[3]Parycyclo− and [3]metacyclo[3](3,7)-p-tropoquinonophanes

The title phanes were synthesized. Examination of their physical properties including X-ray crystallography disclosed that 1) the p-tropoquinone ring is still bent in both compounds though to a lesser extent than in the corresponding [2.2]phanes, 2) the metacyclo compound prefers syn conformation in solution, and 3) the intramolecular CT interaction is very similar in two compounds.     

Phosphine-catalyzed annulations of azomethine imines: allene-dependent [3 + 2], [3 + 3], [4 + 3], and [3 + 2 + 3] pathways

In this paper we describe the phosphine-catalyzed [3 + 2], [3 + 3], [4 + 3], and [3 + 2 + 3] annulations of azomethine imines and allenoates. These processes mark the first use of azomethine imines in nucleophilic phosphine catalysis, producing dinitrogen-fused heterocycles, including tetrahydropyrazolo-pyrazolones, -pyridazinones, -diazepinones, and -diazocinones. Counting the two different reaction modes in the [3 + 3] cyclizations, there are five distinct reaction pathways-the choice of which depends on the structure and chemical properties of the allenoate. All reactions are operationally simple and proceed smoothly under mild reaction conditions, affording a broad range of 1,2-dinitrogen-containing heterocycles in moderate to excellent yields. A zwitterionic intermediate formed from a phosphine and two molecules of ethyl 2,3-butadienoate acted as a 1,5-dipole in the annulations of azomethine imines, leading to the [3 + 2 + 3] tetrahydropyrazolo-diazocinone products. The incorporation of two molecules of an allenoate into an eight-membered-ring product represents a new application of this versatile class of molecules in nucleophilic phosphine catalysis. The salient features of this protocol--the facile access to a diverse range of nitrogen-containing heterocycles and the simple preparation of azomethine imine substrates--suggest that it might find extensive applications in heterocycle synthesis.     

Tetraazadibora[3, 3]paracyclophane

Starting from the para‐phenylenediamine derivative HN(SiMe₃)‐C₆H₄‐NH(SiMe₃), a lithiation and subsequent borylation give [(MeO)₂B]N(SiMe₃)‐C₆H₄‐N(SiMe₃)[B(OMe)₂] ( 1 ), the hydridation of which yields Li₂[(H₃B)N(SiMe₃)‐C₆H₄‐N(SiMe₃)(BH₃)] ( 2 ). Applying ZrCl₄ upon 2 initiates a condensation to give the title compound [‐N(SiMe₃)‐p‐C₆H₄‐N(SiMe₃)‐BH‐]₂, a hetero[3, 3]paracyclophane with two N‐B‐N chains that connect the para‐phenylene units. The product 3 crystallizes in the orthorhombic space group P2₁2₁2₁.     

Die Kristallstrukturen von [Et3PNAsPh3]2[Ag2Br4] und [Et3PNAsPh3]2[Pd2Br6]

Crystal Structures of [Et₃PNAsPh₃]₂[Ag₂Br₄] and [Et₃PNAsPh₃]₂[Pd₂Br₆] Colourless single crystals of [Et₃PNAsPh₃]₂[Ag₂Br₄]( 1 ) and red single crystals of [Et₃PNAsPh₃]₂[Pd₂Br₆]( 2 ) have been isolated from saturated solutions in acetonitrile of equivalent mixtures of [Et₃PNAsPh₃]Br with AgBr and PdBr₂, respectively. Both complexes were characterized by IR spectroscopy and by crystal structure determinations. 1 : Space group P1¯, Z = 1, lattice dimensions at ‐70°C: a = 985.0(2), b = 1042.2(5), c = 1345.8(5) pm, α = 102.88(2)°, β = 105.73(2)°, γ = 94.94(2)°, R₁ = 0.0577. 2 : Space group P2₁/c, Z = 2, lattice dimension at ‐70°C: a = 1003.0(1), b = 1371.8(2), c = 1974.0(1) pm, β = 93.30(1)°, R₁ = 0.0458. The dimeric anions of 1 and 2 form planar, centrosymmetric complex units.     

