Reactivity of the Unsaturated Triosmium Cluster [Os3(CO)8{Ph2PCH2P(Ph)C6H4}(μ-H)] with Thiols

The reaction of the unsaturated cluster [(-H)Os₃(CO)₈{Ph₂PCH₂P(Ph)C₆H₄}] 2 with C₂H₅SH, CH₃CH(CH₃)SH and C₆H₅SH are reported. The reaction of 2 with C₂H₅SH yields the new complexes [Os₃(CO)₈(-SC₂H₅)(¹-SC₂H₅){Ph₂PCH₂P(Ph)C₆H₄}(-H)] 9 and [Os₃(CO)₈)(SC₂H₅)(Ph₂PCH₂P)(Ph)C₆H₄}] 8 in 24 and 57% yields respectively and the known compound [(Os₃(CO)₈)(-SC₂H₅)(-dppm)(-H)] 7 in 5% yield. Compound 9, which exists as two isomers in solution, converts into 8 almost quantitatively in solution at 25°C and more rapidly in refluxing hexane. Compound8 reacts with H₂ at 110°C to give 7 in high yield (86%). Treatment of 2 with propane-2-thiol yields [Os₃(CO)₈{-SCH(CH₃)CH₃}{Ph₂PCH₂P(Ph)C₆H₄}] 10 and [(Os₃(CO)₈{-SCH(CH₃)CH₃}{¹-SCH(CH₃)CH₃}{Ph₂PCH₂P(Ph)C₆H₄}(-H)] 11 in 75 and 3% yields respectively while with C₆H₅SH, [(Os₃(CO)₈(-SC₆H₅)(-dppm)(-H)] 6 is obtained as the only product in 75% yield. In both 8 and 10, the thiolato ligand bridges the Os–Os edge which is also bridged by the metallated phenyl group. The new compounds have been characterized by elemental analyses and spectroscopic methods (IR, ¹H and ³¹P NMR). The molecular structures of 7, 8, 9 and 10 are reported as determined by X-ray diffraction studies.     

Kinetic studies on the acid catalyzed reaction of hydroxamic acids in β-cyclodextrin/surfactant mixed systems

The acid catalyzed hydrolysis of two N-substituted hydroxamic acids (C₆H₅CON(OH)R, R = C₆H₅ (PBHA), R = C₆H₅CH₂(BBHA)) in mixed systems containing -cyclodextrin (—CD) and a surfactant (sodium dodecyl sulfate, SDS) has been studied. The reactions are inhibited by —CD. The inhibition is attributed to the formation of inclusion complex and competition between the micellization and complexation processes.This revised version was published online in December 2005 with corrections to the Cover Date.     

Reaction of triphenyl phosphite ozonide with thioacetals

Kinetic regularities in the reaction of triphenyl phosphite ozonide with several thioacetals in CH₂Cl₂ solution at –15°C have been studied. The consumption rate of ozonides is described by the kinetic equation W=k₀[(C₆H₅O)₃P·O₃]+k₁[(C₆H₅O)₃P·O₃][R₁R₂C(SR₃)₂] Rate constants k₀ and k₁ for the thioacetals: (CH₃H₇S)₂CH₂, (C₆H₅S)₂CH₂, (C₆H₅CH₂S)₂CH, (n=C₁₂H₂₅–S)₂CH₂, (C₃H₇S)₂C(H)CH₃, (C₃H₇S)₂C(H)C₆H₅, (C₃H₇S)₂C(CH₃)C₆H₅ and (C₃H₇S)₂C(H)C₁₀H₉, increases with increasing the electron-donating power of subtituents R_i.

---

CH₂Cl₂ –15°C. : W=k₀[(C₆H₅O)₃P·O₃]+k₁[(C₆H₅O)₃P·O₃][R₁R₂C(SR₃)₂] k₀ k₁ (C₃H₇S)₂CH₂, (C₆H₅S)₂CH₂, (C₆H₅CH₂S)₂CH₂, (n-C₁₂H₂₅S)₂CH₂, (C₃H₇S)₂C(H)CH₃, (C₃H₇S)₂C(H)C₆H₅, (C₃H₇S)₂C(CH₃)C₆H₅, (C₃H₇S)₂C(H)C₁₀H₉. .

