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Conformational studies of dibenzo-30-crown-10 complexes. Syntheses and crystal structures of potassium and ammonium hexafluorophosphate complexes

Crown ether complexes formed by the dibenzo-30-crown-10 (DB30C10) with potassium and ammonium hexafluorophosphate have been prepared and their crystal structures have been determined by single crystal X-ray analyses. The potassium complex (compound 1) consists of [K(DB30C10)](+) cation and PF6(-) anion. Crystals are monoclinic, space group P2/n, with a = 11.9106(3), b = 9.8382(5), c = 14.3062(3) Angstrom, beta = 97.581(3)degrees, V = 1661.7(1) Angstrom(3), Dc = 1.440 g cm(-3), Z = 4, R = 0.0675 for 2528 unique observed reflections. The potassium ion is coordinated to ten oxygen atoms of the crown ligand at the distance from 2.859(3) to 2.930(3) Angstrom. The ammonium complex (compound 2) has also 1:1 crown – cation ratio. Crystals are monoclinic, spece group P21/n, with a = 12.5061(6), b = 19.3724(5), c = 14.2203(9) Angstrom, beta = 102.476(5)degrees, V = 3363.8(3) Angstrom(3), Dc = 1.501 g cm(-3), Z = 4, R = 0.0677 for 4172 unique observed reflections. The ammonium cation is completely enclosed with crown oxygen atoms forming seven hydrogen bonds. The conformation of previously reported dibenzo-30-crown-10 complexes with potassium salts were investigated using polar coordinate maps.

dibenzo-30-crown-10 complexes; crystal structure; conformation; molecular recognation; hydrogen bonding

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