(4aR,8aS,9aR,10aS)‐8a,9a‐Difluoro‐1,4,4a,5,8,8a,9,9a,10,10a‐decahydroanthracene‐4a,10a‐diol hemihydrate

The title compound, C₁₄H₁₈F₂O₂·0.5H₂O, a hemihydrate of a C_s‐symmetric unsaturated difluorodiol, crystallizes in the centrosymmetric space group P2/m (Z = 4). The asymmetric unit contains two crystallographically independent difluorodiol half‐molecules, occupying the mirror planes at (x, 0, z) and (x, , z), and half a molecule of water, lying on the twofold axis at (0, y, 0). Four difluorodiol molecules self‐assemble around each solvent water molecule via O—H...O hydrogen bonds in a near tetrahedral symmetry to generate a cylindrical column‐like architecture.     

Crystal Structures,Bonding and Electronic Structures of MM′As,a Series of New Ternary Arsenides (M = Zr,Hf; M′ = Fe,Co, Ni)

All six new arsenides were prepared by arc-melting of preheated mixtures of the monoarsenides MAs with the 3d metals Fe, Co, and Ni, respectively. The isostructural title compounds all form the Co₂Si structure type, in contrast to the corresponding phosphides with ZrNiP occurring in the Ni₂In type. The anomalous expansions of the unit cells from ZrCoAs to ZrNiAs (V = 178.5(3) ų versus V = 182.5(1) ų) and from HfCoAs to HfNiAs (V = 175.03(5) ų versus V = 177.0(1) ų) can be understood based on Extended Hückel calculations of the electronic structure of HfCoAs.     

Darstellung,Kristallstruktur und IR‐Spektren von BeSeO3 · H2O – Wasserstoffbrücken und Korrelation von IR‐ und Strukturdaten in den Monohydraten MSeO3 · H2O (M = Be,Ca, Mn,Co, Ni,Zn, Cd)

Preparation, Crystal Structure and IR Spectra of BeSeO₃ · H₂O – Hydrogen Bonds and Correlation of IR and Structure Data in the Monohydrates MSeO₃ · H₂O (M = Be, Ca, Mn, Co, Ni, Zn, Cd) BeSeO₃ · H₂O (oP32) has been obtained by treating amorphous BeSeO₃ · 4 H₂O precipitated from Be(HSeO₃)₂ solutions hydrothermally at 150 °C. The crystal structure (P2₁2₁2₁, a = 560.59(4), b = 755.25(5), c = 781.14(5) pm, Z = 4, D_X = 3.092 gcm^–3, R = 0.018 for the 2034 reflections with I > 2σ_I of the enantiomer investigated) contains BeO₃(H₂O) tetrahedra built up from three selenite and one water oxygen atoms. The BeO₃(H₂O) tetrahedra are 3 D‐connected via Se atoms of trigonal pyramidal SeO₃^2– ions. The Be–O distances are 161.8 to 164.4 pm. The Se–O bond lenghts (169.2–170.3 pm) and the O–Se–O bond angles (98.1–101.4°) are normal. The water molecules of crystallization form together with the SeO₃^2– ions screw‐like hydrogen bond systems along [100]. Despite the strong synergetic effect of the Be²⁺ ions, the hydrogen bonds (d(OH…O) = 267.4 and 276.4 pm, respectively; ν_OD of matrix isolated HDO molecules: 2244 and 2405 cm^–1, respectively) are normal compared to other neutral selenite hydrates. Together with the hitherto known monohydrates M^IISeO₃ · H₂O and other beryllium salt hydrates, the hydrogen bonds of BeSeO₃ · H₂O are discussed with regard to their geometry and IR spectroscopy.     