     

Reactions of the Ru3(CO)10(μ-Ph2PCH2PPh2) cluster with enynes RCH=CHC≡CR (R is phenyl or ferrocenyl). Formation of indenone derivatives of triruthenium clusters

The thermal reaction of Ru₃(CO)₁₀(-Ph₂PCH₂PPh₂) (1) with enyne PhCH=CHCCPh afforded the trinuclear ruthenium clusters Ru₃(CO)₆{₃-P(Ph)CH₂PPh₂}{₃-C(Ph)=CHCC(Ph)(1,2-C₆H₄)C(=0)} (2), Ru₃(-H)(CO)₅{₃-P(Ph)CH₂PPh₂}{₃-C(Ph)=CHCC(Ph)(1,2-C₆H₄)C(—0)} (3), and Ru₃(CO)₆(-CO){₃-P(Ph)CH₂PPh₂}{₃-C(C=CPh₂)CH=C(H)Ph} (4) and also two isomers of Ru₃(CO)₅(-CO)(-Ph₂PCH₂PPh₂){₃-C₄Ph₂(CH=CHPh)₂} (5a and 5b). Clusters 2, 3, and 4 were characterized by IR spectroscopy, ¹H and ³¹P NMR spectroscopy, and X-ray diffraction analysis. The reaction of complex 1 with enyne FcCH=CHCCFc gave rise to the Ru₃(CO)₆{₃-P(Ph)CH₂PPh₂}{₃-C(Fc)=CHCC(Fc)(1,2-C₆H₄)C(=0)} (6) and Ru₃(-H)(CO)₅{₃-P(Ph)CH₂PPh₂}{₃-C(Fc)=CHCC(Fc)(1,2-C₆H₄)C(—0)} (7) clusters. According to the spectral data, the latter compounds are isostructural to complexes 2 and 3, respectively.     

The chemistry of cyclopentadienyl nitrosyl and related complexes of molybdenum,part 10(1). Cationic allyl complexes and attack thereon by nucleophiles

Summary The syntheses of [Mo(⁵-C₅H₅)(³-C₃H₄R)(CO)(NO)]⁺ (R=H, 1- or 2-Me) and [Mo(⁵-C₅H₅)(³-C₃H₅)(NCR)(NO)]⁺ (R=Me or Ph), by treatment of Mo(⁵-C₅H₅)(CO)₂(NO) with RC₃H₄Br and Ag⁺, and of Mo(⁵-C₅H₅)(³-C₃H₅)(NO)I with Ag⁺ in the presence of RCN, is described. Treatment of these cations with nucleophiles gives Mo(⁵-C₅H₅)(³-C₃H₅)(NO)X (X=halide, NCS or NCO), Mo(⁵-C₅H₅)(³-C₃H₅Q)(CO)(NO) (C₃H₅Q= propene ligand, Q= H, SCOMe, SEt, S₂CNMe₂, S₂CNEt₂, S₂CN(Bu-n)₂, C₅H₅, acac, OH, OMe or OAc), and [Mo(⁵-C₅H₅)(₂C₃H₅L)(CO)(NO)]⁺ (L=PEt₃, n-Bu₃P, PPh₃, PPh₂H, PMe₂Ph, C₅H₅N, 1-, 3- or 4-MeC₅H₄N and Me₂NNH₂). Reaction of [Mo(⁵-C₅H₅)(³-C₃H₅)(NCMe)(NO)⁺ with pyridine gave [Mo(⁵-C₅H₅)(³-C₃H₅)(pyr)(NO)]⁺, while treatment of [Mo(⁵-C₅H₅)(³-C₃H₅)(CO)(NO)]⁺ with PPh₃ in the presence of NaOEt afforded Mo(⁵-C₅H₅)(CO)(NO)(PPh₃). The¹H and¹³C n.m.r. spectra of these complexes are discussed particularly in relation to the occurrence ofexo andendo isomers of the allylic species. Comparison is made briefly between Mo(⁵-C₅H₅)(³-C₃H₅)(NO)I and Mo(C₅H₅)₂(NO)I.     

