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).     

Infrared spectroscopic properties of water molecules dissolved in some oxygen bases

The infrared spectra in the OH-stretching and HOH-bending regions of H₂O, and in the OH-stretching region of HDO dissolved in a number of ketones and ethers have been recorded. The number of component bands and their wavenumbers, halfwidths and intensities, as well as the total OH-stretching intensity in each solvent, have been interpreted in terms of a model for the types of hydrogen bonded solvent:water complexes formed in these systems.The effect of temperature on the spectra of H₂O in some of the ketones has been rationalized on the basis of the equilibrium existing between the different hydrogen bonded species present in solution.     

Synthesis of 3-[5-anilino-(2,3-d)-dioxole-1,3]-1-oxo-1,3-dihydro-2-benzofurane

A microscale synthesis (500 mg) of the product 3-[5-anilino-(2,3-d)-dioxole-1,3]-1-oxo-1, 3-dihydro-2-benzofurane (COR.01.126) is described. This method, which requires only four steps, is principally available for the ¹⁴C-labeled synthesis with labeled phthalic anhydride as starting material.     

Quantitative Absorption spectra via photoacoustic phase angle spectroscopy (ΦAS)

By measuring the phase angle of the photoacoustic signal it is possible to calculate the quantitative absorption spectrum of a condensed phase sample, if in addition only the sample thermal diffusivity is known. The technique also extends the upper limit of absorptivity which may be usefully studied photoacoustically by a factor of 10.     

Ca7Au3 and Ca5Au4, two structures closely related to the Th7Fe3 and Pu5Rh4 types

Two new intermetallic compounds have been synthetized and structurally studied by single crystal diffractometric data: Ca₇Au₃ (oP80, space groupPbca,a = 20.742(8), b = 18.036(8), c = 6.665(2) A?,Z = 8, R = 0.051) and Ca₅Au₄ (mP18, space groupP2₁/c, a = 8.028(3), b = 8.019(6), c = 7.727(3) A?, β = 109.16(6)°,Z = 2, R = 0.104). Both atomic arrangements, which represent new structural types, are based on Au-centered Ca trigonal prisms and are geometrically related to the Th₇Fe₃ and Pu₅Rh₄ structures.     

Phase transition in V5O9

Electrical resistivity, magnetic susceptibility, and heat capacity of V₅O₉ have been measured through its phase transition temperature (T_t) around 129 K. The associated changes in enthalpy and entropy were found to be 2095 J/mole and 19.24 J/mole · deg., respectively. A qualitative thermodynamic analysis has been attempted to correlate the crystal symmetry, electrical, magnetic, and heat capacity behavior at T_t. The metal-semiconductor transition appears as a consequence of the crystallographic order-disorder process, since the electrical and magnetic contributions to configurational entropy change are relatively small.     

Polysilane derivatives of the transition metals II. The crystal and molecular structure of [tris(trimethylsilyl)silyl]pentacarbonylmanganese, (Me3Si)3SiMn(CO)5

The crystal and molecular structures of [tris(trimethylsilyl)silyl]pentacarbonylmanganese, (Me₃Si)₃SiMn(CO)₅, have been determined from three-dimensional X-ray data obtained by counter methods. The compound crystallizes in space group P$\text{1}$ of the triclinic system, with two molecules in a unit cell of dimensions: a = 9.002(2), b = 9.655(2), c = 15.639(3) Å, α = 83.66(1), β = 105.65(1), γ = 114.61(1)°.The observed and calculated densities are 1.20 (±0.03) and 1.23 g-cm^?3 respectively. Full-matrix least-squares refinement of the structure has led to a final value of the conventional R factor of 0.059 for the 818 independent reflections having F² > 3σ(F²).The coordination geometry about the manganese atom is approximately octahedral and, about the silicon atom bonded to the manganese atom, tetrahedral.The relative orientations of carbonyl and trimethylsilyl groups, when viewed down the MnSi bond, appear consistent with minimization of energy due to nonbonded interactions.Two of the equatorial carbonyl groups are displaced out of the equatorial plane towards the silicon ligand by 6°. The SiMn bond is 2.564(6) Å long and has no multiple character.     

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.     

