Steroid glycosides from the starfishSolaster dawsoni (Verrill)

Two novel glycosides from the starfishSolaster dawsoni (Verrill) have been isolated and characterized: 24-O-(-D-xylopyranosyl)-5-cholestane-3,6,15,24,26-pentaol (solasteroside S₁) and (24R)-29-O-[-D-galactofuranosyl-(16)--D-galactofuranosyl]-24-ethyl-5-cholestane-3, 6,8,15,16,29-hexaol (solasteroside S₂).Translated fromIzvestiya Akademu Nauk. Seriya Khimicheskaya, No. 5, pp. 980–982, May, 1993.     

Triterpene glycosides from Pulsatilla chinensis

Four triterpene glycosides were isolated from the roots of Pulsatilla chinensis (Bunge) Regel (Ranunculaceae). Two new glycosides, chinensiosides A (1a) and B (2), were identified as 3-O-[-L-rhamnopyranosyl-(12)--L-arabinopyranosyl]-28-O-[-L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranosyl]-3,23-dihydroxylup-20(29)-en-28-oic acid and 3-O-{-L-rhamnopyranosyl-(12)-[-D-glucopyranosyl-(14)]--L-arabinopyranosyl}-28-O-[-L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranosyl]-3,23-dihydroxylup-20(29)-en-28-oic acid. The other two glycosides were identified as previously known hederasaponin C (3) from Hedera helix and glycoside III (4) from Pulsatilla cernua.     

Types of Inorganic Fluorocarbon Polymer Materials and Structure–Property Correlation Problems

The paper reviews published data on the structure and composition of two large classes of inorganic polymer fluorocarbon materials (IP FCMs), including hightemperature (HT) and lowtemperature (LT) modifications of graphite fluorides and fluorographitelike compounds CF _x (x = 0.5 – 1.12$) and CF_1+y (y = 0.08 – 1.33$) and intercalated fluorographite compounds (IFGCs) based on C _x F (x < 2) matrices. According to Xray diffraction data, C1s and F1s Xray photoelectron spectroscopy (XPS), ¹³C and ¹⁹F NMR, CK and FK Xray spectroscopy, and IR and Raman spectroscopy, as well as MNDO calculations, the structure of monolayers and the properties of IP FCMs of C₂F – CF_1+y composition depend on the combination of C(sp ³) – F fragments bonded to the sp ² fragments of the starting carbon matrices. The structure of hightemperature CF_1+y is specified by the presence of structurally isolated external and internal C(sp ³)F₂ groups located on the boundaries of C(sp ³) – F skeleton monolayers and in the holes of their nanostructures, respectively. The enthalpy of formation of HT FCMs does not depend on the type of starting carbon material and is linearly proportional to the F/C atomic ratio; C(sp ³)F and C(sp ³)F₂ groups are chemically indistinguishable in HT FCMs. Six models for the structure of C₂F and C₄F monolayers in LT FCMs are considered. The best agreement with spectroscopy and MNDO data is obtained using modified Yudanov–Gornostaev's model for C₂F, in which alternating rows of graphitelike sp ² carbon fragments coexist with rows of bonded perfluorocyclohexane sp ³ cells. For lowtemperature C₂₄F–C₂F, electric conductivity and C1s and F1s XPS data are generalized and composition–property diagrams are constructed. In this case, the conductivity, C1s and F1s XPS, and the interplanar distances in monolayers are explained using the concept of planarity of C _x F monolayers and the ensuing ideas of semiionic and semicovalent C=F bonds. For C₄F · yA–C₂F · zA compositions, ¹³C and ¹⁹F NMR data, C1s and F1s XPS, and IR data are accounted for by the predominant sp ³ nature of the structureforming C=F bonds.     

