Effect of the form and the parameters of intermolecular interaction potential on calculated values. Henry constant for adsorption of noble gases on graphitized black and the specific surface area determined therefrom

The effect of the form and the parameters of the atom-atom potential of intermolecular interaction, as well as that of the approximations used in its summation over the atoms of a solid, on the values of the Henry constant $\text{K}$₁ for the adsorption of noble gases on the basal face of graphite has been examined. At fixed values of the depth and of the position of the atom-atom potential minimum, $\text{K}$₁ values are only slightly sensitive to the form of this potential, if its summation is performed taking into account the layer structure of graphite. Disregarding the laminated structure of the graphite lattice leads to highly underestimated values of $\text{K}$₁. The values of the parameter $\text{c}$₁ of the attractive forces of the potential (6, 8, exp) for the intermolecular interaction of the atoms of noble gases with the carbon atom of graphite have been determined, using experimental values of $\text{K}$₁ for the adsorption of these gases on graphitized thermal carbon blacks. The corresponding changes in internal energy, entropy and heat capacity have been calculated.The effect of the form and the parameters of the potential function φ of the intermolecular interaction of a monoatomic molecule with the basal face of graphite on the energy φ_o in the minimum of the potential curve φ($\text{z}$), and on the product $\text{sz}$_o of the specific surface area $\text{s}$, and the equilibrium distance between the molecule and the surface $\text{z}$_o, has been studied. φ_o and $\text{sz}$_o were determined from experimental values of the Henry adsorption constant $\text{K}$₁ measured at different temperatures. From the experimental values of $\text{K}$₁ for the adsorption of noble gases, the value of $\text{s}$ for graphitized thermal carbon black Sterling PT, 2700 (P-33), has been determined. This value of $\text{s}$ does not essentially depend on the adsorbate and lies within the limits of error of the $\text{s}$ value, determined for this carbon black by the BET method. When determining $\text{s}$ from $\text{K}$₁, it is necessary to take into account the structure of the solid so as to choose the form of potential φ correctly. Values of $\text{z}$_o should be determined from the atom-atom potential function of the adsorbate-adsorbent intermolecular interaction.     

Nitroindolenines en serie vincadifformine : intermediaires d'acces a la vincamone et a un squelette azahomoaspidospermane

Vincadifformine and its 10-substituted analogs give in good yields 16-nitro indolenines of which the reactivity has been studied. By a two step process (demethoxycarbonylation and chloration on C16) nitro-indolenine $\text{2b}$ leads to gem-chloro-nitro $\text{6}$. By an other two step sequence (NaBH₃CN, NaH) nitro-indo-lenine $\text{2c}$ yields compound $\text{10}$ via a 16 → 1 COOCH₃ migration. By heating compounds $\text{6}$ and $\text{10}$ in CF₃COOH, rearranged products are obtained : vincamione $\text{5}$ from $\text{6}$ and azahomoaspidospermane $\text{13}$ from $\text{18}$. Mechanisms of formation of $\text{5}$, $\text{10}$ and $\text{13}$ are discussed.     

Gracilin A,an unique: nor-diterpene metabolite from the marine sponge spongionella gracilis.

From the marine sponge $\text{Spongionella gracilis}$ a novel degraded C₁₉ terpene diacetate ($\text{2}$) has been isolated and its structure elucidated by spectral analysis, including 2D-NMR, and chemical evidence.     

Biomimetic synthesis of bacterial c50 carotenoids decaprenoxanthin and c.p. 450

Alkylation of the distal double bond of pseudoionone $\text{4}$ has been carried out with isoprene epoxide (ZnCl₂ /MeNO₂ ) leading directly to α-$\text{cis 10 a}$, α-$\text{trans}$$\text{10b}$ and γ $\text{10c}$ hydroxyprenylionones. The α-$\text{cis}$ and γ-isomers have been converted in few steps into the C₅₀ carotenoids decaprenoxanthin $\text{1}$ and C.p. 450 $\text{3}$ respectively.     

Stereo structure of norkhusinoloxide,a new ntipodal C14 terpenoid from vetiver oil. Confirmation of stereostructural features by biological evaluation,a new tool for prediction of stereostructure in cadinanes

From the alcoholic fraction of North Indian vetiver oil ($\text{Vetiveria}$$\text{zizanioides}$) a new C₁₄ terpenoid, norkhusinoloxide has been isolated. Stereostructure has been assigned to it on the basis of chemical correlation coupled with spectral data. This stereostructure was further confirmed on the basis of the comparison of its plant growth activity with that displayed by khusinol oxide of known stereostructure. It is the first report where biological evaluation has been used as a tool to confirmstereo structure of a naturally occurring terpenoid.     