Trivalent phosphorus derivatives of group via : IV. Infrared and pmr studies of the protonation of M(CO)6−n(PA3)n Complexes (M = Mo,W; A = CH3, OCH3; n = 2, 3, 4)

The action of trifluoroacetic acid on the series M(CO)_6?n(PA₃)_n (M = Mo, W; A = CH₃, OCH₃; n = 2, 3, 4) has shown that protonation occurs if n ? 3. For n = 3 the basicity of the ligand PA₃ plays a more important role in the stability of [HM(CO)₃(PA₃)₃]⁺complexes than for n = 4. Infrared and proton NMR give evidence of the stereochemical non-rigidity of the [HM(CO)_6?n(PA₃)_n]⁺ heptacoordinated cation.     

Crystal structure and fast ionic conduction of TIZrF5

TlZrF₅ crystallizes in the monoclinic system with unit cell dimensions a = 8.112(1) Å, b = 7.927(3) Å, c = 7.929(1) Å, β = 123.99(1)° and space group P2₁/c (n^o 14); Z = 4. The structure was solved by conventional Patterson and Fourier methods and refined by full-matrix least-squares techniques to a conventional R of 0.057 (R_ω = 0.063). The structure consists of sheets of (ZrF₅)^? that may be described as edge-shared and corner-shared bicapped trigonal prisms (ZrF₈). The sheets run parallel to the y0z plan and are bonded together by the Tl ions which are surrounded by 12 F^? ions. The ionic conductivity of TlZrF₅ and TlHfF₅ has been investigated by complex impedance measurements and the relationships between structure and fast-ionic conduction are discussed.     

Nonpyridinic derivatives in C-5 of 2-thiohydantoin for spectrophotometric determination of palladium

The reactions between Pd(II) and four nonpyridinic derivatives of 2-thiohydantoin (5-benzal-2-thiohydantoin, 5-(o-hydroxy)benzal-2-thiohydantoin, 5-(m-hydroxy)benzal-2-thiohydantoin, and 5-anisal-2-thiohydantoin) have been considered. The influence of the different experimental parameters on the formation of the complexes was studied, and the optimum conditions for the determination of palladium were established. The anisal derivative was selected among these four reagents and the spectrophotometric determination of palladium described in detail. The precision of the procedure, expressed in terms of relative standard deviation was 0.9%, and numerous ions that usually interfere in palladium determination, such as Os(VIII), Rh(III), and Ru(IV) (of the platinum group) and Pb(II), Cd(II), Ni(II), Co(II), Zn(II), and others of the transition series, were tolerated.     

Photoelectronic properties of Cu3PS4 and Cu3PS3Se single crystals

Single crystals of Cu₃PS₄ and Cu₃PS₃Se grown by chemical vapor transport were shown to be diamagnetic p-type semiconductors. Electrical measurements showed room temperature resistivities ranging from 1 to 5 ohm-cm and carrier concentrations of 10¹⁷ cm^?3. Both materials were shown to be active as cathodes for the photoelectrolysis of water. Spectral response measurements show that substitution of selenium for sulfur lowers the optical band gap from 2.38(5) eV for Cu₃PS₄ to 2.06(4) eV for Cu₃PS₃Se.     

Ionic conductivity of Li2MgSn3O8 ramsdellite

The ionic conductivity of polycrystalline pellets of Li₂MgSn₃O₈ with ramsdellite-type structure was measured by complex impedance technique. The conductivity is 1.2 × 10^?8 (Ω cm)^?1 at 300°C and 2.3 × 10^?4 (Ω cm)^?1 at 450°C. The results are discussed in relation to structural properties.     

Defect structures in the brannerite-type vanadates: VI. Preparation and study of Co1−x∅xV2−2xMo2xO6 and phase diagram of the ternary CoO-V2O5-MoO3 system

The phase diagram of the ternary CoO-V₂O₅-MoO₃ system and in particular its T-CoV₂O₆-MoO₃ slice have been determined with DTA and X-ray phase analysis. CoV₂O₆ crystallizes in two modifications: a low-temperature γ-form of unknown structure and a high-temperature α-form of brannerite-type structure. The transition temperature is 660-665°C. The γ ? α transformations are very slow and the α-polymorph may be easily frozen. On doping with MoO₃, a solid solution is formed that is described by the formula Co_1?x?_xV_2?2xMo_2xO₆. Above x = 0.02 the α-type structure is stabilized. The x_max equals 0.22 at the eutectic temperature of 620°C and 0.20 at room temperature. Other features of the phase diagram, including its division into the natural subdiagrams and three ternary eutectics, are described in detail. X-Ray data are listed for α-CoV₂O₆ and for the solid solution having x = 0.20. On doping with MoO₃ the monoclinic lattice dilates primarily in the direction of the b-axis.     