On the crystal chemistry of three copper(II)-arsenates: Cu3(AsO4)2-III,Na4Cu(AsO4)2, and KCu4(AsO4)3

The three copper(II)-arsenates were synthesized under hydrothermal conditions; their crystal structures were determined by single-crystal X-ray diffraction methods:Cu₃(AsO₄)₂-III:a=5.046(2) Å,b=5.417(2) Å,c=6.354(2) Å, =70.61(2)°, =86.52(2)°, =68.43(2)°,Z=1, space group ,R=0.035 for 1674 reflections with sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a=4.882(2) Å,b=5.870(2) Å,c=6.958(3) Å, =98.51(2)°, =90.76(2)°, =105.97(2)°,Z=1, space group ,R=0.028 for 2157 reflections with sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a=12.234(5) Å,b=12.438(5) Å,c=7.307(3) Å, =118.17(2)°,Z=4, space group C2/c,R=0.029 for 1896 reflections with sin / 0.80 Å^–1.Within these three compounds the Cu atoms are square planar [4], tetragonal pyramidal [4+1], and tetragonal bipyramidal [4+2] coordinated by O atoms; an exception is the Cu(2)^[4+1] atom in Cu₃(AsO₄)₂-III: the coordination polyhedron is a representative for the transition from a tetragonal pyramid towards a trigonal bipyramid. In KCu₄(AsO₄)₃ the Cu(1)^[4]O₄ square and the As(1)O₄ tetrahedron share a common O—O edge of 2.428(5) Å, resulting in distortions of both the CuO₄ square and the AsO₄ tetrahedron. The two Na atoms in Na₄Cu(AsO₄)₂ are [6] coordinated, the K atom in KCu₄(AsO₄)₃ is [8] coordinated by O atoms.Die drei Kupfer(II)-Arsenate wurden unter Hydrothermalbedingungen gezüchtet und ihre Kristallstrukturen mittels Einkristall-Röntgenbeugungsmethoden ermittelt:Cu₃(AsO₄)₂-III:a = 5.046(2) Å,b = 5.417(2) Å,c = 6.354(2) Å, = 70.61 (2)°, = 86.52(2)°, = 68.43(2)°,Z = 1, Raumgruppe ,R = 0.035 für 1674 Reflexe mit sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a = 4.882(2) Å,b = 5.870(2) Å,c = 6.958(3) Å, = 98.51(2)°, = 90.76(2)°, = 105.97(2)°,Z = 1, Raumgruppe ,R = 0.028 für 2157 Reflexe mit sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a = 12.234(5) Å,b = 12.438(5) Å,c = 7.307(3) Å, = 118.17(2)°,Z = 4, Raumgruppe C2/c,R = 0.029 für 1896 Reflexe mit sin / 0.80 Å^–1.Die Cu-Atome in diesen drei Verbindungen sind durch O-Atome quadratisch planar [4], tetragonal pyramidal [4 + 1] und tetragonal dipyramidal [4 + 2]-koordiniert; eine Ausnahme ist das Cu(2)^{[4 + 1]}-Atom in Cu₃(AsO₄)₂-III: Das Koordinationspolyeder stellt einen Vertreter des Übergangs von einer tetragonalen Pyramide zu einer trigonalen Dipyramide dar. In KCu₄(AsO₄)₃ haben das Cu(1)^[4]O₄-Quadrat und das As(1)O₄-Tetraeder eine gemeinsame O—O-Kante von 2.428(5) Å, was eine Verzerrung der beiden Koordinationsfiguren CuO₄-Quadrat und AsO₄-Tetraeder bedingt. Die zwei Na-Atome in Na₄Cu(AsO₄)₃ sind durch O-Atome [6]-koordiniert, das K-Atom in KCu₄(AsO₄)₃ ist [8]-koordiniert.

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Zur Kristallchemie dreier Kupfer (II)-Arsenate: Cu₃(AsO₄)₂-III, Na₄Cu(AsO₄)₂ und KCu₄(AsO₄)₃

     

The Coordination Number of Lu(III) in a Mixed System of Methanol and Water

The stability constants (_1(F)) of the monofluoro complex of Lu(III) and those (_1(Cl)) of the monochloride solvent-shared ion-pair of Lu(III) have been determined in mixed solvents of methanol and water at 0.10 and 1.00 mol·dm^–3 ionic strengths, respectively. The variation in ln_1(F) with an increase in the mole fraction of methanol (X _s) in the mixed solvent system showed an acute-angled convex inflection point at X _s 0.12, an acute-angled concave inflection point at X _s 0.22, and another acute-angled convex inflection point at X _s 0.27. It was concluded that the first and the second convex inflection points denoted the CN of Lu³⁺ from CN = 8 to a mixture of CN = 8 and 7 and from CN = 8 and 7 to a mixture containing CN = 6, respectively. The concave point is the starting point of a change in the CN of Lu(III) in LuF²⁺ from CN = 8 to a mixture of CN = 8 and 7. The values of two inflection points of the CN around Lu³⁺ are consistent with the inflection points of the variation in the values of ln_1(Cl) versus the dielectric constant of the mixed solvent.     

