Effect of octabromination of a tetrakis(4-carboxyphenyl)porphine derivative bound to silica gels on HPLC retention behaviors of polyaromatic hydrocarbons.

The effect of bromination of Cu-porphyrin-derivative-immobilized silica gels (Cu-TCPP(D)) was examined by comparing the retention behaviors of polyaromatic hydrocarbons (PAHs) on Cu-TCPP(D) and Cu-octabromotetrakis(4-carboxyphenyl)porphine-derivative-immobilized silica gels (Cu-OBTCPP(D)) columns. It was revealed that bromination affects strongly the pi-pi electron interactions caused from hydration energy in a polar eluent (80% methanol) possibly as a result of a destruction of planar structure of porphine-ring by bromination. It was also revealed that bromination enhances pi-d interactions as well as the pi-pi electron interactions in a broad sense (e.g., dispersion forces) in a non-polar eluent (n-hexane). However, the bromination did not exert much influence on electrostatic interactions caused from polarization of mono-halogenated benzenes.