Rubidium‐ und Caesium‐Verbindungen mit dem Isopolyanion [Ta6O19]8– – Synthesen,Kristallstrukturen, thermische und schwingungsspektroskopische Untersuchungen der Oxotantalate A8[Ta6O19] · n H2O (A = Rb,Cs; n = 0, 4, 14)

Rubidium und Caesium Compounds with the Isopolyanion [Ta₆O₁₉]^8– – Synthesis, Crystal Structures, Thermogravimetric and Vibrational Spectrocopic Analysis of the Oxotantalates A₈[Ta₆O₁₉] · n H₂O (A = Rb, Cs; n = 0, 4, 14) The compounds A₈[Ta₆O₁₉] · n H₂O (A = Rb, Cs; n = 0, 4, 14) contain the isopoly anion [Ta₆O₁₉]^8–, which consists of six [TaO₆] octahedra connected via corners to form a large octahedron. They transform into each other by reversible hydratation/dehydratation processes, as shown from thermoanalytic measurements (TG/DSC), and show also structural similarities. Cs₈[Ta₆O₁₉] (tetragonal, I4/m, a = 985.9(1) pm, c = 1403.3(1) pm, Z = 2), the isotypic phases A₈[Ta₆O₁₉] · 14 H₂O (A = Rb/Cs; monoclinic, P2₁/n, a = 1031.30(6)/1055.4(1) pm, b = 1590.72(9)/1614.9(6) pm, c = 1150.43(6)/1171.4(1) pm, β = 100.060(1)/99.97(2)°, Z = 2) and Rb₈[Ta₆O₁₉] · 4 H₂O (monoclinic, C2/c, a = 1216.9(4) pm, b = 1459.2(5) pm, c = 1414.7(4) pm, β = 90.734(6)°, Z = 4) have been characterised on the basis of single crystal x‐ray data. Furthermore the RAMAN spectra allow a detailled comparison of the hexatantalate ions in the four compounds.     

Synthesis of (±)‐Kempa‐6,8‐dien‐3‐ol (=(2aRS,3SR,4aSR,7RS,7aSR,10bSR,10cSR)‐2,2a,3,4,4a,5,6,7,7a,8,10b,10c‐Dodecahydro‐2a,7,10,10c‐tetramethylnaphth[2,18‐cde]azulen‐3‐ol)

The synthesis of kempa‐6,8‐dien‐3β‐ol ( 4a ), as a synthetic leading model of the natural product 4b , was carried out starting from intermediate 12 , the synthetic route of which has been developed previously (Scheme 1). The conversion of 12 to the model compound 4a involved the elaboration of three structure modifications by three processes, Tasks A, B, and C (see Scheme 2). Task A was achieved by epoxy‐ring opening of 41 with Me₃SiCl (Scheme 9), and Task B being performed by oxidation at the 13‐position, followed by hydrogenation, and then epimerization (Schemes 4 and 5). The removal of the 2‐OH group from 12 (Task C) was achieved via 30b according to Scheme 6, whereby 30b was formed exclusively from 30a / 31a 1 : 1 (Scheme 7). In addition, some useful reactions from the synthetic viewpoint were developed during the course of the present experiments.     

6a,6b,12a,12b‐Tetra­hydro­cyclo­octa­[3,4]­cyclo­buta­[1,2][8]­annulene

The cis,syn,cis‐tricyclic [2+2]‐dimer of cyclo­octatetraene, C₁₆H₁₆, crystallizes in space group Pca2₁ with two mol­ecules in the asymmetric unit. An extensive network of weak C—H⋯π(Czdbnd;C) interactions between the two independent mol­ecules, A and B, as well as A⋯A and B⋯B interactions, are observed in the supramolecular assembly. The C—H groups point more towards one C atom than to the centre of the Czdbnd;C bond. Notable among the interactions are bifurcated (cyclo­butane)C—H⋯Czdbnd;C contacts that span transannularly the eight‐membered ring.     

Synthesis and Characterization of the Lewis Acid‐Base Complexes SbCl5 · LB (LB = ICN,BrCN, ClCN, 1/2(CN)2, NH2CN,Pyridine) – a Combined Theoretical and Experimental Investigation. The Crystal Structures of SbCl5 · NCCl and SbCl5 · NCCN · SbCl5

The Lewis acid‐base complexes SbCl₅ · LB (LB = ICN, BrCN, ClCN, ¹/₂(CN)₂, NH₂CN, pyridine) were prepared. The products formed were characterized by Raman and NMR spectroscopy. Density functional theory (B3LYP) was applied to calculate structural and vibrational data. Vibrational assignments of the normal modes for these Lewis acid‐base adducts was made on the basis of their Raman spectra in comparison with computational results. The stability of the complexes was investigated by calculating the bond dissociation enthalpy. SbCl₅ · NCCl and SbCl₅ · NCCN · SbCl₅ were characterized by X‐ray structural analysis. NBO analyses were performed on the crystallographic data.     

