ja211220r_si_004.cif (31.42 kB)
Isolation of (CO)1– and (CO2)1– Radical Complexes of Rare Earths via Ln(NR2)3/K Reduction and [K2(18-crown-6)2]2+ Oligomerization
dataset
posted on 2016-02-21, 14:51 authored by Ming Fang, Joy H. Farnaby, Joseph W. Ziller, Jefferson
E. Bates, Filipp Furche, William J. EvansDeep-blue solutions of Y2+ formed from Y(NR2)3 (R = SiMe3) and excess potassium
in the
presence of 18-crown-6 at −45 °C under vacuum in diethyl
ether react with CO at −78 °C to form colorless crystals
of the (CO)1– radical complex, {[(R2N)3Y(μ-CO)2][K2(18-crown-6)2]}n, 1. The polymeric structure
contains trigonal bipyramidal [(R2N)3Y(μ-CO)2]2– units with axial (CO)1– ligands linked by [K2(18-crown-6)2]2+ dications. Byproducts such as the ynediolate, [(R2N)3Y]2(μ-OCCO){[K(18-crown-6)]2(18-crown-6)}, 2, in which two (CO)1– anions are coupled to form (OCCO)2–, and
the insertion/rearrangement product, {(R2N)2Y[OC(CH2)Si(Me2)NSiMe3]}[K(18-crown-6)], 3, are common in these reactions that give variable results
depending on the specific reaction conditions. The CO reduction in
the presence of THF forms a solvated variant of 2, the
ynediolate [(R2N)3Y]2(μ-OCCO)[K(18-crown-6)(THF)2]2, 2a. CO2 reacts analogously
with Y2+ to form the (CO2)1– radical complex, {[(R2N)3Y(μ-CO2)2][K2(18-crown-6)2]}n, 4, that has a structure similar
to that of 1. Analogous (CO)1– and
(OCCO)2– complexes of lutetium were isolated
using Lu(NR2)3/K/18-crown-6: {[(R2N)3Lu(μ-CO)2][K2(18-crown-6)2]}n, 5, [(R2N)3Lu]2(μ-OCCO){[K(18-crown-6)]2(18-crown-6)}, 6, and [(R2N)3Lu]2(μ-OCCO)[K(18-crown-6)(Et2O)2]2, 6a.
