Characterization of in Situ Generated Ionene Micellar Mimetic Stationary Phases for Liquid Chromatography

ABSTRACT

Micellar mimetic ionenes are linear cationic polyelectrolytic molecules having dimethylammonium charge centers interconnected by alternating alkyl chain segments containing x and y number of methylene groups where x is equal to 3 and y is greater than 14. These ionenes form intramolecular aggregates with behavior that mimics traditional surfactant micelle properties. In this paper we report the use of [3, 16]-ionene to prepare an in situ generated stationary phase on aminopropylated silica for liquid chromatography. This phase was found to exhibit chromatographic characteristics different from those of conventional amino, C-18 or phenyl stationary phases. This ionene column has facilitated the separation of some cis-, trans-, and ortho-, meta-, para-isomeric components, planar and non-planar aromatic hydrocarbons as well as alpha - beta ring attachment compounds.     

Chromatographic Separation of Cresol Isomers by a β‐Cyclodextrin: Application for the Determination of Volatile Phenols in Alcoholic Beverages

Abstract

The chromatographic separation of o‐cresol, m‐cresol, and p‐cresol by using β‐cyclodextrin as a chiral reagent has been studied. Conditions for the chromatographic separation of these isomers by using the cyclodextrin in the mobile phase or bonded in the stationary phase were optimized, and both procedures provided good results for the resolution of the chromatographic peaks. The use of fluorimetric detection (λ_exc 275 nm λ_em 300 nm) allows detection and quantification limits of the µg/L for eight studied phenols by using both procedures. The determination of volatile phenols in alcoholic beverages must be carried out using the cyclodextrin in the mobile phase because of the co‐elution of phenol and ethylguaiacol with other compounds of some studied matrix.     

On the interpretation of the Raman spectra of Maya Blue: a review on the literature data

The Raman spectroscopy of Maya Blue (MB), a nanostructured organic–inorganic hybrid material, has received considerable attention. A re‐evaluation of the Raman literature data for indigo dye, genuine MB samples and model specimens obtained by the binding of indigo to phyllosilicate clays, such as palygorskite and sepiolite, using chemometric analysis of normalised spectra is reported. Available data present features in support of the following ideas: (1) dehydroindigo accompanies indigo in MB; (2) different topological isomers, i.e. dye molecules attached to different coordinative sites of the palygorskite framework, are involved in MB; and (3) different procedures were probably used for preparing MB in ancient Mesoamerican civilisations. Copyright © 2010 John Wiley & Sons, Ltd.     

3-Aryl(hetaryl)-3-hydroxy-2-phosphorus-substituted acrylonitriles. Synthesis and experimental and theoretical conformational analysis

Under conditions of the phase transfer catalysis, acylation of (thio)phosphorylacetonitriles by (het)aroyl chlorides affords the Z-enol forms of C-acylation products in high yields. Their configurations were studied by IR spectroscopy, dipole moment measurements, and ab initio quantum-chemical calculations [B3LYP/6-31G(d)]. The C=C double bond and the phosphoryl or thiophosphoryl group have an s-cis arrangement. The possibility of strong intramolecular hydrogen bonding in these conformers is the governing factor responsible for the three-dimensional structures of the compounds under investigation. Derivatives of nicotinic acid existing in the individual form as zwitterions are the only exceptions.     

Regioselective Synthesis of 3- and 5-Functional Derivatives of Pyrazolidine. 1. Synthesis of Ketones of the Pyrazolidine Series

When 5-hydroxypyrazolidines reacted with ketones on the surface of basic adsorbents the 3-regioisomers were obtained in addition to the expected 5-oxoalkylpyrazolidines. The conditions for the regiodirection of the process have been found. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1566–1572, October, 2005.     

Calculations of IR-spectra of metastable bond isomers of ruthenium nitrosocomplexes [Ru(NO)Cl<Subscript>5</Subscript>]<Superscript>2−</Superscript> [Ru(NO)(CN)<Subscript>5</Subscript>]<Superscript>2−</Superscript> by DFT method

IR-spectra of stable and metastable isomers of ruthenium nitrosocomplexes, [Ru(NO)Cl₅]^2? and [Ru(NO)(CN)₅]^2?, have been calculated within the frames of density functional theory. Frequency assignment was refined on the base of analysis of normal vibration in internal vibrational coordinates. Calculation results confirm that spectrally observed metastable states are bond isomers with ν¹-ON and ν²-NO coordination.     

Gas chromatography of some prostaglandins

Summary The synthetic prostaglandin F_2α (PG_2α), used as an ovulation regulator, and abortion inducer, is contaminated with its Δ5-trans isomer. The ratio of the isomers was measured by capillary GC. The prostaglandin I₂ (PGI₂), a blood platelet aggregation inhibitor, easily decomposes to 6-ketoprostaglandin F_1α (6-keto PG_1α). Their ratio was measured by packed column GC. An unexpected, instantaneous methanol cleavage was observed during the GC analysis of the methyl ketal derivative of 6-keto PG_1α, forming a mixture of PGI₂ and Δ6-prostaglandin I₁ (Δ6-PGI₁). Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

富勒烯的电子模型物──丙烯酸甲酯的钼配合物(η~2-CH_2=CHCOOMe)_2Mo(CO)_2(biPy)的合成与结构表征

合成了富勒烯的电子模型物─丙烯酸甲酯联吡啶二碳基合钼的2个几何异构体，用X射线单晶衍射法测定了它们的晶体结构，研究了它们的红外光谱．     

GC/FTIR Potential for Structural Analysis of Marine Origin Complex Mixtures

Abstract

In this paper, we show the GC/FTIR contribution to the structural elucidation of marine origin complex mixtures. Three examples are given concerning aromatic hydrocarbons, fatty acid methyl esters and polychlorobiphenyls. These examples show the capability of GC/FTIR to differentiate isomers of aromatic hydrocarbons and polychlorobiphenyls and to rapidly characterize the different classes of fatty acid methyl esters (ramification, insaturation, cis/trans isomerism, hydroxyl group, cyclopropane ring).