Crystal structures of bis-11-aminoundecanoic chlorocuprate and bis-11-aminoundecanoic-Cu(II) sulfate trihydrate

Bis-11-aminoundecanoic chlorocuprate: (I),M _r =609.5, triclinic,P¯1 (No. 2),a=7.237(1),b=7.536(1),c=27.605(2) Å, =97.98(8),=92.45(8), =90.02(8)°,V _c =1492 ų,Z=2,D _x =1.357 g cm^–3,D _m =1.35(1) g cm^–3 (flotation), =43.85 cm^–1, CuK radiation=1.5418 Å,F(000)=642,T=23 °C,R=0.065 for 4121 observed reflections. Bis-11-aminoun-decanoic sulfate Cu(II) trihydrate: (II),M _r =616.4, triclinic,P¯1,a=7.745(2),b=9.553(4),c=20.343(5) Å, =80.91(3),=79.28(2), =87.58(3)°,V _c =1460 ų,Z=2,D _x =1.40(1) g cm^–3,D _m =1.38(2) g cm^–3 (flotation),=8.16 cm^–1, MoK radiation=0.71069 Å,F(000)=658,T=23°C,R=0.064 for 3384 observed reflections. In (I) the two copper ions are in special positions 0, 0, 0 and 1/2, 1/2, 0 octahedrally coordinated to Cl^–. The CuCl ₂ ^2– ions make square planes with the short bonds of mean values 2.289 and 2.295 Å. The carbonyls are hydrogen bonded, and the conformation of the amino acid chains ist for whole chain except at C(11) of chainA and N of chainB where it isg. In (II) Cu²⁺ shows a very distorted octahedral coordination with a mean value of 1.959 Å for the short bonds Cu-O and 2.512 Å for the long bonds. TheB amino acid chain presents a similar conformation change at C(11) as in theA chain of complex (I).     

Single crystal X-ray structure of 11-acetoxy-4-deoxyasbestinin B

The crystal structure of 11-acetoxy-4-deoxyasbestinin B (C₂₂H₃₄O₄,M _r=362.49) crystallized in the orthorhombic space groupP2₁2₁2₁ witha=10.923(5)Å,b=11.127(5)Å,c=17.047(5)Å,V=2072(3)ų,Z=4,D _x=1.163g/cm^–3. MoK radiation was used for data collection at room temperature. The finalR=0.042 for 2464 observed reflections. The stereochemical assignments of the molecule from the 2-D NMR data are verified totally by the overall geometry of the molecule obtained from the X-ray diffraction analysis.     

The structure of Dimethylaminomethanediphosphonic Acid,C3H11NO6P2

M_r = 218.9, monoclinic, P 2₁/c, a = 6.870(1), b = 10.824(2), c = 11.337(2) Å, β = = 94.59(2)⁰, Z = 4, V = 840.5(3) ų, D_x = 1.73 Mgm⁻³. Final R = 0.033 for 2648 independent reflections, excluding those with |F₀| < 3σ(F₀). Intensities were measured with an automatic diffractometer. This organophosphorous compound is characterized by two P C bonds. Four symmetrically independent intermolecular hydrogen bonds determine the threedimensional packing of the molecules and the unique chemical properties of the campound.     

Synthesis and crystal structure of 4,5-dibromo[2.1.1]triblattene

Reaction of 4-bromopentacyclo[7.3.0.0^2,7.0^3,11.0^6,10]dodec-11-ene (1) with Br₂—CCl₄ afforded 4,4,5-tribromopentacyclo[7.3.0.0^2,7.0^3,11.0^6,10]dodecane (2) in 89–94% yield. Subsequent treatment of 2 with KOt-Bu-t-BuOH resulted in competitive elimination of the elements of HBr and of Br₂ with concomitant formation of 4,5-dibromopentacyclo[7.3.0.0^2,7.0^3,11.0^6,10]dodec-11-ene (3, 76%) and 1 (17%), respectively. The structure of 3 was established unequivocally via application of X-ray crystallographic methods. Crystal data for 3: monoclinic, C2/c, a = 9.895(1), b = 9.0963(7), c = 12.471(1) Å, = 106.875(8)°, z = 4.     

