Thermodynamics of carbon dioxide and carbonic acid: (a) the standard enthalpies of solution of Na2CO3(s), NaHCO3(s), and CO2(g) in water at 298.15 K; (b) the standard enthalpies of formation,standard Gibbs energies of formation,and standard entropies of CO2(aq), HCO3−(aq), CO32−(aq), NaHCO3(s), Na2CO3(s), Na2CO3·H2O(s), and Na2CO3·10H2O(s)

Enthalpies of solution of CO₂(g), NaHCO₃(s), and Na₂CO₃(s) in excess NaOH solution were measured at 298.15 K by solution calorimetry. The results were reduced to standard-state processes through use of results from a preceding paper, and standard enthalpies of solution for CO₂(g), NaHCO₃(s), and Na₂CO₃(s) in water at 298.15 K were found to be: ?(4720 ± 40), (4474 ± 30), and ?(6371 ± 30) cal_th mol^?1 respectively. The results of equilibrium studies involving CO₂(g) (solubility and e.m.f. studies) were reviewed and assembled,together with entropies for related solids. Standard values of ΔH_f^o, ΔG_f^o, and S^o at 298.15 K were evaluated for CO₂(aq, non-ionized), HCO₃^?(aq), CO₃^2?(aq), NaHCO₃(s), Na₂CO₃(s), Na₂CO₃·H₂O(s), and Na₂CO₃·10H₂O(s).     

Syntheses and properties of H-1,2,3-triazoles

About twenty new H-1,2,3-triazoles (T) were readily synthesized by nucleophilic attack of sodium azide on activated acetylenes in dimethylformamide. Typical activating groups were COR, COOR, O₂NC₆H₄ PO(OC₂H₅, COT, and (C₆H₅)₃P⁺. Propynyl 4-triazolyl ketone or phenylethynyl 4-triazolyl ketone may be converted to acylic adducts (triazolylketoenamines), biheteroaromatic systems (isoxazolytriazoles, pyrazolytriazoles), as well as to ditriazolyl ketones. Certain T properties were examined in detail. The apparent pK′s for our group of ca 30 triazoles were in the range 4·95?9·45 in ethanol-water (v/v 1/1) at 25°. The Hammett correlation for five 4-aryl-T was log K_a = 0·89σ^? ?9·21 and for seven 4-aryl-5-carbethoxy-T was log K_a = 1·45σ?6·95. The UV spectra of T are similar to those of other heteroaromatic and phenyl compounds: interesting analogies between triazolyl and phenyl, e.g., ”ortho“ crowding effects, appear to be indicated in the spectra of compounds related to biphenyl, stilhene and benzophenone. With regard to structure assignment on the basis of spectra, characteristic features of UV and IR spectra of the H-1,2,3-triazoles are discussed.     

Allylbutyltin halides (CH2CHCH2)SnBu3−nCln (n = 0, 1, 2, 3). Preparation,carbon-13 NMR characterization and allylstannylation ability towards ketones and aldehydes

Mixed allylbutyltin halides (CH₂CHCH₂)SnBu_3-nCl_n (n = 0–3) have been prepared, and characterized by carbon-13 NMR spectroscopy. Their ability to bring about allylstannylation of ketones and aldehydes, to form organostannoxy compounds, Bu_3-nSnCl_nOC(R′)(R″)CH₂CHCH₂, has been shown to increase on increasing the value of n, that is on increasing the acceptor ability of the tin centre.     

Magnetic properties of the layered compounds Ca2Mn3O8 and Cd2Mn3O8

Ca₂Mn₃O₈ and Cd₂Mn₃O₈, which contain Mn⁴⁺ monolayers, have been prepared and characterized. Their magnetic susceptibility and electron paramagnetic resonance (EPR) behavior have been examined in detail. The Mn⁴⁺ moments in both Ca₂Mn₃O₈ and Cd₂Mn₃O₈ order antiferromagnetically near 60 and 10°K, respectively. Although the Néel temperature in Ca₂Mn₃O₈ is in reasonable agreement with molecular-field theory, that in Cd₂Mn₃O₈ is well below its expected value. It is proposed that these results, as well as those in the calcium manganite series CaMnO₃ → Ca₂MnO₄, may reflect the chemical influence of the divalent cation in modifying the MnO covalent mixing.     

Electron spin resonance spectra of α-sulfonyl iminoxy radicals

Syn- andanti-α-sulfonyl iminoxy radicals have been generatedin situ by lead tetra-acetate oxidation of α-oximino sulfones. The ESR spectra of the geometrical isomers have been assigned and the¹⁴N and¹H hyperfine splitting constants are discussed in terms of the proposed structures.     

