A molecular loop with interstitial channels in a chiral environment and study of formation of metal-metal bonds in dinickel, dipalladium and dititanium complexes

摘要

This dissertation consists of two independent topics: (1) a molecular loop withinterstitial channels in a chiral environment; (2) study of formation of metal-metal bondsin dinickel, dipalladium and dititanium complexesOn the first topic, a study of the reaction products of the interaction of cis-Mo2(DAniF)2(CH3CN)42+ corner pieces with ortho-, meta- and para- isomers ofenatiomerically pure ??O2CCH(CH3)C6H4CH(CH3)CO2?? dicarboxylate was performed.First, an enantiomerically pure molecular loop based on two dimolybdenum units andtwo para-dic arboxylate linkers was synthesized and structurally characterized. Similarreactions with isomeric ortho- and meta- dicarboxylate linkers, as well as with somenonchiral ligands, showed that the structure of the obtained products depends on thegeometry of the ligand. Meta- dicarboxylate linker favors the formation of the chelatedproduct and ortho- dicarboxylate linker produces the mixture of chelated molecules andloops. On the second topic, an investigation of the formation of metal-metal bonds wasperformed. Study of the one-electron bond obtained upon oxidation of Ni24+ and Pd24+ toNi25+ and Pd25+, respectively, was made. The compounds synthesized were studied withvarious physical methods, such as X-ray crystallography, UV-visible spectroscopy andEPR spectroscopy. The nature of oxidized species as well as the dependence of metalmetalinteractions on electron-donating abilities of bridging ligands was studied. It wasshown that oxidation takes place on a metal center. The formation of one-electron bondin oxidized species is proposed.Finally formation of Ti26+ single bonded compounds by the reduction of two Ti4+monomers to Ti26+ dimer was studied. The nature of the species obtained in solution andin solid state is discussed. The crystal structure shows the presence of two types of hppligands ?? chelating and bridging. NMR study of this compound in solution proposes therearrangement of this structure to a paddlewheel.