HYDROXCAT · Novel catalytic reactions involving O-H bonds

Our group has recently discovered novel reactions catalyzed by pyridine-based pincer complexes of ruthenium, including dehydrogenation of alcohols to form esters and H2, hydrogenation of esters to alcohols under mild conditions and an unprecedented amide synthesis: catalytic coupling of amines with alcohols, with liberation of H2 (Science, 2007, 317, 790; C&EN Aug 13, 2007, p. 10). The reactions are very efficient, proceed under neutral conditions and produce no waste. Our studies indicate that these reactions involve unprecedented cooperation between the metal and ligand by an aromatization-dearomatization of the pyridine core of the pincer system. We plan to (a) study the mechanism of the O-H activation step of alcohols by dearomatized PNP and PNN Ru complexes (d) develop mechanistic understanding of catalytic alcohol dehydrogenation to esters and catalytic amidation of alcohols with amines, and design superior pyridine-based pincer ligands for these reactions (e) prepare analogous iron complexes and study their reactivity and catalytic activity (f) develop new catalytic reactions based on alcohols, including dehydrogenative coupling reactions of aldehydes with alcohols, and aldehydes with amines, to form esters and amides, respectively, and anti-Markovnikov addition of water and to alkenes. This research is expected to lead to fundamental understanding of unprecedented organometallic transformations, and to novel, environmentally benign catalytic processes of industrial significance.