The structure of tatsinine,a novel c19-diterpenoid alkaloid from delphinium tatsienense franch

A novel C₁₉-diterpenoid alkaloid designated as tatsinine has been isolated from the roots of $\text{Delphinium}$$\text{tataienence}$ and its structure (3) has been derived from ¹H NMR and ¹³C NMR spectroscopic evidence.     

Heat capacity and thermodynamic properties of ramsdellite,Li2Ti3O7, and spinel,Li43Ti53O4

The heat capacity and heat content Li_{$\text{4}\text{3}$}Ti_{$\text{5}\text{3}$}O₄ and Li₂Ti₃O₇ have been measured in the temperature range 198—960 K. The lattice and dilation contributions to the heat capacity have been estimated. The standard thermodynamic functions and the high temperature enthalpy and entropy have been derived. The lattice heat capacity of Li_{$\text{4}\text{3}$}Ti_{$\text{5}\text{3}$}O₄ spinel appears to be consistent with the phonon model put forward by Grimes.     

Isolation of aspirochlorine (=antibiotic A30641) possessing a novel dithiodiketopiperazine structure from Aspergillus Flavus

A very unusual dithiokikeptopiperazine structure ($\text{1}$) has been assigned to aspiroclorine, C₉H₁₂N₂O₅S₂Cl, produced as a biologically active substance together with canadensolide by $\text{Aspergillus}$$\text{flavus}$, which has been found to be identical with the antibiotic A 30641 from $\text{A.}$$\text{tamarii}$.     

Organomercury compounds XX Reactions of lithium polyfluorobenzenesulphinates with mercuric salts

The lithium polyfluorobenzenesulphinates, Li O₂SR (R = C₆F₅, $\text{p}$-HC₆F₄, $\text{m}$-HC₆F₄, or $\text{o}$-HC₆F₄), and the dilithium tetrafluorobenzenedisulphinates, $\text{p}$- and $\text{o}$-(LiO₂S)₂C₆F₄, have been prepared by reaction of the appropriate polyfluoroaryllithium compounds with sulphur dioxide. All compounds were isolated as hydrates and gave the corresponding $\text{S}$-benzylthiouronium salts on treatment with $\text{S}$-benzylthiouronium chloride. From reactions of the lithium sulphinates with suitable mercuric salts in water, generally at room temperature, the derivatives RHgX (R = C₆F₅, X = Cl, Br, CH₃CO₂, or PhSO₂; R = $\text{p}$-HC₆F₄, X = Cl, Br, or CH₃CO₂; R = $\text{m}$-HC₆F₄, X = Cl or Br; R = $\text{o}$-HC₆F₄, X = Cl), $\text{p}$-(XHg)₂C₆F₄ (X = Cl, Br, or CH₃CO₂), and $\text{o}$-(XHg)₂C₆X₄ (X = Cl or Br) have been prepared. Similarly, the bispolyfluorophenylmercurials R₂Hg (R = C₆F₅, $\text{p}$-HC₆F₄, or $\text{m}$-HC₆F₄) have been prepared from the corresponding lithium sulphinates and either mercuric salts or polyfluorophenylmercuric halides in aqueous $\text{t}$-butanol. A possible mechanism for the sulphur dioxide elimination reactions is discussed.     

Cyclisatioh de diarylalcanes en milieu superacide : synthese de cetones tricycliques a methyle angulaire et mecanisme de leur isomerisation

Cyclisation of readily available diary1-1,2 ethanes $\text{1→4}$ proceeds in SbF₅,-HF at 0°C to yield tricyclic phenanthrenones $\text{5}$, $\text{6}$, $\text{7}$ and $\text{11}$ bearing an angular methyl group. This process implies the electrophilic attack of the more basic aromatic ring, reacting through its diprotonated form (on the oxygen and the meta carbon atom) on the second aromatic ring. Isomerization of these primary products may be observed to give ketones $\text{8}$, $\text{9}$, $\text{10}$ from $\text{3}$ and $\text{12}$ from $\text{4}$) and it has been demonstrated by the use of specifically deuterated $\text{3d}$ that it involves stereospecific 1,2 hydride (or deuteride) shifts, without exchange.     