Molecular and crystal structure of bis-quinolizidine immonium salts. IV. Δ1(6),11(16)-didehydro-sparteinium diperchlorate

^1(6),11(16)-Didehydrosparteinium diperchlorate,M _r =431.27, (C₁₅H₂₄N₂)²⁺ ·2C1O ₄ ^– , orthorhombic, C222₁,a=9.295(1),b=12.447(1),c=16.834(2) Å,V _c =1947.5(4) ų,Z=4,D _m =1.47 g cm^–3,D _c =1.47 g cm^–3,(CuK)=31.7 cm^–1. The finalR=0.052 for 733 counter reflections. The dication and the perchlorate anions lie on two-fold axes, and one perchlorate anion is disordered in two symmetrically equivalent positions. The two independent rings of the dication have conformations intermediate between half-chair and sofa, and the quinolizidine moiety (AB system) has a planar configuration.The title compound was obtained by mercuric acetate dehydrogenation of sparteine to ^5,11-didehydrosparteine and protonation of the latter in methanol with perchloric acid.¹³C-NMR spectra in DMSO-²H₆ and in²H₂O revealed the presence of the symmetrical diimmonium structure of the salt in solution.     

Structural study of PbO-MoO3-P2O5 glasses by Raman and NMR spectroscopy

Glasses in the ternary system PbO-MoO₃-P₂O₅ were prepared in three compositional series (100 − x)[0.5PbO-0.5P₂O₅]-xMoO₃ (A), 50PbO-yMoO₃-(50 − y)P₂O₅ (B) and (50 − z)PbO-xMoO₃-50P₂O₅ (C) and their structure was studied by Raman and ³¹P NMR spectroscopies. In the compositional series (100 − x)[0.5PbO-0.5P₂O₅]-xMoO₃ homogeneous glasses were prepared in the concentration region of 0-70 mol% MoO₃. Their glass transition temperature increases with increasing MoO₃ content having a maximum at x = 50 mol% MoO₃. ³¹P MAS NMR spectra reveal that in the glass series (A) the incorporation of MoO₃ results in the shortening of phosphate chains and gradual transformation Q² units into Q² and Q⁰ units, prevailing in glasses with a high MoO₃ content. Octahedral structural units MoO₆ dominate in most glass compositions and they are present also in the structure of Pb(MoO₂)₂(PO₄)₂ compound corresponding to the glass composition 50Pb(PO₃)₂-50MoO₃. The analysis of Raman spectra of glasses of the (B) series with a high MoO₃ content showed the transformation of octahedral MoO₆ units into tetrahedral MoO₄ units.     

Thermodynamic mixing properties of liquids in the system Na2O-SiO2

Enthalpies of fusion have been measured by differential scanning calorimetry for a Na₂O-SiO₂ system at 50, 66.6, and 74.4 mol% SiO₂. Enthalpies of mixing of liquids obtained from different calorimetry techniques are critically evaluated. The data on calorimetric enthalpy, activity of Na₂O, cristobalite liquidus, and immiscibility gap are used to determine the enthalpy and entropy of mixing of sodium-silicate liquids are determined as a function of composition by the least squares method. The derived mixing properties are based only on the experimental data and are independent of any assumption about the structure and chemical species in liquids. The enthalpy of mixing has a minimum value of −120 kJ/mol at 35-40 mol% SiO₂ and is convex upward around 80-90 mol% SiO₂. The entropy of mixing have a maximum value of + 6 J/K-mol at 75 mol% SiO₂, and it decreases with the SiO₂ content to −5 J/K-mol at 40 mol% SiO₂. This decrease in entropy can be accounted for by ideal mixing of Q⁴, Q³, and Q^{0 + 1 + 2} (= Q⁰ + Q¹ + Q²) species in the liquids and is responsible for the negative temperature dependence of the partial molar Gibbs energy of mixing of Na₂O, observed in activity measurements. Comparison of the present results with previous values suggests that a quasi-chemical model and the Adam-Gibbs model overestimate the configurational entropy of mixing of liquids.     