Binuclear CpV,Cp*V,and Cp*Ta Complexes containing Organochalcogenolato Bridges, μ‐ER (E = Sulfur,Selenium, Tellurium; R = Methyl,Phenyl, and Ferrocenyl)

Photolysis of the halfsandwich tetracarbonylmetal complexes CpV(CO)₄, Cp*V(CO)₄ and Cp*Ta(CO)₄ in solution in the presence of di(organyl)dichalcogenides E₂R₂ (E = S, Se, Te; R = Me, Ph, Fc) leads to diamagnetic doubly organochalcogenolato‐bridged compounds, [Cp⁽⁾M(CO)₂(μ‐ER)]₂. According to the X‐ray structure determinations carried out for [CpV(CO)₂(μ‐TeMe)]₂, [Cp*V(CO)₂(μ‐TePh)]₂ and [Cp*Ta(CO)₂(μ‐SPh)]₂, the molecular framework consists of a folded M₂(μ‐ER)₂ ring with the cyclopentadienyl ligands in cis‐configuration and the organyl substituents R in a syn‐equatorial arrangement, thus forming a bowl‐shaped molecule with the four terminal CO ligands protruding into the inner sphere. The M…M distances (in the range between 305 and 330 pm) are not considered to indicate direct bonding interactions. The vanadium complexes [Cp⁽⁾V(CO)₂(μ‐ER)]₂ are completely decarbonylated in the presence of an excess of E₂R₂ in boiling toluene, and in many cases the paramagnetic quadruply‐bridged products, [CpV(μ‐ER)₂]₂, can be isolated.     

Synthese,Struktur und Eigenschaften von [nacnac]MX3‐Verbindungen (M = Ge,Sn; X = Cl,Br, I)

Synthesis, Structure, and Properties of [nacnac]MX₃ Compounds (M = Ge, Sn; X = Cl, Br, I) Reactions of [nacnac]Li [(2,6‐ⁱPr₂C₆H₃)NC(Me)C(H)C(Me)N(2,6‐ⁱPr₂C₆H₃)]Li ( 1 ) with SnX₄ (X = Cl, Br, I) and GeCl₄ in Et₂O resulted in metallacyclic compounds with different structural moieties. In the [nacnac]SnX₃ compounds (X = Cl 2 , Br 3 , I 4 ) the tin atom is five coordinated and part of a six‐membered ring. The Sn–N‐bond length of 3 is 2.163(4) Å and 2.176(5) Å of 4 . The five coordinated germanium of the [nacnac]GeCl₃ compound 5 shows in addition to the three chlorine atoms further bonds to a carbon and to a nitrogen atom. In contrast to the known compounds with the [nacnac] ligand the afore mentioned reaction creates a carbon–metal‐bond (1.971(3) Å) forming a four‐membered ring. The Ge–N bond length (2.419(2) Å) indicates the formation of a weakly coordinating bond.     

Intermetallic Gold Compounds REAuMg (RE = Y,La–Nd,Sm, Eu,Gd–Yb)

New intermetallic rare earth compounds REAuMg (RE = Y, La–Nd, Sm, Eu, Gd–Yb) were synthesized by reaction of the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffraction both on powders and single crystals. Some structures were refined on the basis of single crystal data. The compounds with Y, La–Nd, Sm, and Gd–Tm adopt the ZrNiAl type structure with space group P62m: a = 770.8(2), c = 419.5(1) pm, wR2 = 0.0269, 261 F² values for PrAuMg, a = 750.9(2), c = 407.7(1) pm, wR2 = 0.0561, 649 F² values for HoAuMg with 15 variables for each refinement. Geometrical motifs in HoAuMg are two types of gold centered trigonal prisms: [Au1Mg₃Ho₆] and [Au2Mg₆Ho₃]. The gold and magnesium atoms form a three‐dimensional [AuMg] polyanion in which the holmium atoms fill distorted hexagonal channels. The magnesium positions show a small degree of magnesium/gold mixing resulting in the refined compositions PrAu_1.012(2)Mg_0.988(2) and HoAu_1.026(3)Mg_0.974(3). EuAuMg and YbAuMg contain divalent europium and ytterbium, respectively. Both compounds crystallize with the TiNiSi type structure, space group Pnma: a = 760.6(3), b = 448.8(2), c = 875.8(2) pm, wR2 = 0.0491, 702 F² values, 22 variables for EuAuMg, and a = 738.4(1), b = 436.2(1), c = 864.6(2) pm, wR2 = 0.0442, 451 F² values, and 20 variables for YbAuMg. The europium position shows a small degree of europium/magnesium mixing, and the magnesium site a slight magnesium/gold mixing leading to the refined composition Eu_0.962(3)Au_1.012(3)Mg_1.026(3). No mixed occupancies were found in YbAuMg where all sites are fully occupied. In these structures the europium(ytterbium) and magnesium atoms form zig‐zag chains of egde‐sharing trigonal prisms which are centered by the gold atoms. As is typical for TiNiSi type compounds, also in EuAuMg and YbAuMg a three‐dimensional [AuMg] polyanion occurs in which the europium(ytterbium) atoms are embedded. The degree of distortion of the two polyanions, however, is different.     

