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

作者：Prack Ernest; O'Keefe Christopher A; Moore Jeremy K; Lai Angel; Lough Alan J; Macdonald Peter M; Conradi Mark S; Schurko Robert W^*; Fekl Ulrich

来源：Journal of the American Chemical Society, 2015, 137(42): 13464-13467.

DOI：10.1021/jacs.5b08213

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((PBu3)-Bu-t)(2) was experimentally studied by H-2 and Pt-195 solid-state NMR spectroscopy (powder pattern changes with temperature) and computationally modeled as a (Bu3P)-Bu-t-Pt-(PBu3)-Bu-t stator with a spinning H-Pt-H rotator. Whereas the related chloro-hydride complex, trans-H(Cl)-Pt((PBu3)-Bu-t)(2), does not show rotational behavior at room temperature, the dihydride trans-H2Pt((PBu3)-Bu-t)(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 similar to 3 kcal mol(-1), for the roughly 3 angstrom long rotator in trans-H2Pt((PBu3)-Bu-t)(2).

• 出版日期2015-10-28