PREPARATION OF A CYCLOPHANE-BONDED STATIONARY-PHASE AND ITS APPLICATION TO SEPARATION OF NAPHTHALENE DERIVATIVES

A cyclophane (CP44)-bonded silica gel stationary phase was prepared an d elution behaviour of hydrophobic solutes was investigated in the rev ersed-phase mode. Aromatic compounds were retained on the stationary p hases more strongly than the corresponding alicyclic compounds, as was expected by the complex-forming ability of the cyclophane. The statio nary phases also showed isomer-selective separation for monomethyl-and dimethylnaphthalenes. The isomers having methyl groups at the alpha-p osition were eluted prior to those having methyl groups at the beta-po sition, i.e., the retention order for methylnaphthalene was, alpha<bet a and that for dimethylnaphthalene, alpha,alpha<alpha,beta<beta,beta. Moreover, some dimethylnaphthalene isomers which cannot be separated o n ordinary reversed-phase stationary phases were separated finely on t his stationary phase. The separation mechanism is discussed on the bas is of the structure of the cyclophane-involved complex. (C) 1998 Elsev ier Science B.V.