Synthesis and Crystal Structures of Copper(I) Complexes with N-Allylhexamethylenetetraminium Chloride Obtained in Different Acidic Media

The crystals of [(CH₂)₆N₄(C₃H₅)]Cu₂Cl₃ (I), [(CH₂)₆N₄(C₃H₅)]Cu₂Cl₃ (II), and [(CH₂)₆N₄(C₃H₅)]CuCl₂ (III) complexes were electrochemically synthesized (ac) from CuCl₂ · 2H₂O and N-allylhexamethylenetetraminium chloride in ethanol solutions at pH 6, 4.5, and 3. Their structures were determined using X-ray diffraction analysis (DARCh diffractometer, MoK radiation, /2 scan mode). Complex Icrystallizes in the monoclinic system: space group A2/a, a = 24.812(6) Å, b = 8.855(3) Å, c = 12.080(2) Å, = 89.21(3)°, and Z = 8. Complex II crystallizes in the triclinic system: space group P , a = 7.618(2) Å, b = 7.048(2) Å, c = 13.150(3) Å, = 97.50(2)°, = 92.70(2)°, = 100.74(2)°, and Z = 2. The crystals of complex III are orthorhombic: space group Pmn2₁, a = 7.478(2) Å, b = 8.827(2) Å, c = 9.662(3) Å, Z = 2. The organic cation in complex I acts as a tridentate ,,-ligand; that in complex II, as a bidentate ,-ligand. In complex III, the organic cation is involved in coordination with the copper(I) atom only through one nitrogen atom.     

A SACM study of the cross-combination ratio of rate constants

An analysis of the cross-combination ratio of the rate constants in terms of the statistical adiabatic channel model allows to factorize into two contributions: one due to the motion along the reaction coordinates and another due to the reaction transitional modes. for the CH₃/CCl₃, CH₃/C₂H₃, CH₃/C₃H₅, CH₃/C₂H₅ and C₂H₅/C₃H₅ radical pairs were calculated.     

Crystal and Molecular Structure of 5,7,12,14-Tetramethyl-1,4,8,11-tetraaza-4,6,11,13-tetraenatogold(III) Bromide [Au(C14H22N4)]Br

The crystal and molecular structure of [Au(C₁₄H₂₂N₄)]Br has been determined. Monoclinic crystals, a=12.592(2), b=6.309(1), c=19.628(2) ; =98.00(1)°, V=1544.1(4) ³, Z=4, d_calc=2.251 g/cm³, space group C2/c. The structure consists of virtually planar centrosymmetric [Au(C₁₄H₂₂N₄)]⁺ cations and Br^- anions. The coordination sphere of the gold atom involves four nitrogen atoms of the ligands, forming a planar square. The Au–N bond lengths are equal (the mean length is 1.982(7) ). The C–C and C–N bonds inside the -diiminate rings are delocalized. The parameters of the -diiminate rings of the [Au(C₁₄H₂₂N₄)]⁺ cation are compared with the parameters of the related complexes.     

Crystal structure and characterization of the bis(n-benzyl-benzotriazole-n3)-dichloro Co(II) complex: CoCl2(C6H4N3CH2Ph)2

The structure of [CoCl₂(C₆H₄N₃CH₂Ph)₂] has been determined by X-ray crystallography. It is also characterized by elemental analysis, IR and electronic spectroscopy, and by thermogravimetric differential thermal analysis. It crystallizes in the monoclinic system, space group C2/c, with lattice parameters a = 16.133(3) , b = 11.355(2) , c = 15.637(3) , = 117.22(3)°, and Z = 8. The crystal structure of the title compound consists of monomeric molecules of [CoCl₂(C₆H₄N₃CH₂Ph)₂] with slightly distorted tetrahedron geometry for the CoCl₂N₂ chromophore. The thermal gravimetry (TG) data indicate that there are four decomposition steps with five endothermic peaks. The final product of the thermal decomposition is CoCl₂. Elemental analysis and the electronic and IR spectra are in agreement with the structural data.Original Russian Text Copyright © 2004 by F. Jian, H. Wang, and H. XiaoTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 723–728, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Monte Carlo Studies of the Structural and Thermodynamic Properties of Some Smectic and Ferroelectric Liquid Crystals

