Synthesis, Crystal Structure And Catalytic Properties Of Ruthenium Complexes Containing Bi-or Tri-dentate Schiff-base Ligands

Syntheses, structures and catalytic properties of a series of ruthenium complexescontaining bi-or tri-dentate Schiff-base ligands were reported in this thesis. Fivecommon ruthenium starting materials were initinally synthesized from RuCl3·3H2Oand then seven bidentate (HL1HL7) and two tridentate (HL8HL9) Schiff-baseligands were prepared from the reaction of salicylaldehyde with equal equivalent ofprimary amines in ethanol solution.Treatment of Ru(NO)Cl3with seven different bidentate (HL1HL7) Schiff-baseligands in THF in the presence of Et3N afforded seven different ionic rutheniumcomplexes [Et3NH][(Lx)Ru(NO)Cl3](x=17), respectively. Structural determinationthrough single-crystal X-ray diffraction revealed that the geometries around Ru ofcomplexes17were distorted octahedral, in which the Cl atom, NO and N, O atom ofSchiff-base ligands occupied the equatorial position and the remaining two Cl atomsoccupied the axial position.Interaction of tridentate Schiff-base ligand (HL8) containing S-N-O donor with[Ru(CO)2Cl2]2or RuCl3·3H2O afforded ruthenium complexes [(L8)Ru(CO)Cl2](8),[(L8)Ru(CO)2Cl](9) and [(L8)RuCl3](10), respectively. From the conformation ofcomplexes8,9and10, the S-N-O and Cl or CO ligand around Ru centre occupied theequatorial position, while remaining two ligands occupied the axial position，whichformed a typical hexa-coordination octahedral. Interaction of complex10withsandwich-structural [(η6-1,2,3,4-tetramethylbenzene)RuCp*] in the presence ofNaOH led to the formation of diruthenium complex [(L8)RuCl3][RuCp*(η6-1,2,3,4-tetramethylbenzene)](11); whereas the dimerization reaction of complex10in thepresence of AgNO3formed a novel sulfur-bridged dinuclear ruthenium complex[(L8)3Ru2Cl](12).The reaction of tridentate Schiff-base ligand (HL9) containing N-N-O donorwith [Ru(PPh3)3Cl2],[Ru(THT)4Cl2] or [Ru(CO)2Cl2]2obtained ruthenium complexes[(N-N)Ru(PPh3)Cl3](13),[(L9)Ru(CO)Cl2](14), or [(L9)Ru(THT)Cl2](15) respect-ively. Coordination of o-Phenylenediamine from the decomposition of tridentateSchiff-base ligand (HL9) to Ru centre directly led to the formation of complex13.Thecoordination geometry around Ru of complexes14and15were distorted octahedral, in which N-N-O atom and CO or THT around Ru centre occupied the equatorialplanar, while the remaining two ligands occupied the axial position，which formed atypical hexa-coordination octahedral conformation.All complexes were well characterized by IR and NMR spectroscopies alongwith elemental analyses. Catalytic activity of complexes was explored through theirapplication to oxidation of primary or secondary alcohol and epoxidation reaction ofstyrene or methyl styrene. GC analysis found that the catalytic reactions had arelatively good conversion rate and selectivity, which suggested that rutheniumcomplexes containing Schiff base ligands probably may be a kind of catalytic reagentsfor catalytic oxidation.