Volumes of solid state ions and their estimation

Formula unit volume, Vm, has recently been identified as the key link to a number of thermodynamic functions and has given rise to an alternative approach to thermodynamics for modern inorganic materials (volume-based thermodynamics, VBT). In an earlier publication, we reported over 400 ion volumes for commonly encountered cations and anions derived from crystal structure data which can, in turn, be used to generate formula unit volumes for those ionic salts, for which crystal structure data, which is the preferred source of such volume data, is not available. The purpose of the present paper is to report a further 147 supplementary ion volumes. These are compared to ion volumes obtained from the summation of Hofmann's elemental volumes, a convenient and alternative approach for the estimation of Vm. It is shown that many elusive ion volumes can be estimated using these databases in tandem by adopting the newly proposed isomegethic rule and other volume additivity rules. Generation of volume data for new, hypothetical, and counterintuitive ions, as well as for traditional ions, is now a reality, as is demonstrated.     

Development and Evaluation of Gold 3D Cylindrical Nanoelectrode Ensembles

Gold 3D cylindrical nanoelectrode ensembles （NEEs）, 100 nm in diameter and 500 nm in length were prepared by electroless template synthesis in polycarbonate filter membranes, followed by selective controlled chemical etching. The morphology of the nanowires and cylindrical NEEs was imaged by scanning electron microscopy. The protruding nanoelectrodes were in good parallel order. EDX study showed that the nanoelectrode elements consisted of pure gold. The electrochemical evaluation of the 3D electrodes was conducted using the well known [Fe（CN）6]^3-/[Fe（CN）6]^4- couple. Cyclic voltammgrams （CV） show a very low double layer charging current and a higher ratio of signal to background current than 2D disc NEEs. Electrochemical impedance spectroscopy （EIS） indicates that the 3D cylindrical NEEs effectively accelerate the charge transfer process, which is in consistent with the results of CV. The linear relationship with a slope of 0.5 between lg Ipc and lg v shows that linear diffusion is dominant on the 3D cylindrical NEEs at conventional scan rates.     

Studies in 85% H3PO4—II : On the role of the α-terpinyl cation in cyclic monoterpene genesis

The fate of the α-terpinyl cation (4) in 85% phosphoric acid has been examined. In this medium, no products formed by nucleophilic attack by the solvent on the intermediate carbocations were observed. In contrast to all other studies, geraniol (1), nerol (2), linalool (3), and their acetate and phosphate esters all produced cyclized material as the major products; these included limonene (17), isoterpinolene (18), α-terpinene (19), γ-terpinene (20), 3-p-menthene (26), and p-cymene (27), but no terpinolene (16), and no identifiable bicyclic material. Evidence is presented that 17 does not arise from 4, which apparently is not the sole cationic intermediate formed during the cyclization process.     

A subjective Bayesian approach to the theory of queues I — Modeling

This is the first of an expository two-part paper which outlines a point of view different from that currently used in queueing theory. In both parts, the focus is on concepts. Here we adopt a personal probability point of view to all sources of uncertainty in the theory of queues and explore the consequences of our approach by comparing our results to those that are currently available. For ease of exposition, we confine attention to the M/M/1/ and the M/M/1/K queues. In Part I we outline the general strategy and focus on model development. In Part II we address the problem of inference in queues within the subjective Bayesian paradigm and introduce a use of Shannon's measure of information for assessing the amount of information conveyed by the various types of data from queues.     

Syntheses and structures of CsHo3Te5 and Cs3Tm11Te18 and the electronic structure of CsHo3Te5

Single crystals of CsHo₃Te₅ and Cs₃Tm₁₁Te₁₈ have been grown as byproducts in the synthesis of CsLnZnTe₃ (Ln=Ho or Tm) through the reaction of Ln, Zn, and Te with a CsCl flux at 850 °C. The crystal structures have been determined from single-crystal X-ray diffraction data. CsHo₃Te₅ crystallizes in space group Pnma of the orthorhombic system whereas Cs₃Tm₁₁Te₁₈ crystallizes in the space group C2/m of the monoclinic system. Each of the compounds adopts a three-dimensional structure; each possesses tunnels built from LnTe₆ octahedra that are filled with Cs atoms. The pseudo-rectangular tunnel in CsHo₃Te₅ is large enough in cross-section to accommodate two symmetrically equivalent Cs atoms. In the Cs₃Tm₁₁Te₁₈ structure there are two different sized tunnels: the smaller one is only large enough to host one Cs atom per unit cell whereas the larger one can accommodate two Cs atoms. The electronic structure of CsHo₃Te₅ was calculated. The band gap is estimated to be about 1.2 eV, consistent with the black color of the crystals.     

Synthesis and utilisation of 2,7′-diindolylmethanes and a 2-(2-indolyl)pyrrolylmethane as macrocyclic precursors

Treatment of 3-(4-chlorophenyl)-7-hydroxymethyl-4,6-dimethoxyindole with 3-(4-chlorophenyl)-4,6-dimethoxyindole results in the generation of two geometrically isomeric diindolylmethanes in addition to a novel triindolyl oligomer, which has been structurally characterised. The 2,7′-diindolylmethanes were found to be unstable under Vilsmeier formylation conditions, thus hampering macrocyle precursor construction. In an alternate approach, the 3-(4-chlorophenyl)-4,6-dimethoxyindole-7-carbaldehyde was converted into the indolyl-pyrrolyl macrocycle precursor 5-(3-(4-chlorophenyl)-4,6-dimethoxyindole-2-ylmethyl)-4-ethyl-3-methylpyrrole-2,7-dicarbaldehyde, which was used to generate an unsymmetrical pentaaza macrocycle.     

Green Oxidations. Manganese(II) Sulfate Aided Oxidations of Organic Compounds by Potassium Permanganate

Summary. The oxidation of arenes and sulfides by potassium permanganate was accomplished in good yields under solvent free and heterogeneous conditions when manganese(II) sulfate is used as a solid support. After extraction of the organic products, the inorganic products can be reoxidized to permanganate. This result is important because it provides an approach to oxidation reactions that is, in theory, infinitely sustainable.     

Biscavitands II: Self-Inclusion in a Back-to-Back Connected Biscavitand

A foot-to-foot or `back-to-back' connected biscavitand is prepared directly from a hexadecol resorcinarene precursor. The axial orientation of the biphenyl linker and hence the crown conformation of the hexadecol was established by an X-ray crystal study of the biscavitand. Each cavitand bowl is filled in the crystal by an alkyl `foot' from the next molecule, a self-inclusion which results in polymeric host–guest chains. The new biscavitand differs from previously prepared Z and C isomers of a bowl-to-bowl or `front-to-front' connected host, which crystallize as chains of carcerand-like, solvent-filled cages or as distinct molecules of hemicarceplex, respectively.     

Simple relationship between total molecular correlation energies and LMO sizes

As an alternative to the density functional approach to estimating total molecular correlation energies, the equation E_corr=?0.06593 ∑ R, where R_i=〈r²〉${}_{\text{i}}^{\text{½}}$ and i runs over the localized molecular orbitals was fitted to 25 STO -3G data points with a root-mean-square error of 0.025 hartree. Other more general equations were tried but no significant improvement was observed in the fit.