engleski

Ferrocene derivatives as flexible model systems to study the effect of chirality on hydrogen-­bonding patterns

Ferrocene-­based peptidomimetics have already proven as flexible and efficient templates to study intramolecular hydrogen bonds formed within or between small peptide chains attached to cyclopentadienyl rings of a ferrocene unit. These compounds also show a great potential to mimic secondary structures of proteins acting as turn inducers and some of them even exhibit self-­assembly and gelation properties. An opposite chirality of a single amino acid can promote different hydrogen-­bonding patterns. Favorable intermolecular interactions found in the crystal structure can trigger conformational changes of single molecules from the most stable conformer they adopt in solution to energetically less favorable form observed in the solid state. If we want to predict the structural properties of ferrocene-­based peptidomimetics, firstly we need to fully understand the conformational preferences of small modeling compounds. Recently, we prepared ferrocene derivatives like FcCO–Pro–Ala–NHFc to test the effect of heterochiral vs. homochiral amino acid sequence on different hydrogen-­bonding patterns. These compounds are dinuclear derivatives and exhibit different chiro-­optical properties in comparison with the previously synthesized derivatives bearing only one ferrocene unit. We performed a detailed conformational study by means of computational chemistry methods (DFT, QTAIM) to get a deeper insight into their structural preferences and fine-­tuning properties. In addition, results were compared with those obtained by experimental techniques (IR, NMR, CD).

ferrocene peptidomimetics, hydrogen bond, conformational analysis, Density Functional Theory

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