Reactions of [CH3]+ and [CD3]+ with alcohols

The reactions of [CH₃]⁺ and [CD₃]⁺ with a number of C₁ to C₅ alcohols were studied at approximately thermal energies (0.1 eV) using a tandem Dempster ion cyclotron resonance mass spectrometer. Branching ratios obtained under single collision conditions are reported for [CH₃]⁺ and [CD₃]⁺ with methanol, perdeutero methanol, ethanol, allyl alcohol, 1-propanol, 2-propanol, perdeutero-2-propanol, 1-butanol, 2-butanol, t-butanol, cyclopentanol and 1-pentanol. The results are examined in terms of the mechanism of reactions and indicate that upon progression to larger alcohols, the formation of a long-lived adduct becomes less important in determining the reaction products.     

Translational isomerism in a [3]catenane and a [3]rotaxane

[structure: see text] Post-assembly covalent modification using Wittig chemistry of [2]rotaxane ylides, wherein NH(2)(+) centers in the dumbbell-shaped components are recognized by dibenzo[24]crown-8 (DB24C8) rings, has afforded a [3]catenane and a [3]rotaxane with a precise and synthetically prescribed shortage of DB24C8 rings. The nondegenerate pairs of translational isomers present in both of these interlocked molecular compounds provide the fundamental platform on which to construct sensory devices and nanochemomechanical systems.     

Syntheses and characterization of oxygen/sulfur-bridged incomplete cubane-type clusters, [Mo3S4Tp3]+ and [Mo3OS3Tp3]+, and a mixed-metal cubane-type cluster, [Mo3FeS4ClTp3]. X-ray structures of [Mo3S4Tp3]Cl, [Mo3OS3Tp3]PF6, and [Mo3FeS4ClTp3

The reaction of [Mo3S4(H2O)9]4+ (1) with hydrotris(pyrazolyl)borate (Tp) ligands produced [Mo3S4Tp3]Cl x 4 H2O ([3]Cl x 4 H2O) in an excellent yield. An X-ray structure analysis of [3]Cl x 4 H2O revealed that each molybdenum atom bonded to the Tp ligand. We report four salts of 3, [3]Cl x 4 H2O, [3]tof x 2 H2O, [3]PF6 x H2O, and [3]BF4 x 2 H2O in this paper. The solubility and stability of the chloride salt in organic solvents differ completely from those of the other salts. We have also prepared a new compound, [Mo3OS3Tp3]PF6 x H2O ([4]PF6 x H2O), via the reaction of [Mo3OS3(H2O)9]4+ (2) with KTp in the presence of NH4PF6. All the molybdenum atoms bonded to Tp ligand. 1H NMR signals corresponding to nine protons bonded to three pyrazole rings in one Tp were observed in a spectrum (at 253 K) of [3]BF4 x 2 H2O. It shows that cluster 3 has a 3-fold rotation axis in CD2Cl2 solution. Twenty-one 1H NMR signals corresponding to twenty-seven protons bonded to nine pyrazole rings in three Tp ligands were observed in a spectrum (at 233 K) of [4]PF6 x H2O; obviously, 4 has no 3-fold rotation axis, in contrast to 3. The short CH...mu3S distance caused large upfield chemical shifts in the 1H NMR spectra of 3 and 4. The reaction of 3 with metallic iron in CH2Cl2 produced [Mo3FeS4XTp3] (X = Cl (5), Br (6)). X-ray structure analysis of 5 has revealed the existence of a cubane-type core Mo3FeS4. Complex 3 functions as a metal-complex ligand for preparing a novel mixed-metal complex even in nonaqueous solvents. The cyclic voltammogram of 5 shows two reversible one-electron couples (E(1/2) = -1.40 and 0.52 V vs SCE) and two irreversible one-electron oxidation processes (E(pc) = 1.54 and 1.66 V vs SCE).     

