Dithia [3.3] Paracyclophane-Based Monometal Ruthenium Acetenyl Complexes:Synthesis,Characterization And Substituent Effects

π-π interactions as a kind of noncovalent interactions, exists widely in biological systems, which have significantly effect in the DNA molecule. Understand how the π-π interactions influence the elentron transfer progress would be of importance in research the biological activities. It has been proved that substitutents can influence the strength of π-π interactions largely, which can be tuned well by introducing substitutents with different electronic effect into the interactive benzene rings.Nowdays, there are rarely reports on how the substitutents affect the strength of intermolecule π-π interactions. Therefore, we choose dithia[3.3]paracyclophanes that contains transannular π-π interaction as substrates, introducing different eletronic effect (electron-donating or electron-withdrawing) substituents onto clophane unit, systematically investigate the effects of π-π interaction and substitutents onto the redox-active metal center. The concrete work are shown as follows:1. Six monometallic ruthenium acetylide complexes (2-5a-2-5e and2-8) have been designed and synthesized, in which dithia[3.3]metaparacyclophanes with substituent on the upper-layer benzene ring and the metal end are bridged by acetylide. These complexes have been characterized by NMR, UV-vis, and elemental analyses, the structure of complexes2-3c、2-5a and2-8have been confirmed by X-ray crystal diffraction. The crystal structure of-CN substituted complex2-3c exhibits a asymmetric molecular configuration, the torsion angle between the benzene rings is17.64°and the distance between the benzene rings is3.882A, that is the evidence to prove that there are π-π interactions in all of the complexes. The distance between the benzene rings in the complexe2-5a is3.882A. Electrochemistry studies revealed that the electrons density of ruthenium center can be influenced by intramolecular π-π interaction.2. Eight monometallic ruthenium acetylide complexes (3-5a-3-5f and3-8) have been designed and synthesized, in which dithia[3.3]metaparacyclophanes with substituent on the under-layer benzene ring and the metal end are bridged by acetylide. These complexes have been characterized by NMR, UV-vis, and elemental analyses, the structure of complexes3-3d%2-5e and2-5f have been confirmed by X-ray crystal diffraction. The crystal structure of-tetraCH3substituted complex3-3d exhibits a asymmetric molecular configuration, the torsion angle between the benzene rings is16.37°and the distance between the benzene rings is3.620A. The torsion angle and the distance between the benzene rings in complexes2-5e and2-5f are7.18°,3.189A and16.37°,3.244A, respectively. Electrochemistry studies revealed that the Ep values of di-substituted complexes (3-5b-3-5d) are larger than unsubstituted complexe (3-5a), especially the complex3-5c. The electrons density of ruthenium center influenced by the substituents in dithia[3.3]metaparacyclophanes through the intramolecular π-π interaction, regardless of the eltronic properties of substituents.3. In order to understand how the substituents influence the π-π interaction under the condition that the benzenes are accumulation face-to face, we designed and synthesized complexes (4-5a-4-5c). These complexes have been characterized by NMR, UV-vis, and elemental analyses. The distance between the benzene rings in the di-CN substituted complex4-3b is3.406A. Electrochemistry studies revealed that the dedox petentials of ruthenium have changed a lot by introduced dithia[3.3] paracyclophanes to the metal complexes, but regardless of the eltronic properties of substituents. The electrons density of ruthenium center can be influenced by intramolecular π-π interaction...