Synthesis of a polypseudorotaxane, polyrotaxane, and polycatenane using ‘click’ chemistry

The synthesis of a polypseudorotaxane, polyrotaxane, and polycatenane containing the electron-deficient cyclophane cyclobis(paraquat-p-phenylene) (CBPQT⁴⁺) subunit in the side chain is described. These interlocked supramolecular polymers have been prepared from an azide-functionalized polystyrene derivative and an acetylene-functionalized [2]rotaxane, [2]catenane and their parent tetracationic cyclophane via Cu(I)-catalyzed 1,3 dipolar cycloadditions (‘click chemistry’). The synthesis and characterization of the polymers and intermediates has been described using IR, ¹H NMR, UV spectroscopies, and voltammetry. We have shown that the CBPQT⁴⁺ unit of the side chain polystyrene derivative has the ability to reversibly undergo complexation with a complementary dialkoxynaphthalene derivative.     

Three‐component,negative‐type,alkaline‐developable,thermally stable,and photosensitive polymer based on poly(2,6‐dihydroxy‐1,5‐naphthalene), a crosslinker,and a photoacid generator

A negative working and chemically amplified photosensitive polymer has been developed, which is based on poly(2,6‐dihydroxy‐1,5‐naphthalene) (PDHN), the crosslinker 4,4′‐methylenebis[2,6‐bis(hydroxymethyl)]phenol, and the photoacid generator (5‐propylsulfonyloxyimino‐5H‐thiophen‐2‐ylidene)‐(2‐methylphenyl)acetonitrile. PDHN, with a number‐average molecular weight of 25,000, was prepared by the oxidative coupling polymerization of 2,6‐dihydroxynaphthalene with di‐μ‐hydroxo‐bis[(N,N,N′,N′‐tetramethylethylenediamine)copper(II)] chloride in 2‐methoxyethanol at room temperature. The resulting PDHN showed a 5% weight loss temperature of 440 °C in nitrogen and a low dielectric constant of 2.82. The resist showed a sensitivity of 8.3 mJ cm^?2 and a contrast of 11 when it was exposed to 436‐nm light, followed by postexposure baking at 100 °C for 5 min and development with a 2.38 wt % aqueous tetramethylammonium hydroxide solution at 25 °C. A fine negative image featuring 10‐μm line‐and‐space patterns was obtained on a film 3 μm thick exposed to 10 mJ cm^?2 of ultraviolet light at 436 nm in the contact‐printed mode. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2235–2240, 2004     

Visible‐Light‐Driven,Tunable, Photoelectrochemical Performance of a Series of Metal‐Chelate,Dye‐Organized,Crystalline, CdS Nanoclusters

CdS nanoclusters of four different sizes were integrated with ruthenium‐complex dyes. The cluster–dye crystalline composites, [Cd₄(SPh)₁₀][Ru(bpy)₃], [Cd₈S(SPh)₁₆][Ru(bpy)₃], [Cd₈S(SPh)₁₃?Cl?(CH₃OCS₂)₂][Ru(phen)₃], [Cd₁₇S₄(SPh)₂₈][Ru(bpy)₃], and [Cd₃₂S₁₄(SPh)₄₀][Ru(phen)₃]₂ (phen=1,10‐phenanthroline and bpy=bipyridine), show intense absorption in the visible‐light region. They also exhibit size‐dependent photocurrent responses under the illumination of visible light. The photocurrent increases with increased cluster size. The dyes also have significant influence on the photocurrent generation of the composite.     

