Stereoselective Inclusion and Structure of Equatorial-trans-1,2-dichlorocyclohexane

Abstract

Optically active (R,R)-(-)-trans-1,2-dichlorocyclohexane (DCC) was isolated as an inclusion crystal with the optically active host, (R,R)-(-)-trans-2,3-(hydroxydiphenylmethyl)-1,4-dioxaspiro[4.4]-nonane, and the structure of the 2:1 inclusion crystal has been determined by X-ray analysis. Crystal data: C₇₂H₇₄O₈Cl₂, orthorhombic, P2₁2₁2 (No. 18), a = 17.465(6) Å, b = 20.095(6) Å, c = 8.664(5) Å, V = 3040(2) ų, Z = 2, D_c = 1.24g cm^?3, D_m = 1.23g cm^?3, T = 293 K and final R ₁ = 0.050 for 2766 observed data (I > 2σ(I)). The conformation of DCC in the inclusion crystal has been found to be equatorial and the absolute configuration was definitely determined to be (R,R) on the basis of the known configuration of the host.     

The Structure of 2‐[(1S)‐(+)‐10‐camphorsulfonamino]‐6‐aminopyridine in the Solid State and in Solution; Unprecedented Cocrystallization of Four Stereoisomers

The solid and solution structures of a new optically active aminopyridine compound, 2‐[(1S)‐(+)‐10‐camphorsulfonamino]‐6‐aminopyridine [(S)‐csaap], 1 , are reported. Crystal data: space group P2₁, a = 8.9729 (5), b = 10.9447 (6), c = 36.693 (2) Å, β = 96.435 (1)°, V = 3580.8 (3) ų, Z = 8, R₁ = 0.0673 and wR₂ = 0.1600 with I > 2σ(I). This chiral compound shows an unprecedented cocrystallization of four stereoisomers, which are characterized by X‐ray crystallography and NMR spectroscopy.     

Absolute configuration of (+)‐(S)‐2‐(5‐fluoro‐2‐methoxy‐1,4‐benzodioxan‐2‐yl)­imidazolinium bromide

The title compound, C₁₂H₁₄FN₂O₃⁺·Br^?, crystallizes in the non‐centrosymmetric P2₁2₁2₁ space group. The absolute configuration of the pharmacologically active mol­ecule could be resolved in the hydro­bromide salt, the structure of which is reported. The mol­ecule of the title compound has the S configuration. The molecular packing in the crystal is stabilized by weak N—H?Br [N?Br = 3.240 (4) and 3.302 (4) Å] hydrogen bonding.     

Evidence for the Solid State Structural Transformation of the Network-Type Decavanadate (NC7H14)4[H2V10O28] into a Lamellar Topology (NC7H14)[V4O10]

The hydrothermal synthesis and the structural determinations of two vanadium oxides interleaved by quinuclidinium cations are described; (NC₇H₁₄)₄[H₂V₁₀O₂₈] is an anhydrous diprotonated decavanadate (triclinic, P 1 (n° 2), a = 9.701(1) Å, b = 10.839(1) Å, c = 12.7566(2) Å, α = 109.13(1)°, β = 112.09(1)°, γ = 92.17(2)°) and (NC₇H₁₄)[V₄O₁₀] a layered compound (orthorhombic, C mcm (n° 63), a = 18.4461(5) Å, b = 6.6619(2) Å, c = 11.7967(2) Å). Thermodiffractometry shows that the decavanadate irreversibly transforms at 230 °C into the layered compound without any amorphous intermediate state.     

Crystal and molecular structure and the absolute configuration of N-phenyl-N′-(1-phenylethyl)methanephosphonodiamidate

The structural investigation of the product of the reaction of methanephosphonodichloridate with R(+)-1-phenylethylamine and aniline in the presence of triethylamine [3] was performed. The obtained compound C₁₅H₁₉N₂OP ( 1 ) crystallizes in monoclinic system, space group P2₁ with a = 10.466(1) Å, b = 6.984(3) Å, c = 10.471(2) Å, β = 95.43(1)°, V = 762.0(9) ų. Z = 2, and R = 0.037. The absolute configuration at the P and C8 atoms was determined by means of X-ray crystallography as R_p and R_c8, respectively.     

