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Download fileStructural Aspects of Rubidium Ion Selectivity by Tribenzo-21-crown-71a
dataset
posted on 1998-05-07, 00:00 authored by Jeffrey C. Bryan, Richard A. Sachleben, Jérôme M. Lavis, Matthew C. Davis, John H. Burns, Benjamin P. HayThe structural origins of the selectivity of rubidium ion over
other alkali metal ions by tribenzo-21-crown-7 is
investigated from single-crystal X-ray diffraction: data for
Cs(tribenzo-21-crown-7)(NO3), monoclinic,
P21/c, a
= 9.598(2) Å, b = 23.466(3) Å, c
= 23.973(5) Å, β = 93.31(1)°, V =
5390(2) Å3, Z = 8; data for
[Rb(4,4‘-bis-tert-butylbenzo,benzo-21-crown-7)(dioxane)1.5(H2O)0.18][Cl]·(dioxane)1.82(H2O),
triclinic, P1̄, a = 11.687(3)
Å, b = 12.800(4) Å, c = 17.680(3)
Å, α = 75.31(2)°, β = 80.01(2)°, γ =
69.09(2)°, V = 2379.8(10) Å3,
Z =
2; data for
Na(4,4‘-bis-tert-butylbenzo,benzo-21-crown-7)ReO4·0.5(i-PrOH),
monoclinic, P21/c, a =
24.300(5)
Å, b = 14.066(3) Å, c = 22.676(5)
Å, β = 108.06(3)°, V = 7369(3)
Å3, Z = 8; data for and
4,4‘-bis-tert-butylbenzo,benzo-21-crown-7, monoclinic,
P21/n, a =
16.427(2) Å, b = 11.3675(9) Å, c
= 33.137(3) Å, β =
94.469(8)°, V = 6169.0(10) Å3,
Z = 8. The structures reported here are the first
reported for a tribenzo-21-crown-7, and the alkali metal ion complexes are the first reported
structures of these ions with any 21-crown-7
ether. Different crown conformations are observed for each
structure. Molecular mechanics calculations were
performed on all conformers, and the results are related to the
observed extraction selectivity for rubidium.