Vakarov S. Synthesis and properties of asymmetrically substituted iron(II) clathrochelate complexes

The dissertation presents new methods for the synthesis of iron(II) clathrochelate complexes with different aryl- and alkylsulfide substituents on one rib both by step-by-step nucleophilic substitution of known and relatively readily available dihalogenoclathrochelate complexes and functionalization of complexes with terminal carboxy groups. A strategy for the synthesis of disubstituted clathrochelate complexes with the following substituents on one rib is proposed: with two terminal carboxy groups; with carboxy and ester groups, with carboxy and amide groups; with two amide groups; with two ester groups. In total, 32 new complexes were synthesized. Their composition and structure were established. The structures of four of the complexes were obtained by X-ray diffraction analysis of single crystals. Optical activity of iron (II) clathrochelate complexes were discovered for the first time. Model compounds with covalently coupled optically active inductor (R-phenylethylamine) have been synthesized. In the presence of such inductor, a response appears in the spectra of circular dichroism (CD). Based on the study of the chirooptical properties of iron(II) clathrochelate complexes, the dependence of the intensity in the CD spectra of clathrochelate complexes on the location and type of chiral inductor was established. Using quantum chemical methods, theoretical CD spectra for both enantiomers of clathrochelate complex were calculated and compared with the experimental ones. Based on this comparison the preferable conformation of the clathrochelate’s polyhedra in solution was found. A possible mechanism of chirality induction is proposed, according to which the main way of transmission of such induction is the interaction of an optical inductor with aromatic rib substituents. Due to their conjugation with the macrobicyclic framework, the conformation of the rib substituents influence the conformation of the metal polyhedron, which causes the formation of CD spectra. The dissertation also presents a brief study of the structural features of clathrochelate complexes that lead to the formation of stable supramolecular complexes "clathrochelate - protein".