A comparison of crystallographic and NMR data for thieno[2,3‐b:4,5‐b′]dipyridine and its monohydroperchlorate salt

X‐ray crystallographic studies of thieno[2,3‐b:4,5‐b′]dipyridine ( 1 ) and its monohydroperchlorate salt ( 1a ) show that 1 is protonated at N1 in ring A and not at N6 in ring C. In each compound individual rings are planar, but there is a small dihedral angle‐of‐twist between the A and C rings. On going from 1 to 1a the largest changes in bond angles and bond lengths occur in ring A. ¹H and ^l3C nmr spectra of 1 plus the ¹³C nmr spectrum of 1a are reported.     

Algebraic time-reversal operation

We analyze the implementation of the time-reversal (TR) transformation in the algebraic approach to tetrahedral local molecules through the chain of groups U(5) é U(4) é K(4)=A(4)ùS(4) é S(4) ? T_dU(5)\supset U(4)\supset K(4)=A(4)\wedge S(4)\supset S(4)\approx T_d. We determine the general form of the TR operation using a purely algebraic realization, based exclusively on the requirement that the irreducible representations must not be changed under the time inversion symmetry. As a result we can determine the TR behavior of purely algebraic operators.     

Separation of sialyl-oligosaccharides by high-performance liquid chromatography. Application to the analysis of mono-, di-, tri- and tetrasialyl-oligosaccharides obtained by hydrazinolysis of alpha 1-acid glycoprotein

High-performance liquid chromatography has been applied to the separation of isomers of mono-, di-, tri- and tetrasialylated oligosaccharides derived from alpha 1-acid glycoprotein by hydrazinolysis. The separation of the sialyl-oligosaccharides on the basis of their negative charges was carried out with quaternary amine-bonded silica. Within each class, the anionic oligosaccharides were fractionated on the basis of their net carbohydrate content on alkylamine-modified silica using a mobile phase consisting of a mixture of acetonitrile and potassium dihydrogen phosphate with 0.01% of 1,4-diaminobutane or 0.01% of tetraethylpentamine.     

High resolution study of the six lowest doubly excited vibrational states of PH2D

The five lowest doubly excited deformational vibrational bands ν₄ + ν₆, 2ν₆, ν₃ + ν₄, ν₃ + ν₆, and 2ν₃ of PH₂D have been recorded for the first time using a Bruker 120 HR interferometer with a resolution 0.0033 cm⁻¹ and analysed. Some transitions belonging to a very weak band 2ν₄ have been also assigned. From the fit 24 and 86, respectively, diagonal and resonance interaction parameters were obtained which reproduce 1089 upper energy levels obtained from more than 4600 assigned transitions with the rms deviation of 0.00059 cm⁻¹.     

Nanoscale polyoxometalate‐based inorganic/organic hybrids

The latest advances in the area of polyoxometalate (POM)‐based inorganic/organic hybrid materials prepared by self‐assembly, covalent modification, and supramolecular interactions are presented. This Review is composed of five sections and documents the effect of organic cations on the formation of novel POMs, surfactant encapsulated POM‐based hybrids, polymeric POM/organic hybrid materials, POMs‐containing ionic crystals, and covalently functionalized POMs. In addition to their role in the charge‐balancing, of anionic POMs, the crucial role of organic cations in the formation and functionalization of POM‐based hybrid materials is discussed. DOI 10.1002/tcr.201100002     

Exploring the structure and properties of transition metal templated {VM17(VO4)2} Dawson-like capsules

Vanadate(V)-templated Dawson-type capsules {V(IV)M(VI)(17)(VO(4))(2)} (M = Mo, W; 1-2) have been synthesized and investigated by electrochemical methods in aqueous and organic media using spectroscopic techniques, EPR, UV-vis/NIR, IR, and CSI-MS (cryospray ionization mass spec.), and the clusters have been examined in the solid state by magnetic studies. The collision-induced dissociation (CID-MS) studies confirmed the solution structures as well as helped pinpoint the position of the vanadium ion on the {VM(17)}-type shell, which was corroborated by EPR and theoretical studies.