Crystal and molecular structure and determination of absolute configuration of two enantimers of methoxycarbonylmethyl carboxymethyl sulfoxide

Crystal and molecular structures of two enantiomers of methoxycarbonylmethyl carboxymethyl sulfoxide 2 ( 2(−) and 2(+) ) have been determined by X-ray methods. Crystals of 2 are orthorhombic, space group P2₁2₁2₁, Z = 4, with a = 5.1900(4) Å, b = 8.7960(7) Å, and c = 18.489(2) Å in 2(−) and a = 5.1897(7) Å, b = 8.787(1) Å, and c = 18.520(2) Å in 2(+). Structures 2(−) and 2(+) were refined to R factors equal to 0.041 and 0.052, respectively. The absolute configuration at the sulfur atom in enantiomer 2(−) with [α]equation/tex2gif-stack-1.gif = −20° (MeOH) is R_s. (In 2(+) , where [α]equation/tex2gif-stack-2.gif equals + 20° (MeOH), the absolute configuration at S atom is S_s.) In compounds 2(−) and 2(+) , a strong intermolecular hydrogen bond O3 H3 … O1 occurs.     

The activation of tertiary amines by osmium cluster complexes: Further studies of the reaction of Os3(CO)10(NCMe)2 with triethylamine

The reactions of Os₃(CO)₁₂ and Os₃(CO)₁₀(NCMe)₂ with NEt₃ have been reinvestigated. Two new products, Os₃(CO)₁₀(μ-CH₂C(H)?NEt₂)(μ-H)) (2) and Os₃(CO)₁₀(syn-μ-η¹-CHCHNEt₂)(μ-H) (3) were obtained in low yields, 4% and 7%, in addition to the previously reported compound Os₃(CO)₁₀(anti-μ-η¹-CHCHNEt₂(μ-H) (1) (20% yield) when the reaction was conducted at 25°C using Os₃(CO)₁₀(NCMe)₂. Compounds 2 and 3 were characterized by IR, ¹H NMR and single-crystal X-ray diffraction analyses. Compound 2 contains a bridging methyl-metallated N-ethylimine ligand formed by the cleavage of one ethyl group from the NEt₃. Compound 3 is an isomer of 1 in which the bridging ligand has a syn conformation with respect to the cluster as compared with the anti conformation in 1. Compound 3 slowly isomerizes to 1. Compound 3 is de-carbonylated by exposure to UV radiation and is transformed to the new compound Os₃(CO)₉(μ₃-CC(H)?NEt₂)(μ-H)₂ (4) (58% yield) by an additional CH activation to form a triply bridging η¹-diethylaminovinylidene ligand. Compound 4 isomerizes to the compound Os₃(CO)₉(μ₃-HCCNEt₂)(μ-H)₂ (5) (70% yield) at 68°C. The latter contains a triply briding ynamine ligand which exhibits structural and reactivity features that are characteristic of a carbene ligand at the amine-substituted carbon atom. Crystal data: for 2, space group = P2₁/c, a = 9.236(2) Å, b = 12.469(2) Å, c = 18.107(3) Å, β = 104.67(1)°, Z = 4, 2518 reflections, R = 0.031; for 3, space group = P2₁/m, a = 7.644(1) Å, b = 12.706(2) Å, c = 11.912(2) Å, β = 108.02(1)°, Z = 2, 1295 reflections, R = 0.030; for 4, space group = P2₁/n, a = 10.233(2) Å, b = 14.834(4) Å, c = 14.538(2) Å, β = 99.88(2)°, Z = 4, 2403 reflections, R = 0.036.     

