ISSN:
1573-1111
Keywords:
Bridged calixarene
;
inclusion compounds
;
pyridine complex
;
molecular mechanics
;
X-ray
;
macrobicyclic compounds
;
weak host-guest interactions
;
CH3-π interactions
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The crystal and molecular structure of a crownedp-t-butyl-calix[4]arene (1:1) pyridine complex is reported. Colourless transparent prismatic crystals (obtained from pyridine) C54H74O8·C5H5N,a=13.486(4),b=15.193(4),c=16.432(5) Å, β=116.44(4)°, space groupP21,Z=2,D calc=1.02g cm−3, CuK α radiation λ=1.5418 Å μ(CuK α)=4.99 cm−1. Refinement was carried out using 1702 reflections withI〉3σ(I) toR 0.12. The macrocycle shows a distorted cone conformation which defines an intramolecular apolar cavity whose elliptical aperture is 11.5×8.6 Å calculated as distances between the two opposite central C atoms of the Bu t groups. A molecule of pyridine is included in this cavity, whereas the intermolecular cavities of the host lattice remain empty. The influence of the guest molecule on the conformation of the calixarene-crown is discussed. Potential energy calculations are performed in order to understand the nature of the host-guest interactions responsible for the stabilisation of the complex. Evidence for stabilizing CH3-π interactions are obtained from the calculations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00660750
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