterised be IR     

Vibrational and luminescence spectra of a new binuclear uranyl complex [(C2H5)4N]2[UO2F(NO3)2]2

The preparation, vibrational and luminescence spectra of the title compound are described. The complex has bidentate nitrate groups and bridging fluoride ions. The spectra are assigned in detail and interpreted as showing couplings between the uranyl antisymmetric stretching modes and between the nitrate modes within the dimer, the coupling energy being 17 cm^? in the former case. There is no clear evidence for electronic coupling involving the uranyl groups.     

The preparation of cis- and trans-[PtH(C6Cl5)(PEt3)2 and a study of the “hydride-donor capacity” of the complexes trans- [PtH(C6X5(PEt3)2] (X = F and Cl)

The preparations of cis- and trans-[PtH(C₆Cl₅)(PEt₃)₂] by thermal decomposition of cis- and trans-[Pt(OCHO)(C₆Cl₅)(PEt₃)₂], respectively, are reported. Also described are cis- and trans-[Pt(SnCl₃)(C₆Cl₅)(PEt₃)₂], obtained by treating SnCl₂ with cis- and trans-[PtCl(C₆,Cl₅)(PEt₃)₂], respectively. It is shown that while trans- [PtH(C₆Cl₅)(PEt₃)₂] does not form hydride-bridged complexes in the presence of trans-(PtH(MeOH)(PEt₃)₂]⁺, the corresponding complex trans-[PtH(C₆)(PEt₃)₂] reacts with the same solvento complex, in methanol, giving labile [(PEt₃)₂HPt(-μH)Pt(C₆F₅)(PEt₃)₂]⁺.     

WCl6/LiAlH4 Promoted transformation of imines into secondary and tertiary amines

The reaction of WCl₆/LiAlH₄ with imines, R′NCHR, gave tertiary amines, R′N(CH₂R)₂, and secondary amines, R′NHCHRCH₂R. Isotope labeling experiments revealed that the reaction involved two types of azatungstenacyclobutanes, $\text{WNR′CHRC}$HR and $\text{WCHRNR′C}$HR, produced from the reaction of an alkylidene tungsten intermediate with the imine CN double bond. Formation of these metallacyclobutanes is highly dependent on the solvent used.     

Conformational analysis in diastereoisomer equilibria of square-pyramidal [C5H5(CO)2Mo pyridine-2-imine]PF6 complexes

Synthesis and characterization of sonic new square-pyramidal pyridine-2-imine complexes [C₅,H₅,(CO)₂,MoNC₅,H₄,CX=NCH(R₁)(R₂)]PF₆ with X = CH₃, C₆H₅ and chiral amine, 1-phenyl-isobutylamine and amino acid methyl ester H₂NCH(COOCH₃)(R) with (R) = (CH₂C₆H₅) and (C₂H₅) have been reported. In combination with Mo chirality (R) and (S), mixtures of two diastereoisomeric pairs of enantiomers with racemic amine and amino acids were obtained which were separated by fractional cystallization. The diastereoisomers differ in the chemical shift of most of their ¹H NMR signals and interconvert on heating in acetone-d₆ at 80°C for 80 hr and 40°C for 200 hr. On the basis of three conformational determining effects (i) C-H or C-alkyl of the asymmetric centre eclipses the ligand plane, (ii) MC₅H₅/C₆H₅ attraction and (iii) MC₅H₅/alkyl repulsion in order of decreasing significance, the chemical shifts of the C₅H₅ signals, their differences as well as the diastereoisomer ratio at equilibrium for all the complexes has been rationalised.     

The synthesis and decarbonylation of (η5-C5H5)Mo(Co)2(COCH3)E(C6H5)3, where E is arsenic or antimony

The synthesis of the title compounds by reaction of (η⁵-C₅H₅)Mo(CO)₃CH₃ with excess As(C₆H₅)₃ or Sb(C₆H₅)₃ in CH₃CN is described. Thermal decarbonylation results in the preferential ejection of As(C₆H₅)₃ or Sb(C₆H₅)₃ from the new acetyl complexes, which accounts for the failure of previous attempts to synthesise the acetyl complexes. Photolytic decarbonylations lead to new-alkyl complexes (η⁵-C₅H₅)Mo(CO)₂(CH₃)E(C₆H₅)₃. IR and NMR data for the new complexes are tabulated.