Complex polarizability as used to analyze dielectric relaxation measurements

The effect of representing dielectric properties in terms of the complex polarizability ^c = – i is examined. Loss curves ( and tan ) are shifted towards higher frequencies, revealing the existence of new relaxations and allowing the clarifications of ones already known. We have calculated the shift ratios (at maximum or tan )/ (at maximum or tan ) from the more conventional empirical equations representing the dielectric behavior. Some examples are given.     

Optisch aktive,aromatische Spirane, 11. Mitt.: Synthese optisch aktiver mono- bis heptasubstituierter 5-Methyl- und 5-Ethyl-2,2′-spirobiindane und analoger Naphthalinderivate bekannter Chiralität und enantiomerer Reinheit

Starting from optically active 5,5-dimethyl, diethyl, and 5-ethyl-5-methyl-2,2-spirobiindane as well as from 5-ethyl-spirobiindane-5-carboxylic ester of known enantiomeric purity and configuration 75 mono to polysubstituted 2,2-spirobiindanes have been prepared. Amongst these are several compounds with rings anellated in the 6,7 (and 6, 7) positions, especially a spirohydrocarbon4 x with orthogonal naphthalene units the circular dichroism of which is reported and discussed.Several mono and disubstituted 5-methyl and ethylindanes (1,2) have been prepared as models for synthetic transformations in the spirobiindane series.From the molar rotations of symmetrically diacylated 5,5-dimethyl and diethyl spirobiindanes (4a, 7b, 7c) empirical ligand parameters for acetyl and methoxycarbonyl were determined which gave much better results in the calculation of the rotations of appropriate spirobiindanes (with the shortened polynomal Ansatz) than the -values deduced previously from 5,5-disubstituted spirobiindanes. The significance of these results is briefly discussed.

10. Mitt.:Neudeck, H., Schlögl, K., Angew. Chem.92, 318 (1980), Intern. Ed. Engl.19, 308 (1980).     

Steroid compounds from the starfish Lysastrosoma anthosticta collected in the Sea of Japan

Six polyhydroxylated steroids and their derivatives were isolated from the starfish Lysastrosoma anthosticta collected in the Posyet Bay, Sea of Japan. These include a new glycoside of the steroid polyol, lysastroside A (1), which was identified as (25S)-26-O--d-xylopyranosyl-5-cholestane-3,6,8,15,16,26-hexaol, and the previously known pycnopodioside C monoglycoside (2), marthasterone sulfate (3), (25S)-5-cholestane-3,6,8,15,16,26-hexaol (4), (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (5), and (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (6). The compounds were tested for the haemolytic activity and the action on the embryogenesis of the sea urchin Strongylocentrotus intermedius.     

Evaluation of molten inorganic salt hydrates as reaction medium for the derivatization of cellulose

Molten inorganic salt hydrates are highly efficient solvents forcellulose. The carboxymethylation of the polymer dissolved in this new group ofcellulose solvents was investigated. The homogeneous carboxymethylation ofcellulose in molten LiClO₄3H₂O using sodiummonochloroacetate in the presence of NaOH is possible. The formation of CMC wasconfirmed by FT- Raman spectroscopy. Structure analysis by means of HPLC afterchain degradation showed the formation of CMC with a DS of 2 after a shortreaction time of 4 h. The derivatives exhibit a statisticaldistribution of substituents along the polymer chain if prepared in moltenLiClO₄3H₂O as solvent. A substituent distributioninthe order C-6 > C-2 C-3 for anhydroglucose units (AGU) was concludedfrom ¹H-NMR measurements. The synthesis of CMC in the swellingmediumLiClxH₂O (2 x 5) yields polymers with astatistical distribution of functional groups along the chain. The watercontentof the salt melts has a dramatic influence on the DS_CMC.     

Steroid polyols from the Far-Eastern starfish Henricia sanguinolenta

A new polyhydroxylated steroid (20R,24S)-5-cholestane-3,6,15,24-tetraol and a known glycoside, laeviuscoloside G, was isolated from the Far-Eastern starfish Henricia sanguinolenta, collected in the sea of Okhotsk, and characterized.     