Structure of potassium germanophosphate glasses by X-ray and neutron diffraction: 2. Medium-range order

Characteristics of the medium-range order (MRO) of K₂O-GeO₂-P₂O₅ (KGP) glasses are obtained from X-ray and neutron scattering data. The behavior of the MRO is expressed in changes of pre-peaks and smooth contributions in the structure factors, S(Q), for Q < 12 nm^-1. Peaks at Q = (7.5 ± 0.5) nm^-1 (Q - magnitude of the scattering vector) are the outstanding features and reach maximum intensity for a glass of ∼25/50/25 mol% K₂O/GeO₂/P₂O₅. The pre-peaks are explained by a structural model in which K-rich and Ge-rich regions are separated by PO₄ units. The distance of repetition of similar regions (∼1 nm) is responsible for the pre-peak at ∼7.5 nm^-1. The intensity of this pre-peak is reduced and finally eliminated for glass compositions approaching the binary GeO₂-P₂O₅ system. The pre-peak is changed to a smooth scattering contribution and finally shifted to ∼9 nm^-1 for glass compositions approaching the binary K₂O-GeO₂ system. The strong tendency of the PO₄ units to coordinate K⁺ and Ge neighbors at their four corners is the source for the special MRO of the KGP glasses.     

Floating-zone growth of large high-quality CoAl2O4 single crystals

We report the first successful floating-zone growth of high-quality CoAl₂O₄ single crystals with volume up to 1 cm³ free from inclusions and sub-grains. The neutron rocking curves of the CoAl₂O₄ crystal have the width of about 0.30 degree proving the excellent quality of the grown samples. X-ray synchrotron experiments show that crystals have spinel structure with the lattice constant a₀=8.09853(1) Å. Magnetization measurements give the effective magnetic moment μ_eff=4.63 μ_B per Co⁺² ion in a good agreement with previous measurements on ceramic samples.     

Absolute structure of (11E, 1S, 3S, 4R, 7S, 8R, 14S)-3,7-diiodo-4,8-epoxy-euniolide

3,7-Diiodo-4,8-epoxy-euniolide (2) was synthesized from euniolide (1) by the addition reaction of iodine in the presence of triphenylphosphine in CH₂Cl₂. The absolute structure of 2 was unambiguously determined by a combination of ¹H and ¹³C NMR, HREI mass spectroscopy, and x-ray single crystal analysis as (11E, 1S, 3S, 4R, 7S, 8R, 14S)-3,7-diiodo-4,8-epoxy-cembra-11,15-dien-16,14-olide. X-ray crystallographic data for 2: Orthorhombic P2₁2₁2₁ (#19), a = 10.9688(7), b = 11.3909(8), c = 16.885(1) Å, _calcd = 1.795 g cm^–3, and for Z = 4.     

Development of porous silicon matrix and characteristics of porous silicon/tin oxide structures

Porous silicon (PSi) was formed at different current densities in the range of 5-60 mA/cm² by electrochemical anodized etching in HF for different durations in the range of 10-30 min. Above this PSi structure, SnO₂ films were deposited by the spin coating technique. The PSi has been characterized by X-ray diffraction studies. Peaks pertaining to PSi along with those corresponding to SnO₂ are observed. Atomic force microscopic studies indicate that very fine needle like silicon nanostructures are observed which is the result of the best PSi structure formed at 30 mA/cm². For the SnO₂ covered PSi structures, larger grains are observed with uniform coverage. The PSi samples prepared at current densities above and below 30 mA/cm² show PL spectra with asymmetric and overlapped peaks. The PL profile of thin SnO₂ film coated on PSi shows a peak at 633 nm and a small hump at about 660 nm.     

Crystal and molecular structure of tricyclohexylphosphineethylidenenickel tricarbonyl: a reaction product of Ni(CO)4 and (C6H11)3P=(CH)CH3

The structure of tricyclohexylphosphineethylidenenickel tricarbonyl, (C₆H₁₁)₃P(CH)CH₃.Ni(CO)₃, has been determined by direct methods from 5858 automatic diffractometer data, and refined anisotropically to a finalR value of 0·094 (including hydrogen atoms). The crystals are monoclinic, space group P2₁/n, with a=10·670(1), b=13·879(2), c=16·222(2) Å, =91·80(1)° and z=4. The main feature of the structure determination is the confirmation of the predicted arrangement of the ligand with its bonding to nickel via the secondary carbon of ylid-ligand. This carbon and the nickel atoms show approximate tetrahedral geometry. There seems to be no direct interaction between phosphorus and nickel (closest approach distance is 3·30 Å). The nickel-carbon distance (2·10 Å) is longer than any other Ni-C(sp³) distance previously reported.No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission of Plenum Publishing Company Limited.National Lending Library Supplementary Publication No. 60056 contains 29 pages of structure factor tables on 1 microfiche.     

