Lipophilicity of metallic complexes of 4-methoxyphenyl-4 '-chlorobenzoylhydrazine as estimated from principal component analysis of thin layer chromatographic retention data

The relative lipophilicity of ten metallic complexes of 4-methoxyphenyl-4'- chlorobenzoylhydrazine with Cu2+, Co2+, Mn2+, Ni2+, Pd2+, Fe3+, C3+, La3+, Ce4+ and UO22+ with potentially anti-inflammatory properties have been dete rmined by reversed-phase thin-layer chromatography using C-18 plates and wa ter-methanol mixtures as eluents. The R-F values of each compound increased linearly with increasing concentration of methanol in the eluent. Principa l component analysis allowed a more rational and objective estimation and c omparison of lipophilicity determined by RPTLC. Scatterplots of the scores onto a plane described by the first two components showed clustering of the complexes according to the nature of the central cation, obtaining in this way a "congeneric lipophilicity chart". Generally, the presence of cation increases the lipophilicity expressed as scores along the first principal c omponent, practically in the same way. This means that the lipophilic behav ior of metallic complexes depends firstly of the structure of ligand. Howev er, the most lipophilic effect was observed in the case of Cu2+, Pd2+, La3 and Cr3+.