The synthesis and chromatographic properties of novel selective complexation by the molecular tweezers on the silica surface. As expected from the solution experiments, chemically-bonded stationary phases CBSP-1 and CBSP-2, containing substituted molecular tweezers with benzene and higher capacity factors and selectivities were obtained with CBSP-2 than with CBSP-1 because of a better structural fit of naphthalene spacer-units, are described. These phases selectively retain electron-deficient aromatic and quinoid the naphthalene-spaced receptor with the aromatic analytes.
Capacity factors, kЈ, and enthalpies of retention, ∆H R , were analytes of appropriate size and topography, such as 1,4dinitrobenzene, 1,2-, 1,3-, and 1,4-dicyanobenzenes, and measured for four different aromatic analytes in 15 solvents. Chromatographic separation factors, α, were determined for 7,7,8,8-tetracyano-p-quinodimethane (TCNQ), in HPLC studies. The good qualitative correlation between the seven structurally-related nitroaromatic compounds. The results of these measurements allow for the conclusion that capacity factors kЈ derived from the HPLC retention times and the association constants K a obtained from binding the electrostatic nature and steric complementarity of the receptors and analytes is most important in determining studies in solution using molecular tweezers 1 and 2 as receptors, indicates that the mechanism of retention involves selectivities.
analytes due to the highly selective complexation properties
Results and Discussion