Hexaaryl[3]radialenes

Reactions of diarylmethyl anions whose conjugate acids are more acidic than diphenylmethane with tetrachlorocyclopropene are found to afford hexaaryl-[3]radialenes in modest to good yields, thus leading to the first synthesis of hexaphenyl[3]radialene itself too; X-ray crystalographic analysis of hexakis(p-cyanophenyl)[3]radialene reveals a double three-bladed conformation.     

Formal [3 + 2] and [3 + 3] additions of acceptor-substituted cyclopropylmethylsilanes to allenylsilanes

1,3-Dipolar synthons formed from vicinal TBDPS-substituted cyclopropyl alkyl/phenyl ketones on treatment with Lewis acids such as TiCl(4) and Et(2)AlCl reacted with allenylsilanes to furnish [3 + 2] and [3 + 3] adducts with high regio- and stereocontrol. [reaction: see text]     

Zwei Fluoridborate des Gadoliniums: Gd2F3[BO3] und Gd3F3[BO3]2

Two Fluoride Borates of Gadolinium: Gd₂F₃[BO₃] and Gd₃F₃[BO₃]₂ By flux‐supported solid‐state reaction of Gd₂O₃ and GdF₃ with B₂O₃ (flux: CsCl, molar ratio: 1 : 1 : 1 : 6, sealed tantalum capsule, 700 °C, 7 d) the new gadolinium fluoride borate Gd₂F₃[BO₃] (monoclinic, P2₁/c; a = 1637.2(1), b = 624.78(4), c = 838.04(6) pm, β = 93.341(8)°; V_m = 64.418(6) cm³/mol, Z = 8) was obtained as colourless, prismatic, face‐rich single crystals. The four crystallographically different Gd³⁺ cations (CN = 9) are all capped square‐antiprismatically surrounded by fluoride and oxide anions, in which the latter represent always components of isolated trigonal planar [BO₃]^3— anions. The six crystallographically independent F^— anions all reside in more or less planar coordination of three Gd³⁺ cations. Thus the constitution of Gd₂F₃[BO₃] can be described as a sequence of alternating layers each of the composition Gd[BO₃] and GdF₃ parallel (100), respectively. The crystal structures of Gd₂F₃[BO₃] and the shortly published Gd₃F₃[BO₃]₂ (monoclinic, C2/c; a = 1253.4(1), b = 623.7(1), c = 836.0(1) pm, β = 97.404(6)°; V_m = 97.571(9) cm³/mol, Z = 4) are compared with each other. Due to the structural analogies between these two gadolinium fluoride borates, a disorder model of the boron atoms frequently found for Gd₂F₃[BO₃] is able to be transferred to Gd₃F₃[BO₃]₂ as well.     

PPh4[As3S3Cl4] und PPh4[As3S3Br4]

PPh₄[As₃S₃Cl₄] and PPh₄[As₃S₃Br₄] When As₂S₃ reacts with PPh₄X and HX in 1,2-C₂H₄X₂ (X = Cl, Br), the title compounds are obtained as minor products; the main products are PPh₄[As₂SX₅]. Their crystal structures were determined by X-ray diffraction. PPh₄[As₃S₃Cl₄]: a = 1187.7, b = 1090.9, c = 1191.8 pm, α = 82.91, β = 88,93, γ = 88.52°; twins with twin plane (100); R = 0.109 for 1618 observed reflexions of one twin crystal. PPh₄[As₃S₃Br₄]: a = 1119.7, b = 1177.5, c = 1204.1 pm, α = 81.59, β = 85.88, γ = 88.25°; R = 0.061 for 2331 observed reflexions. Both compounds crystallize in the space group P1 , Z = 2, and can be considered to be isotypic. Nevertheless, PPh₄[As₃S₃Br₄] does not form twins as PPh₄[As₃S₃Cl₄]. The crystals consist of PPh₄⁺ and [As₃S₃X₄]^? ions. In the anions, the three As atoms of an As₃S₃ ring in the chair conformation are commonly joined to an X atom and each As atom is bonded to one further terminal X atom. Cations and anions are packed in alternating layers.     