A Missing Structural Link in the Werner Series of Cobalt(III) Complexes: The Crystal Structure of Δ‐(–)589‐Tris(ethylenediamine)cobalt(III) Iodide Monohydrate

Alfred Werner's historic resolution of Δ/Λ‐[Co(en)₃]³⁺ (where en = ethylenediamine) provided conclusive evidence for octahedral geometry coordination compounds and the first example of chirality in an inorganic molecule. Herein, we report the historically significant structure and absolute configuration of Δ‐(–)₅₈₉‐tris(ethylenediamine) cobalt(III) iodide monohydrate, Δ‐[Co(en)₃]I₃ ( 1 ), the missing crystallographic piece in the series of [Co(en)₃]³⁺ complexes. Complex 1 crystallizes in an orthorhombic space group P2₁2₁2₁ with unit cell dimensions of a = 8.4016(10), b = 11.2573(13), c = 18.825(2) Å, V = 1780.4(4) ų, and Z = 4. The absolute configuration of the complex cation [Co(en)₃]³⁺ is Δ and the en ligands adopt a λλδ configuration.     

Crystal structure and stereochemistry of (PS*, 2S*, 3aS*)-hexahydro-2-(tert-butylvinylthiophosphinyl)-6,6- dimethylpyrrolo[1,2-b]isoxazole

The structure of the major product of the cycloaddition of 2,2-dimethyl-3,4-dihydro-2H-pyrrole N-oxide to tert-butyldivinylphosphine sulfide was analyzed by means of single-crystal X-ray diffraction technique. The analysis revealed two crystallographically independent molecules that differed in conformation of the fused five-membered heterocyclic rings. These rings were found to be two envelopes in one molecule and two half-chairs in the other. The studied compound was identified as an exo adduct of the expected erythro configuration and was found to favor a conformation in which the PS and ring C–O bonds were anti and the CC–PS moiety was in the s-cis array. C₁₄H₂₆NOPS, space group P¯1, a = 10.6004(7) Å, b = 12.3225(6) Å, c = 13.4404(7) Å, α = 104.073(4)°, β = 92.758(4)°, γ = 95.968(5)°, V = 1688.802(4) ų, Z = 4.     

Palladium(II) Complexes with the Mixed‐Donor Ligand CH3S‐(CH2)3‐PPh2 Crystal Structures of [PdCl2{CH3S‐(CH2)3‐PPh2}n](n = 1, 2)

The phosphorus‐sulfur ligand 1‐(methylthio)‐3‐(diphenylphosphino)‐propane (S‐P3) has been synthesized and characterized by ¹H NMR and ¹³C NMR. Reactions of S‐P3 with [PdCl₂(PhCN)₂] afforded the complexes [PdCl₂(S‐P3)] ( I ) and [PdCl₂(S‐P3)₂] ( II ), in which S‐P3 acts as a bidentate and monodentate ligand, respectively. Compound I crystallizes in monoclinic space group P2₁/n (No. 14) with cell dimensions: a = 8.589(3), b = 15.051(3), c = 17.100(3)Å, β = 102.91(2)°, V = 2154.7(9)ų, Z = 4. Likewise, compound II crystallizes in monoclinic space group P2₁/n (No. 14) with a = 9.993(5), b = 8.613(4), c = 18.721(5)Å, β = 90.18(3)°, V = 1611.3(12)ų, Z = 2. Compound II has a trans square planar configuration with only the P‐site of the ligand bonded to the palladium atom.     

Über die kristall- und molekülstruktur und die absolute konfiguration des (+)-14-epicorynolin-bromacetats

The crystal structure and absolute configuration of ( + )-14-epicorynoline bromoacetate have been elucidated by X-ray diffraction method. The title compound forms monoclinic needles of space group P2₁, with a = 10.056, b = 7.400, c = 13.959 Å, β = 94.09°, and two molecules in the unit cell. The structure was determined by the heavy-atom method and refined by the least-squares method to R =0.082 for 1195 reflections collected by counter diffractometer techniques. Using the anomalous dispersion effect of the bromine atom, the absolute configuration was also determined as 11S, 13R and 14S. The mode of B/C-ring connection is trans; the rings B and C form half-chair and twist-half-chair conformations, respectively. The dihedral angle between the A- and D-rings is 11°. The hydroxyl-group at C-ll is trans to the methyl-group at C-13. The methyl-group at N-5 has an axial orientation and a 1,3-diaxial relationship to the angular methyl-group at C-13, which causes an unusual short distance of 3.11 Å between these methyl-groups.     