Salicylaldehydo chelates of bis(cyclopentadienyl) zirconium(IV)

A new series of organometallic ionic chelates of the type [Cp ₂Zr(sal)]⁺ [ROCS₂/RRNCS₂]^–, where Hsal = salicylaldehyde;R =Me, Et, i-Pr ori-Bu andR =R =Me, Et, i-Pr;R =Me,R = benzyl orR =Et,R =m-tolyl, have been synthesized in aqueous medium by the reaction of [Cp ₂Zr(sal)]⁺Cl^– andROCS ₂ ^– K⁺/RRNCS ₂ ^– Na⁺. These compounds have been characterized by chemical analyses, electrical conductance, electronic, IR and¹H-NMR spectral studies. These studies indicate that the complexes are 1:1 electrolytes and the salicylaldehyde ligand is chelating in all these complexes. Therefore, a tetrahedral coordination about the zirconium atom is proposed.

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Salicylaldehydo-Chelate von Bis(cyclopentadienyl)-zirkonium(IV)

Zusammenfassung Eine neue Gruppe von organometallischen ionischen Chelaten vom Typ [Cp ₂Zr(sal)]⁺ [ROCS₂/RRNCS₂]^– (mit Hsal = Salicyladehyd;R =Me, Et, i-Pr oderi-Bu undR =R =Me, Et, i-Pr;R =Me,R = Benzyl oderR =Et,R =m-Tolyl) wurde in wäßrigem Medium mittels der Reaktion von [Cp ₂Zr(sal)]⁺Cl^– mitROCS ₂ ^– K⁺/RRNCS ₂ ^– Na⁺ hergestellt. Die erhaltenen Verbindungen wurden mittels chemischer Analyse, elektrischer Leitfähigkeit und der IR- sowie¹H-NMR-Spektren charakterisiert. Diese Untersuchungen zeigen, daß die Komplexe 1:1-Elektrolyte sind, wobei der Salicylaldehyd-Ligand in allen Fällen an der Chelatbildung beteiligt ist. Es wird daher für das Zirkoniumatom eine tetrahedrale Koordination vorgeschlagen.

     

The Molecular Structure and NMR Properties of P-Phosphinoylmethyl Aminophosphonium Salts

The molecular structures of two aminophosphonium salts (bromide and tetrafluoroborate) have been determined by X-ray analysis. They have similar conformations and hydrogen bond (HB) networks: the N–H acid proton is bonded to the anion and, in the case of the fluoroborate, to the oxygen atom of the phosphine oxide, forming a pseudo six-membered ring closed by a weak N–HO intramolecular hydrogen bond (IMHB). These compounds have been studied by multinuclear NMR in solution, including the ¹⁵N-labeled derivatives, to determine a complete set of coupling constants. A coupling of 1.5 Hz between the ¹⁵N and the ³¹P nuclei, separated by three bonds, was observed experimentally for the bromide in CDCl₃ solution, which appears to be a classical ³ J _N-P across the covalent bonds and not a ^3h J _N-P across the IMHB.     

Thermal transformations of α-H6P2Mo18O62·nH2O heteropolyacid

According to the ³¹P NMR spectroscopy, heteropolyacid (HPA) H₆P₂Mo₁₈O₆₂·nH₂O (P₂Mo₁₈), -isomer of the Dawson structure, transforms upon heating above 80 °C partially (up to 30%) to -isomer, in which both polar groups Mo₃O₁₃ of the heteropolyanion are turned by 60° around the N₃ axis, and partially to -isomer in which only one group is turned. The - and -isomers of P₂Mo₁₈ have been found for the first time. Their transformation into the -isomer occurs upon rehydration in one week in air and in 1 h in an aqueous solution. HPA P₂Mo₁₈ decomposes on heating up to 350 °C to HPA H₃PMo₁₂O₄₀ (PMo₁₂) and a previously unknown phase of the HPMo₆I₂₁ composition, which in its turn decomposes at 375 °C to molybdenyl phosphates and IiI₃. The PMo₁₂ decomposition occurs via two routes to form the same products at temperatures of 400 and 450 °C with corresponding exotherms of IiI₃ crystallization.     