SYNTHESIS AND STRUCTURE OF[Et_4N]_3[FE_3(SPh)_3Br_3Cl_3]

<正> The title compound was synthesized and its structure solved. The formula is [Et4N]3[Fe3(SPh)3Br3Cl3]. M=1231.95, monoclinic, space group C2/c, a=24.569(4), b=13.504(2), c=18.348.(3)A, β=110.78(1)°, V=5691(3)A3, Z=4, Dm= 1.41, Dc=1.44-g/cm3. The flat structure of the anion has. a planar [Fe3S3] ring and three phenyl groups. Statistical distribution of chlorine and bromine atoms on two sides of the [Fe3S3] plane results in a C2 symmetry of the anion.     

Über K2PbO3 [1,2] Rb2PbO3 [3–5] und Cs2PbO3 [6,7]

On the Oxides A₂PbO₃ (A = K, Rb, Cs) The oxides A₂PbO₃ (A = K, Rb, Cs) have been reinvestigated [four-circle diffractometer PW 1100 (Fa. Philips), all particles ?anisotropically”? refined, parameters see text]. The structural features are confirmed, whereas the results on space group and parameters have to be partially corrected.     

Phosphaniminato-Komplexe von Niob und Tantal. Die Kristallstrukturen von [NbCl4(NPiPr3)(CH3CN)], [NbCl3(NPiPr3)2], [TaCl4(NPiPr3)]2 und [TaCl3(NPiPr3)2]

Phosphorane Iminato Complexes of Niobium and Tantalum. Crystal Structures of [NbCl₄(NPⁱPr₃)(CH₃CN)], [NbCl₃(NPⁱPr₃)₂], [TaCl₄(NPⁱPr₃)]₂, and [TaCl₃(NPⁱPr₃)₂] The title compounds have been prepared from the pentachlorides of niobium and tantalum with the silylated phosphorane imine Me₃SiNPⁱPr₃. They are characterized by IR spectroscopy and crystal structure determinations. NbCl₄(NPⁱPr₃)(CH₃CN)] . Space group Pna2₁, Z = 4, 2102 observed unique reflections, R = 0.022. Lattice dimensions at ?50°C: a = 1627.2, b = 876.3, c = 1335.3 pm. The compound forms monomeric molecules with the acetonitrile molecule in trans position to the phosphorane iminato group. This group shows a short NbN distance of 178.2 pm with a NbNP bond angle of 165.2°. [NbCl₃(NPⁱPr₃)₂] . Space group Cc, Z = 4, 2534 observed unique reflections, R = 0.046. Lattice dimensions at 20°C: a = 1302.65, b = 1321.69, c = 1672.04 pm, β = 111.713°. The compound forms monomeric molecules with a distorted bipyramidal surrounding of the niobium atom and equatorially arranged phosphorane iminato groups. [TaCl₄(NPⁱPr₃)]₂ . Space group Pbca, Z = 4, 1537 observed unique reflections, R = 0.037. Lattice dimensions at ?40°C: a = 1420.6, b = 1483.9, c = 1622.0 pm. The compound forms centrosymmetric dimeric molecules with dissimilarly long Ta₂Cl₂ bridges and equatorially arranged phosphorane iminato groups. [TaCl₃(NPⁱPr₃)₂] . Space group Cc, Z = 4, 5737 observed unique reflections, R = 0.039. Lattice dimensions at ?50°C: a = 1303.9, b = 1327.2, c = 1682.1 pm, β = 111,92°. The compound is isotypical with the corresponding niobium compound.