Synthesis and characterization of a Cu(II) complex of 2-benzylmercapto-5-methyl-1,3,4-thiadiazole (C10H10N2S2)

A Cu(II) complex of 2-benzylmercapto-5-methyl-1,3,4-thiadiazole was synthesized and characterized. The crystal structure of the copper complex and the free ligand were determined by single-crystal X-ray diffraction at room temperature: {[Cu(C₁₀H₁₀N₂S₂)₂(Cl)₂], P 1 triclinic, a = 8.1450(2) Å, b = 8.1690(2) Å, c = 10.8180(3) Å, α = 97.4040(12)°, β = 101.6270(11)°, γ = 116.1431(14)°; C₁₀H₁₀N₂S₂ ligand, Pbca orthorhombic, a = 8.7938(7) Å, b = 9.6491(7) Å, c = 25.3552(18) Å}. The metal complex framework consists of discrete units that provide crystalline stability through a network of van der Waals contacts. The Cu(II) is coordinated by two chloride ions and two 2-benzylmercapto-5-methyl-1,3,4-thiadiazole monodentate ligands showing a distorted square planar configuration. Both thiadiazole ligands coordinate through the N atom bonded to the benzylthio substituted C atom.

The FTIR spectroscopic data are consistent with this structural model. Analysis of the magnetic susceptibility from 5 K to room temperature indicates the presence of paramagnetic Cu(II), confirmed by the EPR spectrum.     

Synthesis and Characterization of a Two‐Dimensional Zinc Phosphite,Zn3(tren)(HPO3)3·xH2O (x ≈ 0.5; tren = tris(2‐aminoethyl)amine)

A new zinc phosphite with the formula Zn₃(tren)(HPO₃)₃·xH₂O (x≈0.5) has been synthesized under hydrothermal conditions and characterized by FTIR, elemental analysis, powder X‐ray diffraction, single‐crystal X‐ray diffraction, thermogravimetric analysis and its fluorescent spectrum. The compound crystallizes in the triclinic system, space group (No.2), a = 10.1188(9) Å, b = 10.4194(9) Å, c = 10.5176(9) Å, α = 60.763(2)°, β = 70.6150(10)°, γ = 80.725(2)°, V = 912.77(14) ų, Z = 2. The structure consists of double crankshaft chains, which are linked by Zn‐O‐P bonds to form 8‐ and 12‐membered channels along the [100] direction. The claw‐like Zn‐centered complexes of Zn(N₄C₆H₁₈) as the supported templates, hang into the 12‐MR channels through Zn‐O‐P linkages with framework.     

Synthesis and polymerization of racemic and optically active substituted ß-propiolactones. V. α-methyl ß-propiolactone

R(+) and S(?) enantiomers of α-methyl β-propiolactone (MPL) have been synthesized from the corresponding α-methyl β-hydroxymethylpropionates and racemic MPL from methyl methacrylate. The optical purity and absolute configuration of these lactones were determined using ¹H-NMR spectroscopy after complexation with a chiral compound: 2,2,2-trifluoro-1-(9-anthryl)-ethanol. Optical purities of 100% were obtained for both the S(?) ([α₀] = ?10.4°, c = 1.3 g/dL in CHCl₃) and the R(+) ([α₀] = +10.5°, c = 1.0 g/dL in CHCl₃) enantiomers. The corresponding racemic and optically active polylactones [poly(MPL)] were prepared by anionic polymerization, in bulk and in solution, as well as poly(MPL)s of intermediate optical purities. The polymers thus obtained are optically active ([α₀] = 16.2° in CHCl₃ for the optically pure polymer, S configuration) and exhibit significant differences. For example, the racemic poly(MPL) is soluble in several organic solvents such as tetrahydrofuran, benzene, CCl₄, CH₂Cl₂, hexafluoroisopropanol, and CHCl₃, whereas the optically active poly(MPL)s are soluble in CHCl₃ and hexafluoroisopropanol only. Moreover, racemic poly(MPL) is amorphous whereas optically active poly(MPL)s are semicrystalline for optical purities larger than 51%. Melting temperatures and enthalpies of fusion of the semicrystalline polylactones vary with optical purity whereas glass transition temperatures remain invariant for all polymers, at about ?28°C. The poly(MPL) of highest optical purity exhibits a melting temperature of 95°C and an enthalpy of fusion of 61 J/g.     

