title: Role of the reaction intermediates in determining PHIP (parahydrogen induced polarization) effect in the hydrogenation of acetylene dicarboxylic acid with the complex [Rh (dppb)]+ (dppb: 1,4-bis(diphenylphosphino)butane).
abstract: This study deals with the parahydrogenation of the symmetric substrate acetylene dicarboxylic acid catalyzed by a Rh(I) complex bearing the chelating diphosphine dppb (1,4-bis(diphenylphosphino)butane). The two magnetically equivalent protons of the product yield a hyperpolarized emission signal in the (1)H-NMR spectrum. Their polarization intensity varies upon changing the reaction solvent from methanol to acetone. A detailed analysis of the hydrogenation pathway is carried out by means of density functional theory calculations to assess the structure of hydrogenation intermediates and their stability in the two solvents. The observed polarization effects have been accounted on the basis of the obtained structures. Insights into the lifetime of a short-lived reaction intermediate are also obtained.
authors.affiliation: Department of Molecular Biotechnologies and Health Sciences, University of Torino, Via Nizza 52, 10123 Torino, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Reineri
authors.affiliation: Department of Molecular Biotechnologies and Health Sciences, University of Torino, Via Nizza 52, 10123 Torino, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Aime
authors.affiliation: Department of Chemistry, University of Torino, via P. Giuria 7, 10125 Torino, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Gobetto
authors.affiliation: Department of Chemistry, University of Torino, via P. Giuria 7, 10125 Torino, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Nervi
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D003998:Dicarboxylic Acids / Q000737:chemistry*; D006865:Hydrogenation; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D011789:Quantum Theory; D012238:Rhodium / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D003998:Dicarboxylic Acids; D009942:Organometallic Compounds; D012238:Rhodium; D000114:Acetylene