Ichthyotoxic sesterterpenoids from the neo guinean sponge carteriospongia foliascens

Six 20,24-dimethylscalarane derivatives ($\text{5}$, $\text{12}$, $\text{15}$, $\text{17}$, $\text{19}$, and $\text{21}$) have been isolated from the Neo Guinean sponge Carteriospongia foliascens. Compound $\text{12}$ is identical with a C₂₇ tetracyclic terpene previously isolated from an Australian specimen of the same sponge. The five other derivatives are new and their structures have been established on the basis of their spectral data. The structure of $\text{5}$ was confirmed by single-crystal X-ray diffraction and that of $\text{15}$ by chemical correlation with $\text{12}$. The configuration at C-4 for all these compounds has been determined through ¹³C NMR data. Evidence leading to reverse the configuration at this centre in previously reported C₂₇ tetracyclic terpenes is discussed. An ecological function is suggested for these molecules.     

Nematic—isotropic solution thermodynamics in di(p-methoxyphenyl)-trans-cyclohexane-1,4-dicarboxylate

Solution thermodynamic parameters of selected non-polar solutes have been determined in the nematic and isotropic fluid states of di(p-methoxyphenyl)-trans-cyclohexane-1,4-dicarboxylate. These states have been reported to exert no measurable differential in kinetic medium effects on the Claisen rearrangement¹. Partial molar enthalpies Δ$\text{H}$^soln₂ and entropies Δ$\text{S}$^soln₂ of solution of a series of substituted benzenes in the nematogenic solvent, determined by the gas—liquid chromatographic method of Martire, ^2–4, are reported. Changes in solute excess Gibbs free energy Δ$\text{G}$^E₂ over the nematic—isotropic transition of the solvent, corresponding to the changes in free energy of solution ΔΔ$\text{G}$^soln₂, have been calculated for the series. The results show the nematic and isotropic states of the medium to exhibit distinctly different solvent characteristics and suggest that Claisen reaction kinetics in the nematogenic solvent reflect compensating medium effects on the reactant and its activated state.     

Nucleophilic reactions of fluoroolefins. II. Regioselectivity and elimination-addition competition in the reaction of 1-phenylpentafluoropropenes with sodium ethoxide

1-Phenylpentafluoropropene and its para-substituted analogs $\text{1}$ are susceptible to nucleophilic attack at both vinylic carbon atoms C-1 and C-2. They react with ethanolio sodium ethoxide to give predominantly substitution products, 1-ethoxy-1-phenyltetrafluoropropenes $\text{2}$ and 2-ethoxy-1-phenyltetrafluoropropenes $\text{3}$, with only little formation of adducts, $\text{viz}$. 2-ethoxy-1H-1-phenylpentafluoropropanes $\text{4}$. Alkenes $\text{1}$, where the para-substituent X  H,Cl,and CF₃ give additionally 1,2-diethoxy-1-phenyltrifluoropropenes $\text{5}$ and, where X = CF₃ also 2,2-diethoxy-1H-1-phenyltetrafluoropropane $\text{6}$. Overall regioselectivity of nucleophilic attack of the ethoxide ion on alkenes $\text{1}$ exhibits the Hammett type correlation with Ó_p values of substituents X: CH₃O and CH₃ groups favour the attack on the vinylic carbon C-1, while CF₃ and Cl substituents direct the attack on the C-2 carbon of alkenes $\text{1}$. The E and Z isomers of 1-ethoxy and 1,2-diethoxy substituted alkenes $\text{2}$ and $\text{5}$ were formed in comparable amounts, while the E isomers of 2-ethoxy substituted alkenes $\text{3}$ were always formed with a 93 – 97 % selectivity.     

The spin 32 state (?) in six-coordinate iron (III). A Mössbauer and EPR investigation

Tris-(4-morpholinecarbodithioato-S,S′) iron (III) (FeM) and its dichloromethane solvate, (FeM·CH₂Cl₂), have been prepared and their temperature-dependent Mössbauer and EPR spectra have been determined at temperatures between liquid nitrogen and ambient. The Mössbauer spectra of FeM·CH₂Cl₂ differ considerably from that of FeM and is interpreted in terms of a four-line spectrum at 77 K. The EPR spectra of the two complexes indicate that the lower spin state of FeM·CH₂Cl₂ populates much more rapidly in the temperature range studied (100–300 K) than does FeM. These results support the postulation of an S = $\text{5}\text{2}$ ? S = $\text{1}\text{2}$ spin-equilibrium for FeM and a corresponding S = $\text{5}\text{2}$ ? S = $\text{3}\text{2}$ equilibrium for FeM·CH₂Cl₂.     