The synthesis,structural characterization and biocidal properties of some triorganotin(IV) esters of N-arylidene-ω-amino acids.

The methods of synthesis, elemental analysis, IR and NMR spectroscopic data and fungicidal activity against Ceratocystis ulmi are reported for a series of triorganotin esters of N-arylidene-ω-amino acids of general formula R₃SnOCO(CH₂)_nN = CHAr (R = Ph, n-Bu; Ar = 2-HOC₆H₄, 2-HOC₁₀H₆; n = 1, 2, 3 and 5). The crystal structures for two of the compounds, tributyltin N-2-hydroxynaphthalidene glycinate ( 1 ) and tributyltin N-2-hydroxynaphthalidene-β-alaninate ( 2 ), have been determined. Although both of these compounds have a trans-R₃SnO₂ structure, in compound 1 the carboxylate group is monodentate and the fifth coordination position around the tin atom is taken up by a coordinated phenolic group, whereas in 2 the carboxylate group is bridging. These two examples thus correspond to the two different structures reported for trans-R₃SnO₂ complexes. Both compounds were found to be active against Ceratocystis ulmi, but there was no significant difference in their levels of biological activity against this particular fungus. Apart from compound 1 , the other tributyltin compounds reported are believed to adopt the carboxylate bridging mode shown by compound ( 2 ). Crystal data: for 1 , crystals monoclinic, space group P 2₁/ c , a = 12.9435(11) Å, b = 13.5769(10) Å, c = 15.7715(12) Å, β = 108.919(6)°, Z = 4, R _f = 0.046 and R _w = 0.058 for 1448 significant reflections; for 2 , crystals monoclinic, space group C 2/ c , a = 24.588(14) Å, b = 9.733(3) Å, c = 27.611(12) Å, β = 113.49(4)°, Z = 8, R _f = 0.053 and R _w = 0.069 for 3822 significant reflections. © 1998 John Wiley & Sons, Ltd.     

Synthesis and Characterization of the Rubidium Thiophosphate Rb6(PS5)(P2S10) and the Rubidium Silver Thiophosphates Rb2AgPS4, RbAg5(PS4)2 and Rb3Ag9(PS4)4

The metal thiophosphates Rb₂AgPS₄ ( 2 ), RbAg₅(PS₄)₂ ( 3 ), and Rb₃Ag₉(PS₄)₄ ( 4 ) were synthesized by stoichiometric reactions, whereas Rb₆(PS₅)(P₂S₁₀) ( 1 ) was prepared with excess amount of sulfur. The compounds crystallize as follows: 1 monoclinic, P2₁/c (no. 14), a = 17.0123(7) Å, b = 6.9102(2) Å, c = 23.179(1) Å, β = 94.399(4)°; 2 triclinic, P$\bar{1}$ (no. 2), a = 6.600(1) Å, b = 6.856(1) Å, c = 10.943(3) Å, α = 95.150(2)°, β = 107.338(2)°, γ = 111.383(2)°; 3 orthorhombic, Pbca (no. 61), a = 12.607(1) Å, b = 12.612(1) Å, c = 17.759(2) Å; 4 orthorhombic, Pbcm (no. 57), a = 6.3481(2) Å, b = 12.5782(4) Å, c = 35.975(1) Å. The crystal structures contain discrete units, chains, and 3D polyanionic frameworks composed of PS₄ tetrahedral units arranged and connected in different manner. Compounds 1 – 3 melt congruently, whereas incongruent melting behavior was observed for compound 4 . 1 – 4 are semiconductors with bandgaps between 2.3 and 2.6 eV and thermally stable up to 450 °C in an inert atmosphere.     

