Study On The Synthesis Characterization And Catalytic Alcohol Oxidation Reactions Of Ruthenium Carbonyl Complexes Containing Pyridineethanol

Pyridine alkoxide as a kind of bidentate ligand with excellent coordination ability can coordinate with various transition-metals leading to the formation of stable metal complexes.Transition metal compounds with novel structure can be synthesized from pyridine alkoxide bearing different substitutions and as catalyst widely applied in many fields such as polymerization of olefin,coupling reaction and oxidation of alcohol.Up to now,only a few carbonyl complexes bearing pyridine alkoxide ligands were reported.Here,the reactivity of pyridine alkoxides[C₅H₄N-2-CH₂-CH（OH）-C₆H₄-R]with Ru₃（CO）₁₂ was studied.Nine kinds of ruthenium complexes including:five kinds of trinuclear ruthenium carbonyl complexs,one kinds of dinuclear ruthenium carbonyl complexs and three kinds of mononuclear ruthenium carbonyl complexs were obtained.In addition,we also studied the catalytic activity of these complexes in alcohol oxidation.The details are listed as follows:（1）Six different functional groups pyridine-containing alcohol compounds PyCH₂CH（Ar）OH[Ar=p-OMePh（1a）;p-BrPh（1b）;p-CF₃Ph（1c）;o-BrPh（1d）;o-CF₃Ph（1e）;R₁=CH₃;R₂=Ph（1f）;]were designed and synthesized,and then refluxed with Ru₃（CO）₁₂intoluenefor.Fivekindsoftrinuclearrutheniumcarbonylcomplexs{?-η²-[（2-C₅H₄N）CH=C（O）（C₆H₄-4-R）]}₂Ru₃（CO）₈[R=OMe（2a）;Br（2b）;CF₃（2d）],{?-η²-[（2-C₅H₄N）CH₂-CH（O）（C₆H₄-2-R）]}₂Ru₃（CO）₈[R=Br（2g）;CF₃（2h）],one kinds of dinuclearrutheniumcarbonylcomplexs{?-η²-[（2-C₅H₄N）CH₂-C（O）（R₁）（R₂）]}₂Ru₂（CO）₄[R₁=CH₃;R₂=Ph（2i）]and three kinds of mononuclear ruthenium carbonyl complexs{?-η²-[（2-C₅H₄N）CH=C（O）（C₆H₄-4-R）]}₂Ru（CO）₂[R=Br（2c）;CF₃（2e）]{?-η²-[（2-C₅H₄N）CH=C（O）（C₆H₄-4-R）]}{?-η²-[（2-C₅H₄N）CH=C（C₆H₄-4-R）]}Ru（C O）₂[R=CF₃（2f）]were isolated.The composition and structure of complexes were characterized by elemental analysis,IR,¹H NMR and ¹³C NMR spectroscopy.The crystal structures of all complexes were determined by X-ray crystal diffraction analysis,indicating that structures of complexes 2a、2b、2d、2g、2h were similar,among 2a、2b、2d two ligands coordinated with two Ru atoms through three electrons donor olefinic alcohol?₂-O oxygen bridge,each pyridine N atom coordinated with one Ru atom,therefore chelating two six-membered ring,another Ru atom was linked together with four carbonyls.However,there was no olefinic alcohol?₂-O oxygen bridge in 2g、2h.（2）Catalytic activity of trinuclear ruthenium carbonyl complexs in aromatic alcohol and aliphatic alcohol oxidation reaction was investigated.The results indicated that the yield of complexs containing electron donating group was higher than that of electron-withdrawing.Furthermore,the yield of complexs in which substituent groups were in the opposite position was higher than that of adjacent.（3）The yield of aromatic alcohol（above 87%）was higher than aliphatic alcohol（above70%）.Moreover,yield of alcohols containing electron donating group>alcohols which has no substituents>alcohols containing electron-withdrawing.