Effect of Al2O3 on the viscosity and structure of calcium silicate-based melts containing Na2O and CaF2

The effect of Al₂O₃ on viscosity in the calcium silicate melt-based system containing Na₂O and CaF₂ was investigated and correlated with the melt structure using FTIR (Fourier transform infrared) spectroscopy, XPS (X-ray photoelectron spectroscopy), and Raman spectroscopy. Substituting SiO₂ with Al₂O₃ modified the dominant silicate network into a highly structured alumino-silicate structure with the aluminate structure being particularly prevalent at 20 mass% of Al₂O₃ and higher. As the melts become increasingly polymerized with higher Al₂O₃ content, the fraction of symmetric Al–O⁰ stretching vibrations significantly increased and the viscosity increased. XPS showed a decrease in the amount of non-bridged oxygen (O^?) but an increase in bridged oxygen (O⁰) and free oxygen (O^2?) with higher Al₂O₃. Although changes in the structure and viscosity with higher CaO/(SiO₂ + Al₂O₃) were not significant, the symmetric Al–O⁰ stretching in the [AlO₄]^5?-tetrahedral units decreased. The apparent activation energy for viscous flow varied from 118 to 190 kJ/mol.     

Structure study of multi-component borosilicate glasses from high-Q neutron diffraction measurement and RMC modeling

A neutron diffraction structure study has been performed on multi-component borosilicate glasses with compositions (65 − x)SiO₂ · xB₂O₃ · 25Na₂O · 5BaO · 5ZrO₂, x = 5-15 mol%. The structure factor has been measured up to a rather high momentum transfer value of 30 Å⁻¹, which made high r-space resolution available for real space analyses. Reverse Monte Carlo simulation was applied to calculate the partial atomic pair correlation functions, nearest neighbor atomic distances and coordination number distributions. The Si-O network consists of tetrahedral SiO₄ units with characteristic first neighbor distances at r_Si-O = 1.60 Å and r_Si-Si = 3.0 Å. The boron environment contains two well-resolved B-O distances at 1.40 and 1.60 Å and both 3- and 4-fold coordinated B atoms are present. A chemically mixed network structure is proposed including ^[4]B-O-^[4]Si and ^[3]B-O-^[4]Si chain segments. The O-O and Na-O distributions suggest partial segregation of silicon and boron rich regions. The highly effective ability of Zr to stabilize glassy and hydrolytic properties of sodium-borosilicate materials is interpreted by the network-forming role of Zr ions.     

Crystal growth of KInO2 from a hydroxide flux

Single crystals of KInO₂ were obtained from a reactive potassium hydroxide flux at 700 °C. KInO₂ crystallizes in the R-3m crystal system with a=3.2998(10) Å, c=18.322(10) Å and V=172.78(12) Å³. The crystal structure is isotypic with that of α-NaFeO₂ and consists of the (1 1 1) layers being occupied alternately by KO₆ and InO₆ octahedra. Three different AInO₂ structure types are discussed.     

Interpretation of some13C-11B spin-spin couplings using finite perturbation methods

Calculations are performed on a series of organoboranes by means of finite perturbation methods, using molecular wave functions obtained from INDOSCF approximations. The three terms, contact, orbital, and dipolar, are considered for contributions toJ(¹³C-¹¹B). The scaled values for the three contributions are obtained by treating the products of the squares of thes-electron densitiesS _C ² (0)S _B ² (0) and of the average values of r ^–3 _C r ^–3_B as least-squares variables. The results are compared with the experimental couplings, and conclusions are drawn.     