9‐Phenyl‐3,4,4a,9a‐tetrahydrotri­ptycene and 9‐phenyl‐1,2,3,4,4a,9a‐hexa­hydro­triptycene

The structure of 9‐phenyl‐3,4,4a,9a‐tetra­hydro­triptycene, C₂₆H₂₂, (I), exhibits regiochemistry consistent with a stepwise mechanism for its formation from photo­cyclo­addition of 1,3‐cyclo­hexa­diene and 9‐phenyl­anthracene. Bond distances involving the bridgehead C atoms are similar in (I) and the hydrogenated derivative, 9‐phenyl‐1,2,3,4,4a,9a‐hexa­hydro­triptycene, C₂₆H₂₄, (II), with bonds to the quaternary‐C atoms exhibiting significant elongation [1.581 (2) Å in (I) and 1.585 (2) Å in (II)]. The molecular geometry precludes significant σ–π overlap between the phenyl groups and the interannular bonds in both compounds, indicating that the origin of the bond lengthening is steric in nature.     

Dynamic behavior of 3a,4,4a,8-tetrahydro-4,4,8,8-tetramethyl-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-stannaindacene

The stannotropic rearrangement in 3a,4,4a, 8-tetrahydro-4,4,8,8-tetramethyl-tert-butyl-4-stanna-symm-indacene was studied by dynamic NMR spectroscopy. Line-shape analysis of the spectra with the use of various possible schemes of chemical exchange gives similar calculated spectra. The decision between three possible exchange schemes was made based on line-shape analysis, general structural considerations, and quantum chemical calculations. A comparison with the precursor, in which the Bu^t group is absent, shows that the presence of this group has an ambiguous effect on the activation barriers of rearrangements. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2286–2290, October, 2005.     

On Bonding,Structure, and Stability of Ternary Hydrides A2MH2 (A = Li,Na; M = Pd,Pt)

Bonding, structure, and stability of solid A₂MH₂ with A = Li, Na; M = Pd, Pt were investigated with a relativistically corrected density-functional approach, which reliably describes the trends among these four compounds. In order to examine the influence of the ligands (A) and of the crystalline environment, calculations were also made for free A₂MH₂ molecules and MH₂^2– ions. The free MH₂^2– complex is held together by strong bonds between formally closed shell atomic units because of strong M-d,s hybridization. The M–H bonds are further stabilized by the alkali metal ion ligands and by the crystal surrounding. The crystal field expands the H–A distance and enhances the H–A polarity. Relativistic effects contribute to M–H bonding in the solid state. The experimentally determined bond lengths and their trends are in accordance with theory. Due to relativistic and lanthanide effects, the Pt–H bond length becomes nearly as short as the Pd–H one. The small Li ion causes a distortion of the Li₂PtH₂ crystal resulting in an even shorter Pt–H bond length. In the gas-phase, A₂PtH₂ is more stable against dissociation than A₂PdH₂. The stability of the solid compounds is strongly influenced by the cohesive energy of the metal M, and also by the nature of the alkali metal. The evaluated enthalpies of formation favor increasing stability of solid A₂MH₂ against disproportionation into M and AH from Pt to Pd and from Li to Na. This is in agreement with experimental findings. The assignment of the experimental vibrational excitations should be reconsidered.     

Verbindungen des Typs (F3C)2EE′R mit Pseudohalogen-Charakter (E = P,As; E′ = S,Se, Te)

Perfluoromethyl Element Ligands. XLI. [1] Compounds of the Type (F₃C)₂EE′R with Pseudohalide Character (E = P, As; E′ = S, Se, Te) Perfluoromethyl phosphorus and -arsenic compounds of the type (F₃C)₂EE′R (E = P, As; E′ = S, Se, Te; R = organic group) are prepared either by dismutation (metathesis) of E₂(CF₃)₄ with (RE′)₂ or by reaction of the iodine compounds (F₃C)₂EI with mercury(II) organosulfanides Hg(SR)₂ and characterized by spectroscopic (¹H, ¹⁹F, ³¹P-NMR; IR; MS) as well as analytical investigations (C, H).