Synthesis,structures, and physicochemical properties of Sr<Subscript>2</Subscript>A<Superscript>II</Superscript>UO<Subscript>6</Subscript> (A<Superscript>II</Superscript> = Mg,Ca, Sr,Ba, Mn,Fe, Co,Ni, Zn,and Cd) compounds

Sr₂A^IIUO₆ (A^II = Mg, Ca, Sr, Ba, Mn, Fe, Co, Ni, Zn, and Cd) compounds were synthesized by high-temperature reactions in the solid phase. The crystal structure (space group P2₁/n) was refined by the Rietveld method for Sr₂MgUO₆, (Sr_0.5Ba_0.5)₂SrUO₄, and Sr₂CdUO₆, which were synthesized for the first time. IR spectral characteristics were studied. The standard enthalpies of formation of the compounds were determined by reaction calorimetry.     

cis,cis,cis‐Tetra­methyl 1,2,4,5‐cyclo­hexane­tetra­carboxyl­ate

The title compound, C₁₄H₂₀O₈, was synthesized from the hydrogenation of tetra­methyl 1,4‐cyclo­hexa­diene‐1,2,4,5‐tetra­carboxyl­ate with a catalytic amount of palladium/carbon. All four carbonyl moieties of the methyl ester groups are on the same face of the chair‐conformed ring. The substantial ring distortion associated with the 1,3‐diaxial methoxycarbonyl substituents is reflected in the large difference between bond angles as well as torsion angles, respectively, that in undistorted cyclo­hexanes would be approximately the same.     

B,B, B-Trimethyl-N,N, N-triäthylborazin- und B,B, B-Triäthyl-N,N, N-trimethylborazin-molybdäntricarbonyl

The title compounds have been prepared in low yields starting with cis-(CH₃CN)₃-Mo(CO)₃ or Mo(CO)₆ (photochemical route). The new complexes are generally less stable than the corresponding hexaalkylborazine-chromium compounds and react very smoothly with Lewis bases by cleavage of the borazine-metal bond. The IR.-spectra indicate the similarity of type of bonding in hexaalkylborazine-molybdenum and -chromium complexes.     

Synthesis and characterization of polyamides containing octadecanedioic acid: Nylon‐2,18, nylon‐3,18, nylon‐4,18, nylon‐6,18, nylon‐8,18, nylon‐9,18, and nylon‐12,18

High‐aliphatic‐content linear nylons were produced with an 18‐carbon diacid with diamines containing both odd and even methylene segments. The resulting polymers were characterized with viscosimetric, thermal, and spectroscopic techniques. Solid‐state ¹⁵N NMR was used to determine the nylon crystalline form present. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 936–945, 2005     

N,N,N′,N′‐Tetra­methyl­ethyl­enedi­ammonium dichloride

The structure of the title compound, C₆H₁₈N₂²⁺.2Cl^?, has been determined and has a centre of symmetry. The mol­ecule has strong intermolecular hydrogen bonding between each Cl^? and an N—H bond [Cl?N = 3.012 (3) Å].     

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.     

Synthèse, à partir du (+) — camphre,d'hétérocycles dérives des tétrahydroxanthone,tétrahydroacridone,tétrahydroacridine et octahydroacridine

Derivatives of acridine, acridone and xanthone were prepared from (+)-camphor, 3-Arylidene, 3-arylmehtyl or 3-aroylcamphors with an halogen in the ortho position and dibornanonylarylmethanes may be uased aas precursors. Ring closure may be induced by ammonia, armoatic amines or potassium hydroxide with or without a catalyst. Good yaields were obtained. In come casaes, the reaction goes with an aromatisation of the heterocyclic moiety.     

Theoretical Investigations on 4, 10‐Dinitro‐2, 6,8, 12‐tetraoxa‐4, 10‐diazatetracyclo[5.5.0.05, 903, 11]dodecane

Based on the full optimized molecular geometric structure at B3LYP/cc‐pvtz method, the newly designed compound 4, 10‐dinitro‐2, 6,8, 12‐tetraoxa‐4, 10‐diazatetracyclo[5.5.0.0^{5, 9}0^{3, 11}]dodecane (TEX) was investigated. Additionally, the IR spectrum, the thermal stability, and the detonation performance were predicted. The obtained crystal structure of TEX belongs to Pbca space group and lattice parameters are Z = 8, a = 8.614 Å, b = 12.877 Å, c = 26.065 Å, ρ = 2.015 g · cm^–3. Calculation results show that TEX has better detonation properties than HMX and is a high energy density compound with better stability.     

