ja5b11508_si_002.cif (1.54 MB)
Expanding Thorium Hydride Chemistry Through Th2+, Including the Synthesis of a Mixed-Valent Th4+/Th3+ Hydride Complex
dataset
posted on 2016-03-15, 12:36 authored by Ryan R. Langeslay, Megan
E. Fieser, Joseph W. Ziller, Filipp Furche, William J. EvansThe
reactivity of the recently discovered Th2+ complex
[K(18-crown-6)(THF)2][Cp″3Th], 1 [Cp′′ = C5H3(SiMe3)2-1,3], with hydrogen reagents has been investigated
and found to provide syntheses of new classes of thorium hydride compounds.
Complex 1 reacts with [Et3NH][BPh4] to form the terminal Th4+ hydride complex Cp″3ThH, 2, a reaction that formally involves a net
two-electron reduction. Complex 1 also reacts in the
solid state and in solution with H2 to form a mixed-valent
bimetallic product, [K(18-crown-6)(Et2O)][Cp″2ThH2]2, 3, which was analyzed
by X-ray crystallography, electron paramagnetic resonance and optical
spectroscopy, and density functional theory. The existence of 3, which formally contains Th3+ and Th4+, suggested that KC8 could reduce [(C5Me5)2ThH2]2. In the presence
of 18-crown-6, this reaction forms an analogous mixed-valent product
formulated as [K(18-crown-6)(THF)][(C5Me5)2ThH2]2, 4. A similar complex
with (C5Me4H)1– ligands was
not obtained, but reaction of (C5Me4H)3Th with H2 in the presence of KC8 and 2.2.2-cryptand
at −45 °C produced two monometallic hydride products,
namely, (C5Me4H)3ThH, 5, and [K(2.2.2-cryptand)]{(C5Me4H)2[η1:η5-C5Me3H(CH2)]ThH]}, 6. Complex 6 contains
a metalated tetramethylcyclopentadienyl dianion, [C5Me3H(CH2)]2–, that binds in a tuck-in
mode.