Über Ordnungs-Unordnungsphänomene bei Sauerstoff perowskiten vom Typ A2+3B2+M5+2O9

Perovskites of the type A²⁺₃B²⁺M⁵⁺₂O₉, where A²⁺ = Ba, Sr; B²⁺ = Mn, Co, Ni, Zn; M⁵⁺ = Nb, Ta, show order-disorder phenomena. At lower temperatures a thermodynamically unstable disordered cubic perovskite is formed ($\text{1}\text{3}$ formula unit—$\text{AB}{}_{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{M}{}_{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}\text{O}{}_3$—in the cell), which transforms irreversibly into a 1: 2 ordered high-temperature form with 3L structure (sequence (c)₃). For A²⁺ = Ba this lattice is hexagonal (space group $\text{P}\text{3}\text{m1}$; one formula unit in the cell); with A²⁺ = Sr a triclinic distortion is observed. For Ba₃CoNb₂O₉ a second transformation into a cubic disordered perovskite takes place at 1500°C. This transition is reversible and of the order-disorder type. The vibrational and diffuse reflectance spectra are discussed.     

Pulsed fourier transform NMR of substituted aryltrimethyltin derivatives : II. (119Sn-13C) coupling constants and 13C chemical shifts of meta- and para-derivatives

Carbon-13 NMR data are reported for thirteen para- and meta-substituted phenyltrimethyltin compounds, RC₆H₄Sn(CH₃)₃, where R = para-N(CH₃)₂, para-OCH₃, para-OC₂H₅, para-CH₃, meta-CH₃, -H, para-F, meta-OCH₃, para-Cl, para-Br, meta-F, meta-Cl and para-Sn(CH₃)₃. In the para-derivatives, correlation coefficients with Hammet σ-constants of greater than ca. 0.9 are obtained with the tin-carbon couplings to methyl, C₁ and C₄ carbons, and with the carbon-13 chemical shifts δ(C(1)). In the meta-derivatives, the couplings |J(Sn-CH₃)|:, |:J(Sn-C(1))|:, |:J(Sn-C(3))|: and |:J(Sn-C(6))|:, and the shifts δ(C(1)) and δ(C(5)) correlate well with Hammett σ. In the para-derivatives, sensitivity to change in substituent falls off C(4) > C(3, 5) > C(1) > C(2, 6) > CH₃ as registered by the δ(C), while in the meta-derivatives δ(C) changes decrease C(3) > C(2), C(4) > C(1) > C(5), C(6) > CH₃. The magnitudes of the tin coupling constants decrease C(1) > CH₃ > C(3, 5) > C(2, 6) > C(4) in the para-derivatives, while in the meta-series the order is C(1) > CH₃ > C(3), C(5) > C(2) > C(6) > C(4). The two sets of one-bond |:J(Sn-CH₃)|: and |:J(Sn-C(1)|: values correspond closely to the 0.25/0.33 ratio of coefficients in the LCAO approach, and are interpreted in terms of s-electron redistributions at the tin atom with change in substituent.     

X-ray and mössbauer studies of tricyclohexyltin(IV) halides. The crystal structures of (cyclo-C6H11)3SnX (X = F,Br and I)

The structures of tricyclohexyltin fluoride (I), bromide (II) and iodide (III) have been determined by X-ray analysis. Compound I crystallizes in the space group P2₁/m with a = 10.422(6), b = 17.238(9), c = 5.769(3) Å, β = 104.6(1)° and Z = 2. Compounds II and III crystallize in the space group Pcmn with a = 10.427(6), b = 16.914(9), c = 11.366(6) Å, Z = 4; and a = 10.400(6), b = 16.900(10), c = 11.400(4) Å, Z = 4, respectively. All three structures consist of discrete tetrahedral (cyclo-C₆H₁₁)₃SnX units.The temperature dependence of the Mössbauer resonance areas has been examined in order to obtain information about the relationship between chemical structure and lattice dynamics.     

13 C 183W-Kopplungen als sonde für metall—carbin-, —carbenund—alkyl-bindungen

Carbon-13 NMR data are reported for trimethyltin derivatives containing ER_n groups where E  C, Si, Ge, Sn, N, O and S including a series of cyclic amines with ring sizes from three to seven. Coupling constant values for the homologous series of fourth group derivatives give goood correlations with the electronegativity of E. The observation of the two-bond, ¦ ²J(¹¹⁹SnE¹³C) ¦ couplings only in the derivatives containing bulky R groups is rationalized by a bimolecular exchange of ER_n groups in the concentrated solutions studied.     