Monte Carlo simulation based on the Gaussian overlap model was used to study the thermodynamic properties of smectic C: C₅H₁₁O–(OH)C₆H₃–CH=N–C₆H₄–C₅H₁₁ (A), C₁₀H₂₁O–C₆H₄–CH=CH–C₆H₄–OC₁₀H₂₁ (B), ferroelectric smectic C* liquid crystals (LC): C₇H₁₅O–C₆H₄–C₆H₄–COO–CH₂C*H(CH₃)C₂H₅ (C), C₈H₁₇O–C₆H₄–C₆H₄–C₂H₄C*H(CH₃)C₂H₅ (D), and an equimolar mixture of {A+C} and {A+D}. A system of N = 125 pairwise interacting ellipsoids of revolution placed in a volume V at a temperature T (that is, a system described by a canonical NVT-ensemble) is considered. These interactions were calculated using a specially devised Lennard-Jones potential, allowing for both mild anisotropic repulsion of particles (ellipsoids) and their dispersion attraction. Dipole–dipole interactions were also taken into account, since the molecules have highly polar groups: –O–, OH, CH=N, and COO and hence a high dipole moment (4.2-5.3 D). Calculations were carried out for a rectangular parallelepiped with periodic boundary conditions imposed on its faces. An elementary object of the NVT-ensemble was a two-molecule microcluster (dimer) but not a single molecule from the group under study. Smectic A ordering in the system has been unambiguously proven for different temperatures and fixed densities (0.32 0.44, where is the close packing coefficient). The ordering is attributed to the large (transverse) dipole moment inherent in molecules {A}-{D}. Temperature dependences of free energy, configuration energy, heat capacity C_v, and orientational order parameter were obtained. The curves agree well with the experimental data on variation of the properties of smectic LC.     

Radiation-Induced Transformations of Iron(II) Formate

The solid-phase decomposition of the iron formate crystal hydrate Fe(HCOO)₂ · 2H₂O under exposure to ⁶⁰Co -rays or 3.5-MeV electrons was studied. It was found that the irradiation of this salt to absorbed doses of 0.1–2 MGy resulted in the radiolysis of water of crystallization and the HCOO^– anion and in the reduction or oxidation of the Fe²⁺ cation. The composition of the solid-phase (-Fe, -Fe, FeO, -Fe -Fe₂O₃, Fe₃O₄, and FeCO₃) and gaseous (H₂O, CO, CO₂, HCOOH, and CH₄) radiolysis products of the substance was determined.     

4,4′-Bipyridine complexes of molybdenum(II) and tungsten(II)

Treatment of [MI₂(CO)₃(NCMe)₂] with two equivalents of 4,4-bipyridine (4,4-bipy) in CH₂Cl₂ at room temperature gave the MeCN displaced products, [MI₂(CO)₃(4,4-bipy-N)₂] (1) and (2). Equimolar amounts of [MI₂(CO)₃(NCMe)₂] and L (L = PPh₃, AsPh₃ or SbPh₃) react to give [MI₂(CO)₃(NCMe)L], which when reacted in situ with 4,4-bipy yield the new complexes, [MI₂(CO)₃(4,4-bipy-N)L] (3)–(8). Reaction of equimolar quantities of [WI₂(CO)(NCMe)( ²-RC₂R)₂] (R = Me or Ph) and 4,4-bipy gave the new bis(alkyne) complexes, [WI₂(CO)(4,4-bipy-N)( ²-RC₂R)₂] (9) and (10). Treatment of [MI₂(CO)₃(NCMe)₂] with two equivalents of (9) or (10) in CH₂Cl₂ at room temperature affords the bimetallic complexes, [MI₂(CO)₃{WI₂(CO)(4,4-bipy-N,N)( ²-RC₂R)₂}₂] (11)–(14). Equimolar quantities of [MI₂(CO)₃(NCMe)(PPh₃)] (prepared in situ) and (9) or (10), react to give the 4,4-bipy-bridged complexes, [MI₂(CO)₃{WI₂(CO)(4,4-bipy-N,N)( ²-RC₂R)₂}(PPh₃)] (15)–(18). All the new complexes, (1)–(18) were characterised by elemental analysis (C, H and N), i.r. and ¹H-n.m.r. spectroscopy.     

Migration of the η1:η6-C6H5Cr(CO)3 ligand into the cyclopentadienyl ring during metallation of the η5-C5H5(CO)2Fe η1:η6-C6H5Cr(CO)3 binuclear complex

It was found that the ¹⁶-C₆H₅Cr(CO)₃ ligand migrates into the cyclopentadienyl ring when the ⁵-C₅H₅(CO)₂Fe ¹⁶-C₆H₅Cr(CO)₃ binuclear complex is metallated with BuⁿLi. Under the same conditions, no migration of the phenyl ligand in the ⁵-C₅H₅(CO)₂Fe ¹-C₆H₅ complex was observed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 325–326, February, 1994.     

