The synthesis of neutral metal complexes that partition to the membranes of lipid vesicles

Abstract

Life relies on membranes, electron transfer reactions and proton-gradients. To better understand if electron transfer within and proton gradients across a lipid membrane could be achieved with simple, prebiotically plausible components, we synthesized prebiotically plausible neutral metal complexes which are redox active. These metal complexes partitioned to the membranes of lipid vesicles and should be capable of participating in an electron transport chain. Here, different thiol ligands and imidazole ligands were first chosen and used to synthesize Co (II) complexes in water-octanol mixtures. According to the UV-Vis spectra of different Co (II) complex in octanol, the logic and method of octanol-soluble metal complex synthesis was obtained and then applied to the synthesis of Fe (II) complexes. The UV-Vis spectra indicated that octanol soluble Fe (II)-N-Acetyl-L-cysteine-1-butylimidazole complex was successfully synthesized. Subsequently, such complexes were synthesized in the membranes of phospholipid vesicles and detected by 31P NMR spectra. Increased linewidths indicated that Fe (II) complexes successfully migrated to the membranes of phospholipid vesicles.