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXXVI Structural Studies in the Copper(I) Halide : Norbornadiene System

The structural characterizations of some copper(I) halide (CuX) adducts with norbornadiene (nbd) are recorded. CuCl : nbd (1:1)₄ (a redetermination), (2:1)_2(|), are systems both based around Cu₄Cl₄ cubane-type cluster arrays. CuBr : nbd (7:3)_(|)( 0.5 MeOH), a complex polymer with 3-symmetry, is believed to be the complex previously described as an adduct of 2:1 stoichiometry. Attempts to obtain an iodide counterpart have resulted in the definition of an ephemeral adduct CuI : MeCN (3:2)_(|). 0.5 C₇H₈ in which, remarkably, the nbd is uncoordinated; the complex is a polymer, related to the [AgX(quinoline)]_(|) (X = Cl, Br) saddle polymer.     

Triterpene Glycosides of Tragacantha Stipulosa and Their Genins. Structures of Askendosides G and D and Cycloglobiceposide B from One- and Two-Dimensional 1H and 13C NMR Spectroscopy

Roots of Tragacantha stipulosa Boriss yielded three triterpene glycosides of the cycloartane series: askendoside G (1), askendoside D (2), and cycloglobiceposide B (3). Glycoside 1 is 3-O--L-arabinopyranosyl-(12)--D-xylopyranoside; 16-O--D-glucopyranoside-24R-cycloartan-3,6,16,24,25-pentaol; 2 - 3-O--L-arabinopyranosyl-(12)--D-xylopyranoside; 6-O--D-xylopyranoside-20R,24S-epoxycycloartan-3,6,16,25-tetraol; 3 - 3-O--D-xylopyranoside; 16-O--D-glucopyranoside; 25-O--D-glucopyranoside-24R-cycloartan-3,6,16,24,25-pentaol.     

Redox Properties of Rhodium(III) Oxo-Bridged Carboxylate Complexes

Chemical and electrochemical oxidation of rhodium (III) oxo-bridged carboxylate complexes was studied. The chemical [with O₃ and Ce(IV) salts] or electrochemical (at potentials of 1.00-1.20 V) oxidations of the binuclear complexes [Rh₂(-O)(-O₂CCH₃)₂(H₂O)₆]^{2 +} and [Rh₂(-O)(-O₂CCF₃)₂(H₂O)₆]^{2 +} leads to the superoxo complexes [Rh₂(-O)(O₂-)(-O₂CCH₃)₂(H₂O)₅]⁺ and [Rh₂(-O)(O₂ ^-)(-O₂CCF₃)₂(H₂O)₅]⁺ with terminal coordination of O₂-. The trinuclear acetate [Rh₃(₃-O)(-O₂CCH₃)₆(H₂O)₃]⁺, unlike its trifluoroacetate analog [Rh3(₃-O)(-O₂CCF₃)₆(H₂O)₃]⁺, is oxidized only electrochemically at a potential of 1.38 V. The oxidation of [Rh₃(₃-O)(-O₂CCH₃)₆(H₂O)₃]⁺ is reversible and involves formation of an unstable superoxo group O₂ ^- between two Rh₃III(₃-O) cores.     

Generalized quantum mechanical two-centre problems. IV. On the accuracy of simple LCAO approximations for H 2 + states and the Eckart criterion

If x denotes an exact solution of the quantum mechanical two centre Coulomb problem, we optimize a normalized LCAO approximation by making the overlap S = (x¦) a maximum. In this context we study how a weight factor (r _a r _b )^–1 in the definition of the inner product changes the approximation and the expectation value of electronic energy. Finally we compare the lower bound given by the Eckart criterion with the exact overlap. Results are reported for H ₂ ⁺ states 1s_g and 2p_u.Dedicated to Professor Hermann Hartmann on occasion of his 70th birthday on May 4th, 1984     

Predissociation lifetime of the 1σ g 2 2σ g diabatic state of He 2 + : a one-channel approach

Summary This work is concerned with the application of a one-channel model to obtaining predissociation lifetimes and transition rates in a system of crossing diabatic states. The calculation focuses on the first shape resonance of the 1 _g ² 2 _g diabatic state of He ₂ ⁺ , which is relatively stable with respect to tunneling. This resonance predissociates as a result of the 1 _g ² 2 _g state being crossed by the 1 _g 1 _u ² dissociative diabatic state near the resonance level. We have estimated its predissociation lifetime to be of the order of 10^–11 s.