Hydroxylated derivatives of coenzyme Q1 as ligands for complexation of transition metals

Coenzymes Q (CoQ) are omnipresent molecules in livi ng systems, which in addition to being members of mitochondrial respiratory chain, possess several other functions of great importance for the cellular metabolism. They are among the most ap pealing redox active quinone derivatives. In mammals, the predominant homologue is CoQ 10 (ubiquinone). Unlike CoQ10 which is lipophilic, its analogue CoQ1 is much more hydrophilic, because contains only one instead of 10 isoprenoid groups i n the tail. The main purpose of using CoQ1 was to serve as a model for exploring redox properties of CoQ group in aqueous medium. In an alkaline medium, CoQ1 s can be hydroxylated at the quinoid ring. The chemical transformations of CoQ1 in an alkaline medium has been studied by means of cyclic and square-wave voltammetry and it is showed that upon substitution of methoxy groups, hydroxylated derivatives of CoQ1 are formed. The new hydroxilated derivatives exhibit distinct redox properties compared to the parent compound, as well as a profound complexing a ctivity of transition metal cations such as Fe3+ and Co2+. Besides application of electrochemical techniques, to confirm further the chemical reaction and the structural changes of CoQ1 in a strong alkaline medium and to investigate the complexing activity of metal cations, a set of spectroscopic experiments has been performe