title: A Molecular Rotor Possessing an H-M-H "Spoke" on a P-M-P "Axle": A Platinum(II) trans-Dihydride Spins Rapidly Even at 75 K.
abstract: A new class of low-barrier molecular rotors, metal trans-dihydrides, is suggested here. To test whether rapid rotation can be achieved, the known complex trans-H2Pt(P(t)Bu3)2 was experimentally studied by (2)H and (195)Pt solid-state NMR spectroscopy (powder pattern changes with temperature) and computationally modeled as a (t)Bu3P-Pt-P(t)Bu3 stator with a spinning H-Pt-H rotator. Whereas the related chloro-hydride complex, trans-H(Cl)Pt(P(t)Bu3)2, does not show rotational behavior at room temperature, the dihydride trans-H2Pt(P(t)Bu3)2 rotates fast on the NMR time scale, even at low temperatures down to at least 75 K. The highest barrier to rotation is estimated to be ∼3 kcal mol(-1), for the roughly 3 Å long rotator in trans-H2Pt(P(t)Bu3)2.
authors.affiliation: University of Toronto , Mississauga Campus, 3359 Mississauga Road, Mississauga, Ontario, Canada L5L 1C6.
authors.forename: Ernest
authors.initials: E
authors.lastname: Prack
authors.affiliation: University of Windsor , 401 Sunset Ave., Windsor, Ontario, Canada , N9B 3P4.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: O'Keefe
authors.affiliation: Washington University, St. Louis , One Brookings Drive, St. Louis, Missouri 63130-4899, United States.
authors.forename: Jeremy K
authors.initials: JK
authors.lastname: Moore
authors.affiliation: University of Toronto , Mississauga Campus, 3359 Mississauga Road, Mississauga, Ontario, Canada L5L 1C6.
authors.forename: Angel
authors.initials: A
authors.lastname: Lai
authors.affiliation: University of Toronto , St. George Campus, 80 St. George St., Toronto, Ontario, Canada M5S 3H6.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Lough
authors.affiliation: University of Toronto , Mississauga Campus, 3359 Mississauga Road, Mississauga, Ontario, Canada L5L 1C6.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Macdonald
authors.affiliation: Washington University, St. Louis , One Brookings Drive, St. Louis, Missouri 63130-4899, United States.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Conradi
authors.affiliation: University of Windsor , 401 Sunset Ave., Windsor, Ontario, Canada , N9B 3P4.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Schurko
authors.affiliation: University of Toronto , Mississauga Campus, 3359 Mississauga Road, Mississauga, Ontario, Canada L5L 1C6.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Fekl