Zeise,Liebig, Jensen,Hückel,Dewar, and the Olefin π‐Complex Bonds

Zeise's salt, KPt(C₂H₄)Cl₃, was the first characterized organometallic compound; it was also the first olefin π‐complex. It was published in 1825–1830 in the middle of a fight between Dumas on the one hand and Berzelius and Liebig on the other, who defended the etherin (ethylene) and radical theories, respectively. Although Zeise's formulation as a compound containing ethylene was vindicated, the fight went on for many years. This was a time when the theories of organic chemistry were being developed, before any clear understanding of the nature of molecules, bonding, and structure. Zeise thought of the structure of his salt as a product of the addition of PtCl₂ to ethylene. Jensen assumed a central bonding to ethylene but needed theoretical assistance to explain it. His attempt to obtain such an explanation from Hückel failed, and it was Dewar who explained the nature of π‐complexes in molecular orbital terms in 1951.     

Silylhydrazine und dimere N,N′‐Dilithium‐N,N′‐bis(silyl)hydrazide – Synthesen,Reaktionen, Isomerisierungen

Silylhydrazines and Dimeric N,N′‐Dilithium‐N,N′‐bis(silyl)hydrazides – Syntheses, Reactions, Isomerisations Di‐tert.‐butylchlorosilane reacts with dilithiated hydrazine in a molar ratio to give the N,N′‐bis(silyl)hydrazine, [(Me₃C)₂SiHNH]₂, ( 5 ). Isomeric tris(silyl)hydrazines, N‐difluorophenylsilyl‐N′,N′‐bis(dimethylphenylsilyl)hydrazine ( 7 ) and N‐difluorophenylsilyl‐N,N′‐bis(dimethylphenylsilyl)hydrazine ( 8 ) are formed in the reaction of N‐lithium‐N′‐N′‐bis(dimethylphenylsilyl)hydrazide and F₃SiPh. Isomeric bis(silyl)hydrazines, (Me₃C)₂SiFNHNHSiMe₂Ph ( 9 ) and (Me₃C)₂‐ SiF(PhMe₂Si)N–NH₂ ( 10 ) are the result of the reaction of di‐tert.‐butylfluorosilylhydrazine and ClSiMe₂Ph in the presence of Et₃N. Quantum chemical calculations for model compounds demonstrate the dyotropic course of the rearrangement. The monolithium derivative of 5 forms a N‐lithium‐N′,N′‐bis(silyl)hydrazide ( 11 ). The dilithium salts of 5 ( 13 ) and of the bis(tert.‐butyldiphenylsilyl)hydrazine ( 12 ) crystallize as dimers with formation of a central Li₄N₄ unit. The formation of 12 from 11 occurs via a N′ → N‐silyl group migration. Results of crystal structure analyses are reported.     

cis,cis,cis‐1,2,4,5‐Cyclo­hexane­tetra­carboxyl­ic acid and its dianhydride

cis,cis,cis‐1,2,4,5‐Cyclo­hexane­tetra­carboxyl­ic acid, C₁₀H₁₂O₈, (I), contains a mirror plane and the cyclo­hexane ring exhibits a chair conformation. Two crystallographically independent hydrogen bonds form (14), (16) and (16) ring motifs, and propagation of these two hydrogen bonds along the c and b axes generates (16) and (7) chains. cis,cis,cis‐1,2:4,5‐Cyclo­hexane­tetra­carboxyl­ic dianhydride, C₁₀H₈O₆, (II), was prepared by the reaction of (I) with acetic anhydride. The cyclo­hexane ring of (II) exhibits a boat conformation and the dihedral angle between the two an­hydro rings is 117.5 (1)°.     

Rare Earth-Rich Indides <Emphasis Type="Italic">RE</Emphasis><Subscript>5</Subscript>Pt<Subscript>2</Subscript>In<Subscript>4</Subscript> (<Emphasis Type="Italic">RE</Emphasis> = Sc,Y, La–Nd,Sm, Gd–Tm,Lu)

Summary. The isotypic indides RE ₅Pt₂In₄ (RE = Sc, Y, La–Nd, Sm, Gd–Tm, Lu) were synthesized by arc-melting of the elements and subsequent annealing. They were investigated via X-ray powder diffraction. Small single crystals of Gd₅Pt₂In₄ were grown via slow cooling and the structure was refined from X-ray single crystal diffractometer data: Pbam, a = 1819.2(9), b = 803.2(3), c = 367.6(2) pm, wR ² = 0.089, 893 F ² values and 36 parameters. The structure is an intergrowth variant of distorted trigonal and square prismatic slabs of compositions GdPt and GdIn. Together the platinum and indium atoms build up one-dimensional [Pt₂In₄] networks (292–333 pm Pt–In and 328–368 pm In–In) in an AA stacking sequence along the c axis. The gadolinium atoms fill distorted square and pentagonal prismatic cages between these networks with strong bonding to the platinum atoms.     

(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.