On the solid-state conformations of 18-crown-6 complexes

Fyles, Thomas M.; Gandour, Richard D.

doi:10.1007/bf01053871

Cited by 29 publications

(26 citation statements)

References 26 publications

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“…The structures are illustrated in three ways (Figs. 1-7): a structure with all atoms, a skeletal drawing of all donors to the cation, and a polar-coordinate map of the macrocyclic torsion angles (18). Endocyclic torsion angles are determined with the convention that a positive torsion angle exhibits a clockwise rotation between the front and the rear three atom planes.…”

Section: Resultsmentioning

confidence: 99%

Solid-state chemistry of polycarboxylate crown ether cation complexes: cooperative binding of water and metal ions by flexible chorands

Dutton¹,

Fyles²,

Suresh³

et al. 1993

Can. J. Chem.

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The solid-state structures of alkali-metal salt complexes of crown ether tetra-and hexa-carboxylic acids (18C6A4 and 18C6A6) have been determined. The sodium salt of 18C6A6 crystallizes as the trihydrate in orthorhombic space group P2,2,2, (a = 7.6868(12), b = 15.429(3), c = 21.975(2) A, R = 0.031 for 5192 observed data); the potassium salt of 18C6A6 crystallizes as the the trihydrate in orthorhombic space group P2,2,2, (a = 7.671 1(8), b = 15.709(2), c = 21.966(5) A, R = 0.035 for 2521 observed data); the thallium(1) salt of 18C6A6~rystallizes as the dihydrate in orthorhombic space group P2,2,2, (a = 12.0331(10), b = 12.4333(12), c = 17.366(2) A, R = 0.035 for 4952 observed data); and the cesium salt of 18C6& crystallizes as the dihydrate in monoclinic space group P2, (a = 7.708(3), b = 13.492(2), c = 11.9501(9) A, P = 94.49(2)", R = 0.029 for 4480 observed data). The sodium salt of 18S6A4 crystallizes as the dihydrate in monoclinic space group P2, (a = 11.4368(1 I), b = 7.7068(1 l), c = 12.6579(12) A, P = 98.515(8)", R = 0.035 for 3000 observed data); the thallium(1) salt ofo18C6A4 crystallizes as the dihydrate in monoclinic space group P2,(a = 11.719(2), b = 7.668(2), c = 12.8403(13) A, P = 99.052(9)", R = 0.040 for 3981 observed data); and the cesium saltoof 18C6A4 crystallizes as the dihydrate in monoclinic space group P2, (a = 11.787(2), b = 7.637(2), c = 13.001(2) A, p = 98.705(12)", R = 0.038 for 3428 observed data). Both chorands exhibit a cooperative relationship of mean cavity radius and guest-ion radius, which closely follows the effective ionic radii of the guests. The hexaacid is a preorganized host for monohydrated cations. It provides a trigonal hydrogen bonding receptor site for the water molecule, and up to nine oxygen donors for cation binding. Guests ranging in size from ~a ' to CS' are accommodated without distortion of the macrocyclic framework. The tetraacid is similarly tolerant of a range of guests, but greater structural reorganization of the ligand is required to optimize contacts with fully dehydrated cations. Skeletal drawings of donor atoms, in conjunction with polar coordinate maps of torsion angles, reveal how the demands of the guest are accommodated by the host. (2) A, p = 98,705(12)" et R = 0,038 pour 3428 donnees observees. Les deux chorands presentent une relation cooperative des rayons moyens de cavite et d'ion invite qui suit de trks prks celle des rayons ioniques effectifs des invites. L'hexaacide est un hBte preorganise pour les cations monohydrates. I1 fournit aux molCcules d'eau un site recepteur pour une liaison hydrogkne trigonale et jusqu'a neuf oxygenes donneurs pour des liaisons avec les cations. Les invites dont la taille se situe entre celles du Na' et du Cs+ s'accommodent sans distorsions dans la structure macrocyclique. Le tetraacide tolere aussi une grande variCtC d'invites; toutefois, une plus grande reorganisation structurale est requise du ligand pour optimiser les contacts avec les cations complktement deshydrates. Des diagrammes du squelette des atomes d...

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Section: Resultsmentioning

confidence: 99%

Solid-state chemistry of polycarboxylate crown ether cation complexes: cooperative binding of water and metal ions by flexible chorands

Dutton¹,

Fyles²,

Suresh³

et al. 1993

Can. J. Chem.

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“…The existence of 7r interactions between the Cs and the three terminal atoms of the two closest benzene rings can be inferred from the rather short contacts, ran~ing from 3.273 (5) to 3.770 (5),~, [mean value 3.6 (2)A]; this was also observed in the previous structures and is in agreement with NMR experiments . Using the notation proposed for the characterization of crown-ether conformations (Fyles & Gandour, 1992), the conformation of the ether chain was g+g-g+g-g+ (where g indicates a gauche O----C--C---O angle) in the previous isostructural complexes of 1,3-calix[4]-bis-crown-6. In the present case, the conformation is described by the sequence g+g-g+g+g-.…”

Section: Commentmentioning

confidence: 99%

Caesium Iodide Complex of 1,3-Calix[4]-bis-crown-6

Thuéry¹,

Nierlich²,

Lamare³

et al. 1996

Acta Crystallogr C

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“…The macrocycle adopts a distorted g -g + g + gg+g+ conformation, one of the six sequences which commonly occurs in solid-state 18-crown-6 complexes (Fyles & Gandour, 1992)…”

Section: Commentmentioning

confidence: 99%