title: Parahydrogen Induced Polarization with Rh-based Monodentate Ligand in Water.
abstract: Reported here is a water soluble Rh(I)-based catalyst for performing parahydrogen induced polarization (PHIP). The [Rh(I)(norbornadiene)(THP)(2)](+)[BF(4)](-) catalyst utilizes the monodentate phosphine ligand tris(hydroxymethyl)phosphine (THP). The monodentate PHIP catalyst is less susceptible to oxygenation by air and THP ligand and is significantly less expensive than bidentate water-soluble PHIP ligands. In situ PHIP detection with this monodentate Rh(I) based catalyst in water yielded 12% (13)C polarization for the parahydrogen addition product, 2-hydroxyethyl 1-(13)C-propionate-d(2,3,3) (HEP), with a (13)C T(1) relaxation of 108 seconds at 0.0475 T. PHIP polarization yields were high, reflecting efficient hydrogenation even under conditions of high content of the oxidized phosphine form of the THP ligand.
authors.affiliation: Vanderbilt University Institute of Imaging Science (VUIIS), Department of Radiology, Nashville, TN, 37232, United States.
authors.forename: Roman V
authors.initials: RV
authors.lastname: Shchepin
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Coffey
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Waddell
authors.forename: Eduard Y
authors.initials: EY
authors.lastname: Chekmenev