A study of the photochemistry and thermal chemistry of Ru3(CO)9(PR3)3{R = Ph,OMe} with two-electron donor ligands

The photochemistry of the tris-substituted clusters Ru₃(CO)₉(PR₃)₃ (R=Ph or OMe) with no added ligands, with CO, C₂H₄, alkynes and H₂ is compared and contrasted with results obtained for analogous thermal reactions. Photolysis of a CH₂Cl₂ solution of Ru₃(CO)₉(PPh₃)₃ leads to the metallated complex HRu₃(CO)₈(PPh₃)₂(PPh₂C₆H₄). In CCl₄, Ru(CO)₃(PR₃)Cl₂ is formed on photolysis of Ru₃(CO)₉(PR₃)₃. Photolysis of CO saturated solutions of Ru₃(CO)₉(PR₃)₃ leads to Ru(CO)₄(PR₃). C₂H₄ saturated solutions of Ru₃(CO)₉(PR₃)₃ generate the novel Ru(CO)₃(PR₃)(²-C₂H₄) complexes upon photolysis. With C₂H₂, photolysis of solutions of Ru₃(CO)₉(PR₃)₃ leads to the novel complexes Ru(CO)₃(PR₃)(²-C₂H₂). Substituted alkyne complexes have been prepared. Thermolysis of Ru₃(CO)₉(PR₃)₃ with HCCPh leads to the novel acetylide clusters HRu₃(CO)₆(PR₃)₃(₃-²-C₂Ph). With PhC CPh, only Ru₃(CO)₉{P(OMe)₃}₃ reacts, yielding the novel alkyne cluster Ru₃(CO)₆{P(OMe)₃}₃(₃-²-C₂Ph₂). With H₂, photolysis of CH₂Cl₂ solutions of Ru₃(CO)₉(PR₃)₃ leads to H₂Ru(CO)₂(PR₃)₂. Irradiating a 4:1 CH₂Cl₂ to EtOAc solution of Ru₃(CO)₉(PR₃)₃ under an atmosphere of H₂ leads to the novel dihydrido species H₂Ru₃(CO)₇(PR₃)₃. Thermolysis of H₂ saturated solutions of Ru₃(CO)₉(PR₃)₃ leads to H₄Ru₄(CO)₈(PR₃)₄.     

The electronic structure of molecules by a many-body approach

The vertical valence ionization potentials of cyclopropane, ethylene oxide and ethylene imine are calculated by a many-body Green's function method. For C₃H₆ the ordering of the ionization potentials is 2e(), 1e(), 2a₁(), 1a₂(), 1e(). The assignment of the 2a₁ and the 1a₂ ionization potentials which has been controversial is thus clarified. The ordering is in agreement with the result obtained via Koopmans' theorem. For ethylene oxide and ethylene imine Koopmans' theorem fails in predicting the correct order of ionic states. For C₂H₄O the ordering of the ionization potentials is 2b ₁(), 4a ₁, 1a ₂(), 2b ₂,3a ₁, 1b ₁(), 1b ₂, 2a ₁ and for C₂H₅N 6a, 5a, 3a, 2a, 4a, 3a, 1a, 2a. The agreement of the computed ionization potentials with the experimental values is very satisfactory.     

Novel tetrahedral and heteronuclear transition metal clusters prepared via single and double isolobal displacements

Ten transition metal cluster complexes with parent and substituted cyclopentadienyl ligands, [(⁵-C₅H⁴ CH₂CH₂)₂O][MFeCoS(CO)₈]₂ (2 M=Mo; 3 M=W), (⁵-C₅H₅)(⁵-RC₅H₄)MFeNiS(CO)₅ (5 M=Mo, R=Me; 6M= W, R=H), (⁵-C₅H₅)[⁵-C₅H₄C(O)CH₂]₂[WFeNiS(CO)₅][WFeCoS(CO)₈] (8), (⁵-C₅H₅)₂[⁵-C₅H₄ C(O)CH₂]₂[WFeNiS(CO)₅]₂ (9), (⁵-RC₅H₄)[(⁵-C₅H₄CH₂CH₂)₂O][Mo2FeS(CO)₇][MoFeCoS (CO)₈] (10R=MeCO; 12 R=MeO2C), (⁵-RC₅H₄)₂[(⁵-C₅H₄CH₂CH₂)₂O][Mo₂FeS(CO)₇]₂ (11 R=MeCO; 13 R=MeO2C), were synthesized through single and double isolobal displacements and characterized by elemental analyses, i.r., 1H-n.m.r. and MS techniques.     