Substituent influence on the indolization with pcl3 of some o,m,p-substituted phenylhydrazones

The indolization of deoxybenzoin $\text{o}$,$\text{m}$,$\text{p}$ (Me, MeO, Cl), $\text{p}$-NO₂ and $\text{m}$-EtO-phenylhydrazones (1) by the above reaction has been examined. All the reactions are carried out at room temperature and high yields of the corresponding indoles (2) are obtained even when -NO₂ substituent is present. In this case longer reaction time is necessary. Alkoxyphenylhydrazones give the corresponding indoles (2) in high yields without showing collateral reactions which indeed are present in several Fischer routes on these derivatives. $\text{m}$-Substituted phenylhydrazones (1) give a mixture of 4- and 6-substituted indoles in which the 6-isomer is always prevalent, a feature not inherent in the Fischer reactions. The regioselectivity is enhanced by the substituent steric hindrance increasing. The reaction can be also carried out at 0°C with a further improvement of its regioselectivity.     

Confirmation of 2,6,10,15,19-pentamethyleicosane in methanogenic bacteria and sediments

A C₂₅ alkane (1) proposed previously to occur in $\text{Methanobacterium barkeri}$ and $\text{M. thermoautotrophicum}$¹ and to be a sedimentary biological marker for methanogenic bacteria⁹, has been synthesised and its occurrence confirmed.     

N-halogeno-compounds. Part 9 [1]. Azoxy- and azo-arenes derived from 4-(dichloroamino)tetrafluoropyridine; crystal structure of trans-2,3,5,6-tetrafluoro-4-(2,4,6-trimethylphenyl-onn-azoxy)pyridine

The nitrosoarenes ArNO (Ar = C₆H₅, 2-MeC₆H₄, 2,4,6- Me₃C₆H₂ and C₆F₅) have been condensed with 4-(dichloroamino)- tetrafluoropyridine to provide the azoxy-compounds py_FN$\text{N}\text{+}$($\text{N}\text{-}$)Ar (py_F = 2,3,5,6-tetrafluoro-4-pyridyl); de-oxygenation of the first three with triphenylphosphine or triethyl phosphite gave the corresponding azo-compounds, and the reverse reaction was achieved in the case of py_FNNC₆H₂Me₃-2,4,6 using peroxytrifluoroacetic acid. Thermolysis of 4-azidotetrafluoropyridine in the presence of pentafluoronitrosobenzene provided the perfluorinated azoxy-compound py_FN$\text{N}\text{+}$($\text{O}\text{-}$)C₆F₅. X-Ray methods have been used to determine the molecular geometry of py_FN$\text{N}\text{+}$($\text{O}\text{-}$)C₆H₂Me₃-2,4,6.     

Acid-base reactions of 1,3,4-thiadiazolines and thiocarbonyl ylides; 1,3,4-thiadiazoline-2-spiro-2′-adamantane

The surprising formation of C₂₂H₃₂N₂S₂ from the title compound 1 at 45°C involves the interaction of the basic adamantanethione S-methylide ($\text{2}$) with its acidic precursor $\text{1}$, in the course of which the anion $\text{6}$ undergoes electrocyclic ring opening; the acid and base functions offer the clue to a prolific chemistry of the thiadiazoline $\text{1}$ and the thiocarbonyl ylide $\text{2}$.     

Molecular predissociation dynamics revealed through multiphoton ionisation spectroscopy. I. The C1B1 states of H2O and D2O

The $\text{C}$¹B₁ states of H₂O and D₂O have been observed by means of three photon absorption (four photon ionisation) spectroscopy. Differences between the experimentally observed 3 + 1 multiphoton ionisation spectrum and that predicted by the appropriate asymmetric-top three-photon line-strength theory are attributed to $\text{C}$ state predissociation. Two separate predissociation mechanisms have been identified, one (heterogeneous) relying on a-axis parent molecular rotation to couple the bound B₁ state to an unbound state of A₁ electronic symmetry, the other (homogeneous) involving a second, dissociative excited electronic state of B₁ symmetry. Having established the detailed $\text{C}$ state predissociation dynamics, two photon absorption spectra of H₂O and D₂O ($\text{C}$ ← $\text{X}$) can be predicted accurately: studies of individual quantum-state-selected photofragmentation processes from H₂O($\text{C}$) are proposed.     

Note on a theoretical interpretation of the isotopic ratio vOH/vOD versus vOH in isotopically diluted HDO molecules in solid hydrates

A simple intra- and inter-molecular potential for water molecules engaged in hydrogen bonding has been used in a one-dimensional approximation for a theoretical interpretation of the experimental correlation $\text{v}$_OH/$\text{v}$_OD versus $\text{v}$_OH in solid hydrates. The variation in the equilibrium OH(D) distance has also been considered.