Studies of heterocyclic compounds: III. Synthesis and thermal decompositions of some 2-thiophenemercuric derivatives

2-Thiophenemercuric chloride(I), on reaction with sodium or silver thiocyanate, silver azide, silver acetate, and silver trifluoromethanesulfonate gave the 2-thiocyanate (2), 2-azide (4), 2-acetate (5) and 2-trifluoromethanesulfonate (6), respectively. The thermal decompositions of these compounds, together with that of 2,2'-dithienyl mercury, have been studied. The 2-thiophenemercuric triflate (6) decomposes at room temperature to give 2,2'-dithienylmercury. The 2-azide (4), when treated with either cyclohexene or triphenylphosphine, gave only the 2,2'-dithienylmercury. All the 2-thiophenemercuric salts decompose at about 300°C to give only a black insoluble residue. With the aid of some control experiments and comparison with previous work on phenyl- and p-tolyl-mercuric salts, a mechanism is proposed to account for the results.     

18-Deoxyaldosterone,its chemical and microbial reduction products

Reduction of the diketal 1 with sodium aluminum bis-(methoxyethoxy) hydride afforded the crystalline 18-hydroxycorticosterone diketal (2), an intermediate in the formation of 18-deoxyaldosterone acetate (4b). The hitherto unreported but anticipated metabolites of 4 were prepared as follows: hydrogenations of 4b furnished the fα- and 5β isomers 6 and 5b, and thence the tetra- and hexahydro derivatives 10, 11, 8, 9 and 7, and the 3-deoxy compounds 12 and 13. Anaerobic fermentations of 4b with Clostridium paraputrificum gave the tetrahydro derivative 8b in high yield.     

Oxygen evolution on SrFeO3 electrode

Oxygen evolution reactions on SrFeO₃ were investigated in alkaline and acidic solutions. It was found that the catalytic activity for the oxygen evolution reaction in the alkaline solution is high. The following reaction steps (V)+Fe+2H₂O→(O)+FeOH₂+2H⁺+2e^? in acidic solution and FeOH+OH^?→FeO^?+H₂O in alkaline solution are presumed to be rate-controlling in the anodic evolution of oxygen on SrFeO₃ electrode, where (V) denotes oxygen vacancy on the electrode surface. The reaction mechanism and the catalytic property are discussed in connection to the band structure of the oxide.     

Studies of acenaphthene derivatives—XXVIII : The reaction of 2-diazoacenaphthenone with anils in the presence of boron trifluoride

Reaction of 2-diazoacenaphthenone with anils in the presence of a catalytic amount of boron trifluoride etherate is reported. The diazoketone reacts with benzylidenanilines to afford a mixture of stereoisomers of spiro[acenaphthenone-2′,4-imidazolidine], whose structures correspond to compounds derived from 1:2 adducts of the diazoketone and anils with the elimination of nitrogen. A pathway involving spiro-aziridine intermediates is proposed for their formation. Reaction of the diazoketone with aα-alkylbenzylidenanilines however gives the corresponding acenaphtho[1,2-b]pyrroles, whose structures correspond to compounds arising from 1:1 adducts with the elimination of both nitrogen and water. The reaction of the tautomeric enamine form of the anil with a carbenoid intermediate generated from the diazoketone is suggested for pyrrole formation.     

Pinnatanine and oxypinnatanine,novel amino acid amides from Staphylea pinnata L.

Two novel amino acids amides, pinnatanine and oxypinnatanine, have been isolated from Staphylea pinnata L. Their respective structures have been established as N⁵-(2-hydroxymethylbutadienyl)-l-allo-γ-hydroxyglutamine and N⁵-(3-hydroxymethyl-2,5-dihydro-2-furyl)-l-allo-γ-hydroxyglutamine by spectral methods and chemical degradation.     

Platinumolefin bond strength in Pt(PPh3)2(CH2CH2) and Pt(PPh3)2 {C(CN)2C(CN)2}

The enthalpy of the reaction: Pt(PPh₃)₂ (CH₂CH₂)(cryst.) + C(CN)₂C(CN)₂ (g) → Pt(PPh₃)₂ {C(CN)₂C(CN)₂}(cryst.) + CH₂ CH₂ (g) has been determined as ΔH₂₉₈=?155.8±8.0 kJ·mol^?1, from solution calorimetry. The interpretation, that the platinumethylene bond is much weaker than the platinumtetracyanoethylene bond, is contrary to conclusions drawn recently from electron emission spectroscopic studies, but in agreement with available structural data.     

Preparation and magnetic properties of manganite

A new hydrothermal synthesis of manganite is described, and the magnetic and electron paramagnetic resonance (EPR) behavior of the product is reported. The magnetic susceptibility is nearly independent of temperature above 90°K and increases dramatically on cooling to 30°K. The EPR lineshape, linewidth, and g-factor at 296°K are Lorentzian (in the central region), 280 ± 10 G, and 1.997 ± 0.006, respectively. The EPR spectrum is interpreted in terms of nearly one-dimensional interactions between identical Mn moments. The results of this study support the view that all Mn ions are trivalent and that the magnetic interactions between these ions are nearly one dimensional.