19-Electron arenecyclopentadienyl complexes of ruthenium

A series of are necyc lope ntadienyl complexes,i. e., [Ru(⁵-c₅R₅)(⁶- are ne)]⁺ (1, R= H, arene = C₆H₆; 2, R = Me, arme = C₆H₆; 3, R = H, arctic = C₆H₃Me₃; 4, R = Me, arene = C₆H₃Me₃; 5, R = H, arene = C₆Me₆; 6, R = Me, arene = C₆Me₆) was studied by cyclic voltammetry. These compounds are capable of both oxidation and reduction. The reduction potential values depend on the number of methyl groups in the complex. Reduction of benzene complexes I and 2 by sodium amalgam in THF leads to the formation of decomplexation products, the addition of hydrogen to benzene, and dimerization of the benzene ligands. Both chemical and electrochemical reductions of mesitylene complexes3 and4 result in dimeric products [(⁵-C₅R₅)Ru(-⁵;⁵-Me₃H₃C₆H₃Me₃)Ru(⁵-C₅R₅)] (14, R = H; 15, R = Me). The action of sodium amalgam on compound5 gives products of hydrogen addition to both hexamethylbenzene (17) and cyclopentadienyl (18) ligands along with the major product, the dimer [⁵-C₅H₅)Ru(-⁵; ⁵-Me₆C₆C₆Me₆)Ru(⁵-C₅H₅)] (16). In contrast to5, its permcthylated analog 6 is only capable of adding hydrogen to the hexamethylbenzene ligand.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1691–1697, July, 1996.     

Synthesis and reactions of dicarbonyl (η2-indene)-η5-indenyl complexes of manganese and rhenium

Photochemical reactions of M(CO)₃(⁵-C₉H₇), where M=Mn (1) or Re (2), with indene have produced ²-indene complexes M(CO)₂(²-C₉H₈)(⁵-C₉H₇), where M=Mn (3) or Re (4). Deprotonation of complex3 witht-BuOK in THF at –60 °C gives the anion [Mn(CO)₂(¹-C₉H₇)(⁵-C₉H₇)^– (5), in which there occurs a rapid interchange of the Mn(CO)₂(⁵-C₉H₇) group between positions 1 and 3 in the ¹-indenyl ligand. The reaction of complex4 with Ph₃CPF₆ in CH₂Cl₂ at 0 °C leads to the complex [Re(CO)₂(³-C₉H₇)(⁵-C₉H₇)PF₆, whereas the similar reaction of complex3 gives only decomposition products even at –20 °C.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1280–1285, July, 1993.     

Cardiac glycosides of theCheiranthus allioni. XII

The seeds ofCheiranthus allioni hort. have yielded three new cardenolides the structures of which have been established and which have been named as 4-dehydrosarmentogenin (II), 4-dehydrosarmentogenin rhamnoside (I), and 4-dehydrosarmentogenin rhamnoglucoside (IV). (II) — C₂₃H₃₂O₅. m.p. 296–302°, [] _D ²⁰ +26.2±3° (in pyridine) is 3,11,14-trihydroxy-14-card-4,20(22)-dienolide. (I) C₂₉-H₄₂O₉, m.p. 268–275°, [] _D ²⁰ –38.2±3° (chloroform-ethanol) is 11,14-dihydroxy-3--L-rhamnopyranosyloxy-14-card-4,20(22)-dienolide.(IV) C₃₅H₅₂O₁₄, [] _D ^20D –44.1±3° (methanol), is 3-(4-O--D-glucopyranosyl--L-rhamnopyranosyloxy)-14-card-4, 20(22)-dienolide. An independent synthesis of 4-dehydrosarmentogenin (II) has been carried out, starting from 3,5,11,14-tetrahydroxy-5,14-card-20(22)-enolide, which has confirmed its structure.For Communication XI, see [1].All-Union Scientific-Research Drug Institute, Kharkov. Kharkov State Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 119–125, January–February, 1987.     

Dynamics of Hydrogen Bonds in Hydrogen Compounds of Period II Elements

The correlation energy diagrams of hydrogen compounds of Period II elements show that thehydrogen bond energy varies nonmonotonically along the period, passing through a minimum for CH₄, whichis consistent with the fact that this compound exhibits the properties of neither carbon hydride nor hydrogencarbide, is a parent compound for the organic chemistry. The degree of polymerization of liquid hydrogen fluoride was estimated from the correlation diagrams. The estimated degree of polymerization of thawedice is consistent with the known clathrate model of its structure.