Benzamidinium acetylsalicylate: crystal structure of the first salt with acetylsalicylate anion

The first crystal structure of a non-coordinating acetylsalicylate anion containing salt was determined by X-ray crystallography. Benzamidinium acetylsalicylate crystallizes in the triclinic space group $ P\bar{1} The first crystal structure of a non-coordinating acetylsalicylate anion containing salt was determined by X-ray crystallography. Benzamidinium acetylsalicylate crystallizes in the triclinic space group (a = 9.8885(5), b = 10.2769(5), c = 15.2656(7) ?, α = 87.219(4), β = 78.261(4) and γ = 72.589(4) Z = 4, V = 1449.17(12) ?³, R1 = 0.0346 and wR2 = 0.0697). The structure comprises pairs of hydrogen bonded benzamidinium cations and acetylsalicylate anions connected into infinite chains through further N–H···O hydrogen bonds.     

1,10-Phenanthrolinium hydrogensquarate monohydrate—A non-centrosymmetric structure from two non-chiral agents

Four different dimethyltin(IV) complexes of Schiff bases derived from 2-amino-3-hydroxypyridine and different substituted salicylaldehydes have been synthesized. The compounds, with the general formula [Me₂Sn(2-OArCHNC₅H₃NO)], where Ar = –C₆H₃(5-CH₃) [Me₂SnL¹], –C₆H₃(5-NO₂) [Me₂SnL²], –C₆H₂(3,5-Cl₂) [Me₂SnL³], and –C₆H₂(3,5-I₂) [Me₂SnL⁴], were characterized by IR, NMR (¹H and ¹³C), mass spectroscopy and elemental analysis. Me₂SnL³ was also characterized by X-ray diffraction analysis and shows a fivefold C₂NO₂ coordination with distorted square pyramidal geometry. H₃C–Sn–CH₃ angles in the complexes were calculated using Lockhart's equations with the ¹J(^117/119Sn–¹³C) and ²J(^117/119Sn–¹H) values (from the ¹H-NMR and ¹³C-NMR spectra). The in vitro antibacterial and antifungal activities of dimethyltin(IV) complexes were also investigated.     

Minimal Submanifolds

This paper provides a survey of both old and new results aboutminimal surfaces and submanifolds. 2000 Mathematics SubjectClassification 54C40, 14E20 (primary), 46E25, 20C20 (secondary).     

Chirped-pulse Fourier transform microwave spectroscopy of perfluoroiodoethane

The pure rotational spectrum of perfluoroiodoethane between 8.0 and 11.9 GHz has been measured on a search accelerated, correct intensity Fourier transform microwave (SACI-FTMW) spectrometer. The spectra is dense with 247 measured transitions in the given region. Only the anti conformer was observed for which rotational constants are reported. Nuclear electric quadrupole coupling constants due to the iodine-127 were determined and are reported. Also, two dipole forbidden/quadrupole allowed ΔJ=2 transitions were observed in the spectra. The observation of these transitions has been rationalized on the basis of near degeneracies between energy levels connected by χ_ab.     

Solid support synthesis of 14- and 17-membered macrocycles via the SNAr methodology

Efficient assembly of 14-membered macrocycles utilizing the S_NAr of fluorine in 3-fluoro-4-nitrobenzoic acid with the OH of 3-hydroxytyrosine on solid support is reported. The flexibility of this synthesis, as well as the excellent purity (>90%) of the final products are the distinctive characteristic of the resultant library.     

Sublattices of regular elements

Let L be an r-lattice, i.e., a modular multiplicative lattice that is compactly generated, principally generated, and has greatest element 1 compact. We consider certain subsets of L consisting of regular elements: there is a compact element with there is a principal element is a principal element with (0:X_{\alpha })=0\} . The first three subsets L_{f}, L_{sr}, and L_{r} are augmented filters on L, i.e., is a multiplicatively closed subset of $L$ with $A\in and $B\geq A$ with $B\in L$ implies $B\in and hence are sublattices of $L$ closed under multiplication. We first consider the more general situation of augmented filters on $L.$ These results are then applied to study the four previously defined subsets for $L$ an $r$-lattice or Noether lattice (i.e., an $r$-lattice with ACC). Finally, we give a brief discussion of how the results for augmented lattices can be applied to subsets of $L$ which are regular with respect to an $L$-module.     

Studies of substituted dihydroxy-p-benzoquinones as precipitate-exchange reagents

Studies of the barium salts of bromanilic acid, nitranilic acid and polyporic acid show that they are not superior to barium chloranilate as reagents for determining sulfate. Improved syntheses of polyporic acid and atromentin are presented; two new syntheses of barium bromanilate, and one new synthesis of barium nitranilate and of barium polyporate are also presented. Ultraviolet absorption spectra show that polyporic acid forms a dimer in dimethylsulfoxide solution.     

Infrared and NMR study of some 2-styrylindolium dyes

A series of 18 molecules of the 2-styrylindolium dyes group is examined by means of infrared and ¹H NMR spectroscopy. The effect of electron-withdrawing and electron-releasing substituents on the spectral behavior of the compounds is assessed and the most appropriate structure for these molecules is suggested.     

An investigation of the critical liquid-vapor properties of dilute KCl solutions

The three parameters that define the critical point, temperature, pressure, and volume have been experimentally determined by means of filling studies in a platinum-lined system for five KCl solutions ranging from 0.006 to 0.568m. The platinum-lined vessels were used to overcome the problems with corrosion experienced by earlier workers. The critical temperature (t _c), pressure (P _c), and volume (V _c) were found to fit the equations $\begin{gathered} {\text{t}}_c = 374.14{\text{ }} + {\text{ }}16.602\sqrt {\text{m}} {\text{ }} + {\text{ }}41.740{\text{m }} \pm 0.5^ \circ C \hfill \\ {\text{P}}_c = 220.9 {\text{ }} + {\text{ }}135.164{\text{m }} + {\text{ }}41.173{\text{m}}^{\text{2}} {\text{ }} \pm {\text{ }}0.5 bars \hfill \\ {\text{V}}_c = 3.155{\text{ }} - {\text{ }}1.373\sqrt m {\text{ }} + {\text{ }}0.507{\text{m }} \pm {\text{ }}0.008cm^3 - g^{ - 1} \hfill \\ \end{gathered} $ from infinite dilution to 1.0m.     

Variational derivation and extensions of distributed approximating functionals

Summary Extensions of the "Distributed Approximating Functional (DAF) approach to approximating functions and their derivatives are given. The method, although inherently approximate, can be made arbitrarily accurate, numerically stable, and computationally efficient by appropriate choice of parameters. It also provides approximate representations of quantum operators which are analytic and which can be accurate. Differences between the DAFs and more standard basis set approaches are discussed in order to clarify the properties of the DAFs. Some illustrative examples are given.Supported in part under National Science Foundation Grant CHE92-01967.The Ames Laboratory is operated for the Department of Energy by Iowa State University under Contract No 2-7405-ENG82.Supported under National Science Foundation Grants CHE-8907429 and CHE-9403416.Supported under R.A. Welch Foundation Grant E-0608.Supported under National Science Foundation Grants CHE-8907429 and CHE-9403416.