Rare earth transition metal sulfides,LnMS3

Ternary rare earth transition metal sulfides LnMS₃ with Ln = La, Nd, and Gd, and M = V and Cr; as well as Ln = La and M = Mn, Fe, Co, and Ni have been prepared and characterized. The vanadium and chromium sulfides crystallize in a monoclinic layer structure isotypic with LaCrS₃, while the other LnMS₃ sulfides crystallize in a hexagonal structure. Chemical shifts of the metal K-absorption edge and XPS binding energies of core levels indicate that the transition metal is trivalent in the V and Cr sulfides, while it is divalent in the Mn, Fe, Co, and Ni sulfides. Electrical and magnetic properties of the sulfides are discussed in terms of their structures and the electronic configurations of the transition metal ions.     

Synthesis of robustin and related 4-hydroxy-3-phenyl coumarins and isoflavones

Robustin (31a) occurring in the roots of Derris robusta has been synthesised from mono-O-methylphloroglucinol (20) as follows. Hoesch condensation with homopiperonitrile (21) gave 2,4-dihydroxy-6-methoxyphenyl 3,4-methylenedioxybenzyl ketone (22) which on reaction with 2-hydroxy-2-methyl-3-butene in the presence of borontrifluoride-etherate afforded 5-C-(24) and 3-C-(23) prenyl derivatives. These on cyclodehydrogenation with DDQ followed by coumarin condensation with ethyl chloroformate yielded robustin (31a) and isorobustin (32) respectively. Model experiments with nuclear prenylation of 2,4-dihydroxy-6-methoxy-phenyl benzyl ketone (1), followed by oxidative cyclisation and either courmarin or isoflavone condensation have yielded new isopentenylated 4-hydroxy-3-phenylcourarins or isoflavones.     

Heat capacity of pure and doped V2O3 single crystals

Heat capacities have been measured for single crystals of V₂O₃, either pure or doped with 1 and 1.4 mole% Cr₂O₃ and Al₂O₃ over the temperature range 100–700°K. V₂O₃ undergoes a fairly sharp transition at low temperatures (～170°K) but fails to exhibit any thermal anomaly above 300°K. The thermal behavior of (M_xV_1?x)₂O₃, M = Cr, Al, is manifested by two transitions: one at low temperatures, 170–180°K for x = 0.01 and 180–190°K for x = 0.014, and the other at high temperatures. For x = 0.01, the high-temperature (HT) anomaly extended over the range 325–345°K (Cr-doped V₂O₃) and 345–365°K (Al-doped V₂O₃), respectively. The corresponding ranges for x = 0.014 were found to be 260–280°K and 270–290°K, respectively. Further, the HT anomaly was characterized by a large hysteresis (～50°K). The values of lattice heat capacity of pure and doped V₂O₃ were, however, found to be almost the same and could be empirically represented by the Debye (D)?Einstein (E) function $\text{D}\text{(}\text{580}\text{T}\text{) + 4}\text{E}\text{(}\text{θ}\text{T}\text{)}$ with θ values 430°K (T = 100–230°K) and 465°K (T > 230°K), respectively. Further, the enthalpy change ΔH associated with the HT anomaly in doped V₂O₃ (80 ≤ ΔH ≤ 510 J/mole) was 5–10 times smaller than the ΔH corresponding to the lower-temperature transition. The results cited here appear incompatible with the Mott transition model that has been invoked to explain the HT anomaly.     

The unusual iron complex with a trimethylenemethane type ligand, (η5-cyclopentadienyldicarbonylmanganese)- (phenylmethylene)carbomethaneiron tricarbonyl [Cp(CO)2 MnC(CO)CHPh]Fe(CO)3

The binuclear complex with composition [Cp(CO)₂ MnC(CO)CHPh]Fe(CO)₃ is obtained by interaction of CpMn(CCHPh)(CO)₂ with Fe₂C0)₉. An X-ray study of this complex has shown that besides three carbonyl groups the iron atom is covalently bonded to four atoms, viz. the carbon of a phenylmethylene group, the carbon of a bridging CO group, the manganese atom and the central carbon of the organomanganese ligand lying just above iron. It seems to be the first example of a heteroatomic analogue of trimethylenemethane complexes.     

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.