Two new steroidal glucosides from Ophiopogon.japonicus （L.f.） Ker-Gawl

Two new steroidal glucosides, 26-O-β-D-glucopyranosyl （25S）-furost-5-ene-1β,3β,22α,26-tetraol l-O-β-D-xylopyranosyl- （1 → 3）-[α-h-rhamnopyranosyl-（1 → 2）]-[β-D-fueopyranoside and （25R） spirost-5-ene-3β,14α-diol-3-β-O-β-L-rhanmopyranosyl- （1 → 2）-[β-D-xylopyranosyl（1 → 4）]-[-β-D-glucopyranoside, were isolated from the Ophiopogon japonicus （L.f.） Ker-Gaw. Their structures were elucidated by spectroscopic methods.     

ChemInform Abstract: Anionic Ordering in Ba15V12S34O3, Affording Three Oxidation States of Vanadium and a Quasi‐One‐Dimensional Magnetic Lattice.

Polycrystalline Ba₁₅V₁₂S₃₄O₃ is prepared by solid state reaction of a 12:3:12:22 molar mixture of BaS, BaO, V, and S under 200 mbar Ar (corundum crucible in sealed quartz tube, 1.     

Equivalent Conditions for Jacobian Nonsingularity in Linear Symmetric Cone Programming

In this paper we consider the linear symmetric cone programming (SCP). At a Karush-Kuhn-Tucker (KKT) point of SCP, we present the important conditions equivalent to the nonsingularity of Clarke’s generalized Jacobian of the KKT nonsmooth system, such as primal and dual constraint nondegeneracy, the strong regularity, and the nonsingularity of the B-subdifferential of the KKT system. This affirmatively answers an open question by Chan and Sun (SIAM J. Optim. 19:370–396, 2008).     

Group 13 Lewis acid adducts of [PCl2N]3

Phosphazene polymers are classically synthesized by the high-temperature, ring-opening polymerization (ROP) of [PCl(2)N](3) to give [PCl(2)N](n), followed by functionalization of [PCl(2)N](n) with different side groups. We investigated the interactions of [PCl(2)N](3) with Lewis acids because Lewis acids have been used to induce the high-temperature ROP of [PCl(2)N](3). The reactions of [PCl(2)N](3) with MX(3) (M = group 13, X = halides), under strict anaerobic conditions gave adducts [PCl(2)N](3)·MX(3). Adducts were characterized by X-ray crystallography and multinuclear and variable-temperature NMR studies, and mechanistic understanding of their fluxional behavior in solution was achieved. The properties of the [PCl(2)N](3)·MX(3) adducts at or near room temperature strongly suggests that such adducts are not involved directly as intermediates in the high-temperature ROP of [PCl(2)N](3).     

Interpretation of matrix-assisted laser desorption/ionization postsource decay spectra of charge-derivatized peptides: Some examples of tris[(2,4,6-trimethoxyphenyl) phosphonium]-tagged proteolytic digestion products of phosphoenolpyruvate carboxykinase

The fragmentation of peptides, to which a positive charge is attached at the N-terminus, was studied by matrix-assisted laser desorption/ionization postsource decay mass spectrometry. In these experiments, the tris[(2,4,6-trimethoxyphenyl)phosphonium] acetyl group is covalently attached. The main advantage of this modification is that the resulting spectra are simplified and the fragment ions observed consist predominantly of a(n)-type ions. We report the results for charge-derivatized peptides formed following enzymatic digestion of phosphoenolpyruvate carboxykinase. Specific fragmentation of bonds within aspargine and threonine residues are observed and are discussed. The understanding of the mechanistic aspects of the fragmentation process is essential to formulate a simple and straightforward mass spectrometric strategy for peptide sequencing using these charged derivatives.     

Crystal Structures of Tetrakis‐(4‐chlorophenylthio)‐butatriene and Tetrakis‐(tert‐butylthio)‐butatriene

Tetrakis‐(4‐chlorophenylthio)‐butatriene (3a) and tetrakis‐(tert‐butylthio)‐butatriene (3b) were synthesized, and their crystal structures were determined. The compound 3a is monoclinic, space group P2₁/c, a=6.9785(8), b=8.6803(9), c=22.884(2) Å, β=93.887(6)^o, V=1383.0(3) ų, Z=2. The compound 3b is monoclinic, space group P2₁/n, a=11.0615(6), b=10.8507(4), c=11.2717(6) Å, β =116.427(2)^o, V=1211.5(1) ų, Z=4. The title compounds 3a and 3b reside on an inversion center so that only half of the molecule is crystallographically unique. Both compounds are not planar. The crystal structures of 3a and 3b have cumulated double bonds. The C7–C8–C8ⁱ and C5–C6–C6ⁱ angles that show the linearity in both structures, respectively, are 176.4(3)° in 3a and 175.6(2)° in 3b.     

EXPONENTIAL STABILITY TO A NEUTRAL DIFFERENTIAL EQUATION OF FIRST ORDER WITH DELAY

In this paper, we study the exponential stability of the zero solution to a neutral diferential equation. By applying the Lyapunov-Krasovskiì functional approach, we prove a result on the stability of the zero solution. The result we obtained extends and generalizes the existing ones in the previous literature. Comparing with the previous results, our result is new and complements some known results.     

Novel Terpyridine-bridged Parallel Dication Metallo-bisviologens and Their Supramolecular Complexes

By utilizing terpyridine-bridged parallel metallo-complexes as dication metallo-bisviologens,herein we present the synthesis and characterization of two novel supramolecular complexes.1-Methylpyridin-1-ium-terpyridine ligands and their metallo-complexes were first designed and synthesized,and the association of methyl-pyridiniums with dibenzo-24-crawn-8 ether(DB24C8)afforded the desired novel complexes through host-guest interactions.The self-assembly behavior of the supramolecular complexes was comprehensively investigated and could be exploited for furtlaer construction of ID to 3D supramolecular infrastructures.     

Instability of solutions for certain nonlinear vector differential equations of fourth order

The main purpose of this paper is to give a result with explanatory example that deals directly with the instability of the trivial solution of a certain nonlinear vector differential equation of the fourth order. The result established here improves and includes a well-known instability result established for a scalar nonlinear differential equation of the fourth order. Published in Neliniini Kolyvannya, Vol. 12, No. 1, pp. 120–129, January–March, 2009.