Prediction of the retention of β-diketonato complexes in TLC systems on silica gel by quantitative structure-retention relationships

Quantitative structure-retention relationships for a series of 30 mixed β-diketonato complexes of cobalt(III) , chromium(III) and ruthenium (III) were derived by multiple linear regression analy ses using molecular descriptors o b- tained by quant um chemical c alculations. The retention par ameters were o b- tained by thin l ayer chro matography on sili ca gel using mono and two-co m- ponent sol vent sy stems. The m olecular de scriptors include d in the multiple linear regressio n analy sis w ere molecular weight, molecular volu me, surfa ce area, hydrophilic-lipophilic balance, percent hydrophilic surface area, dip ole moment, polarizability, refractivity, energy of the high est occupied molecular orbital and energy of the lowe st unoccupied molecular orbital. High agreement between the experimental and predicted ret ention para meters wa s obtained when p olarizability and the h ydrophilic-lipophilic balance were used as the molecular de scriptors. Co mparison of the models with tho se est ablished on polyacrylonitrile showed that t he structure of the sorbent i s responsible for the chromatographic behaviour of the same compounds. The presented models can be used for th e prediction of t he retention of n ew solutes in screening chroma- tographic systems.