Estimation of descriptors for hydrogen-bonding compounds from chromatographic and liquid-liquid partition measurements.

Retention factors obtained by gas chromatography and reversed-phase liquid chromatography on varied columns and partition constants in different liquid-liquid partition systems are used to estimate WSU descriptor values for 36 anilines and N-heterocyclic compounds, 13 amides and related compounds, and 45 phenols and alcohols. These compounds are suitable for use as calibration compounds to characterize separation systems covering the descriptor space E=0.2-3, S=0.

A system map for the ionic liquid stationary phase 1,12-di(tripropylphosphonium)dodecane bis(trifluoromethylsulfonyl)imide for gas chromatography.

The solvation parameter model is used to prepare a system map for the retention of volatile organic compounds on the ionic liquid stationary phase 1,12-di(tripropylphosphonium)dodecane bis(trifluoromethylsulfonyl)imide (SLB-IL60) by gas chromatography over the temperature range 80-280°C. Retention is governed by dispersion, dipole-type and hydrogen-bonding interactions with a different temperature dependence. The hydrogen-bond acidity of the SLB-IL60 column is unexpected since the stationary phase contains no hydrogen-bond acid groups and is not obviously connected to contributions from the deactivated column wall.

System map for the ionic liquid stationary phase tri(tripropylphosphoniumhexanamido)triethylamine bis(trifluoromethylsulfonyl)imide for gas chromatography.

The solvation parameter model is used to construct a system map for the retention of volatile organic compounds on the ionic liquid stationary phase tri(tripropypphosphoniumhexanamido)triethylamine bis(trifluoromethylsulfonyl)imide (SLB-IL76) over the temperature range 80-240°C. The SLB-IL76 stationary phase is moderately cohesive and strongly dipolar/polarizable and hydrogen-bond basic but only a weak hydrogen-bond acid. Electron lone pair interactions are weak and make only a minor contribution to the retention mechanism.

A system map for the ionic liquid stationary phase 1,12-di(tripropylphosphonium)dodecane bis(trifluoromethylsulfonyl)imide trifluoromethanesulfonate for gas chromatography.

The solvation parameter model is used to prepare a system map for the retention of volatile organic compounds on the ionic liquid stationary phase 1,12-di(tripropylphosphonium)dodecane bis(trifluoromethylsulfonyl)imide trifluoromethanesulfonate (SLB-IL61) over the temperature range 80-260°C. Retention is governed by dispersion, dipole-type and hydrogen-bonding interactions each with its own temperature dependence. The exchange of a bis(trifluoromethylsulfonyl)imide anion in SLB-IL60 for a trifluromethanesulfonate anion (SLB-IL61) results in a change in selectivity indicated by an increase in the hydrogen-bond basicity and a decrease in hydrogen-bond acidity of the stationary phase without change in either the cohesion or dipolarity/polarizability of the stationary phases.

Divergent reactivity of a new dinuclear xanthene-bridged bis(iminopyridine) di-nickel complex with alkynes.

The reaction of a dinucleating bis(iminopyridine) ligand L bearing a xanthene linker (L = N,N'-(2,7-di-tert-butyl-9,9-dimethyl-9H-xanthene-4,5-diyl)bis(1-(pyridin-2-yl)methanimine)) with Ni(COD)(DPA) (COD = cyclooctadiene, DPA = diphenylacetylene) leads to the formation of a new dinuclear complex Ni(L)(DPA). Ni(L)(DPA) can also be obtained in a one-pot reaction involving Ni(COD), DPA and L. The X-ray structure of Ni(L)(DPA) reveals two square-planar Ni centers bridged by a DPA ligand.

Applications of the solvation parameter model in reversed-phase liquid chromatography.

The solvation parameter model is widely used to provide insight into the retention mechanism in reversed-phase liquid chromatography, for column characterization, and in the development of surrogate chromatographic models for biopartitioning processes. The properties of the separation system are described by five system constants representing all possible intermolecular interactions for neutral molecules. The general model can be extended to include ions and enantiomers by adding new descriptors to encode the specific properties of these compounds.

Gas chromatography on wall-coated open-tubular columns with ionic liquid stationary phases.

Ionic liquids have moved from novel to practical stationary phases for gas chromatography with an increasing portfolio of applications. Ionic liquids complement conventional stationary phases because of a combination of thermophysical and solvation properties that only exist for ionic solvents. Their high thermal stability and low vapor pressure makes them suitable as polar stationary phases for separations requiring high temperatures.

Estimation of the environmental properties of compounds from chromatographic measurements and the solvation parameter model.

This article provides an overview of chromatographic methods as surrogate models for environmental processes and for the determination of descriptors for compounds of environmental interest. The solvation parameter model is the link to the identification of suitable chromatographic models for the estimation of environmental properties using a set of tools that allow screening of chromatographic databases for the selection of candidate systems. As an alternative approach, many transport and distribution properties of environmental interest can be described directly by the solvation parameter model.