Me. Sobhia et al., CRYSTAL-STRUCTURE OF AN UNCOMPLEXED 25-CROWN-7 COMPRISING ONE 2,6-PYRIDINO AND 2 1,4-BENZO CONDENSATIONS, Journal of inclusion phenomena and molecular recognition in chemistry, 18(1), 1994, pp. 1-8
Single crystal X-ray analysis of the uncomplexed crown macroring 1 is
reported. Crystals are triclinic, P $($) over bar$$ 1, with a = 10.809
(1), b = 10.945(1), c = 10.256(1) Angstrom, alpha = 107.85(1), beta =
104.15(1), gamma = 87.27(1)degrees, D-c = 1.318 g cm(-3), Z = 2. Three
torsion angles in the macrocycle take up gauche conformations in cont
rast to the usual anti conformation. The crystal structure is stabiliz
ed by intramolecular van der Waals forces and weak C-H...O and C-H...N
hydrogen bond attractions. Stacking of pyridine rings is a noticeable
packing feature in the crystal lattice.