Synthese von (+)-(5S, 6S)-Azafrin-methylester; absolute Konfiguration von Aeginetinsäure and von weiteren vicinalen Apocarotin-diolen

Synthesis of (+)-(5S, 6S)-Azafrin Methyl Ester; Absolute Configuration of Aeginetic Acid and of Further Vicinal Apocarotenediols We describe the synthesis of a series of optically active vicinal apo-β-carotenediols. Thus, starting from (+)-(5S, 6S)-5,6-dihydroxy-5,6-dihydro-β-ionone ( 2 ) we have prepared the (Z/E)-isomeric (+)-C₁₅-esters 7 and 8 , the (+)-retinoic derivatives 14 , 15 , 18 , 19 and (+)-methyl azafrinate ( 22 ), the enantiomer of the naturally occur-ring compound (s. Scheme 1). Our synthesis also establishes the absolute configura-tion of aeginetic acid ( 24 ), aeginetoside ( 25 ) and aeginetin ( 26 ), compounds isolated from the root parasite Aeginetia indica by Indian and Japanese workers (s. Scheme 2). The presented synthesis of optically active methyl azafrinate confirms our previous assignment [14] of the absolute configuration of azafrin ( 1a ), which was based on degradative evidence.     

The x-ray structure analysis of 17-beta-bromoacetoxy-9-beta, 10-alpha-androst-4-en-3-on

The structure of 17β-bromacetoxy-9β, 10α-androst-4-en-3-one has been determined by three-dimensional X-ray crystallographic methods. The crystals of the restrosteroid belong to the orthorhombic space group P2₁2₁2₁ with four molecules per unit cell. The cell constants are a = 11.32 Å, b = 13.71 Å and c = 12.52 Å. The absolute configuration of the molecule has been determined by the anomalous dispersion method. Bond length, bond angles and distances of atoms from ‘best planes’ are given. Ring A represents a distorted half-chair, ring B and C a chair and ring D an envelope conformation. The molecule shows, contrary to normal 9α, 10β-steroids, a bent shape.     

The synthesis and crystal structure of α-perthionaphthoatopyridinecopper(I) dimer Cu2(α-C10H7CSS2)2(Py)2

The title compound has been synthesized by the reaction of α-dithionaphthoic acid with CuCl₂ in pyridine or by recrystallizing Cu₄(α-C₁₀H₇CSS₂)₄ ? 1/2CS₂ in a mixture of pyridine and alcohol. The structure of the title compound is determined by a single-crystal X-ray diffraction analysis. The crystal belongs to triclinic space group with unit cell parameters: a=7.085(2)Å, b= 8.672(3)Å and c=13.598(5)Å; a=92.40(3)°, β=102.59(4)° and γ=105.67(4)°; V=780.6Ų; Z=1. The structure was refined to R=0.058 for 2390 reflections. The molecule of the title compound sits on a center of symmetry. The shorter Cu—Cu bond length (2.606Å) shows considerable interaction between copper atoms. If the Cu—Cu interaction is ignored, the neighbouring S and N atoms are coordinated to copper atom in a configuration of distorted tetrahedron.     

Synthesis and study of a new kind of lead complex with variable coordination numbers

The crystal C₁₈H₁₂O₁₀Pb₃ is synthesized by Pb and phenyl propylene acid. The crystal is characterized by IR and single-crystal X-ray diffraction. The crystal belongs to monoclinic system, space group P2₁/c with the crystal cell parameters of a = 15.3263(14) Å, b = 16.3479(14) Å, c = 8.1006(7) Å, β = 92.3060(10)°, V = 2028.0(3) ų, and Z = 4. Through the molecular structure of complex, we can see that Pb has three kinds of coordination modes (5, 6, 7). The compound has formed a 1D surface shape structure through these coordinate modes with the ligand, and this 2D layer piles through C-H…π forms the 3D compound.