Unusual Glassy Smectic-G Liquid Crystal: Heat Capacity of N-p-n-Pentyloxybenzylidene-p'-n-butylaniline between 11 and 393 K

Abstract

The heat capacities of the title compound (C₃H₁₁,O—C₆H₄,- CH=N—C₆H₄,—C₄H₉, abbreviation 5O ? 4) with a purity of 99.92 mole percent have been measured with an adiabatic-type calorimeter between 11 and 393 K. The transition temperature and the enthalpy and entropy of phase transition for stable crystal → S_G, S_G → N and N → isotropic liquid were T _c = 299.69 K/ΔH = 22.68 kJ mol^?1/ΔS = 75.70 JK^?1 mol^?1, 325.72/7.11/21.79 and 342.48/1.78/5.22, respectively. The crystal which melts at 285.5 K is a metastable modification. The S_A phase hitherto reported in between S_G and N does not exist. The glassy So state was realized by rapid cooling of the specimen from the So phase. The molar enthalpy of the glassy S_G state at 0 K was by (10.1±0.1) kJ mol^?1 higher than that of the stable crystalline state and the residual entropy of the glassy state was (9.40±0.83) JK^?1 mol^?1. The relaxational heat-capacity anomaly was observed from as low as 100 K and double glass transition phenomenon occurred around 200 K; a quite unusual phenomenon which has never been observed for the glassy states of nematic and cholesteric liquid crystals. The present results give a fair evidence that the unusual glass transition phenomenon previously found for the S_G state of 6O?4 (a homologous compound) is not exceptional at all but common to the smectic glasses; at least common to the glassy S_G states. Two possible origins responsible for the double glass transitions have been discussed.     

Synthesis and crystal structure of [(η5-C9H11)TiCl(μ-0)]4

The tetramer, prepared by passing Cl₂ gas into a solution of [(⁵-C₉H₁₁)₂-TiCl₂] in CCl₄, crystallizes in the tetragonal space groupP¯42₁ c (No. 114). The unit cell parameters area=b=15.704(7),c=7.776(4) Å, and _cal=1.52g cm^–1 forZ=2 (tetramers). Full-matrix least-squares refinement gave a finalR value of 0.032 for 554 observed reflections. The molecule lies on a crystallographic ¯4 site. Both independent Ti-O distances are equal, 1.802(5) and 1.809(5) Å, and the Ti-Cl length is 2.281(3) Å. The five Ti-C() distances show the expected variation associated with an indenyl moiety: 2.310(9) to 2.437(9) Å.     

The Crystal and Molecular Structure of tert‐Butoxycarbonyl ‐ α‐aminoisobutyryl ‐ isoleucyl ‐methylester

The crystal structure of the synthetic peptide Boc — Aib — Ile ‐ OMe (C₁₆ H₃ 0 N₂ O₅ ) has been determined from three‐dimensional X — ray diffraction data. The peptide crystallizes in triclinic space group P1 with a = 9.570(9), b = 10.261(7), c = 10.610(2) Å , α = 101.9(0), β = 91.7(0), γ = 98.6(0)° V = 1006.1(12) ų, Z = 2, D_calc = 1.09 Mg m^‐3. The structure was solved by direct methods and refined by full‐matrix least‐squares method to an R value of 0.072 (λ = 1.5418Å). The conformation of Aib residue in molecule A is αL and in molecule B is αR. The Ile residue in molecule A adopts folded conformation, while in molecule B it is in the extended region. The peptide units are trans and show significant deviations from planarity.     

Structure and properties of glasses in ZnO-P2O5-TeO2 system

Glasses in the ternary ZnO-P₂O₅-TeO₂ system were prepared and studied in two compositional series (100 − x)[0.5ZnO-0.5P₂O₅]-xTeO₂ (X-series) and 50ZnO-(50 − y)P₂O₅-yTeO₂ (Y-series) within the concentration range of x = 0-60 and y = 0-40 mol% TeO₂. Their structure was studied by Raman and ³¹P MAS NMR spectroscopies. The incorporation of TeO_x units into the structural network is associated with the depolymerisation of phosphate chain structure as revealed by both methods. At a high TeO₂ content isolated PO₄ tetrahedra are formed in the structure of glass series Y, while diphosphate O₃P-O-PO₃ groups are present in the structure of the glass series X. In the structure of glass series Y tellurium atoms form predominantly TeO₃ trigonal pyramids, whereas in the X glass series TeO₄ trigonal bipyramids prevail in the glass structure. The addition of TeO₂ to the parent zinc metaphosphate glass results in a decrease of glass transition temperature in both compositional series associated with the replacement of stronger P―O bonds by weaker Te―O bonds.