Aminopropyl-silica gel modified with nickel(II)-phthalocyanine for separation of pi-electron rich compounds by high performance liquid chromatography

Aminopropyl-silica gels modified with a nickel(II)-phthalocyanine derivativ e (Ni-PCSD) were evaluated as HPLC-stationary phases for the separation of pi-electron rich compounds such as polyaromatic hydrocarbons (PAHs) and mut agens. A column packed with Ni-PCSD retains some pi-electron rich compounds longer than a column packed with copper(II)-phthalocyanine derivatives (Cu -PCSD), suggesting that a pi-pi electron interaction and an additional inte raction between Ni-PCS and the compound. On the basis of the retention data of four-ring PAHs, anthracene derivatives and heterocyclic aromatic hydroc arbons, we propose that the additional interaction would be due to an inter ference of the pi- or n-electrons would interact and with the d-orbital of the Ni atom in Ni-PCS. Further, the Ni-PCS, column is expected to be superi or to the Cu-PCSD column for the separations of drugs, mutagens and polluta nts which have both pi-electrons and ligand atom(s).