Topography of cyclodextrin inclusion complexes. XII. Hydrogen bonding in the crystal structure of α-cyclodextrin hexahydrate: the use of a multicounter detector in neutron diffraction

Klar, B.; Hingerty, Brian E.; Saenger, Wolfram

doi:10.1107/s0567740880005481

Cited by 123 publications

(43 citation statements)

References 14 publications

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“…These data are given in Table 3 and have been discussed in detail in the previous publications (Manor & Saenger, 1974;Klar, Hingerty & Saenger, 1980). It is noteworthy that the average data for bond lengths and angles for the two crystal structures, the highprecision form (I) and form (II), are comparable within the a limits.…”

Section: (C) Bond Distances and Anglessupporting

confidence: 52%

“…6H20 ) was reported (Manor & Saenger, 1972. As this investigation did not show all H-atom positions, a more recent neutron diffraction study, combined with new, improved X-ray data, was carried out from which all H atoms could be located (Klar et al, 1980). When batches were set up to grow single crystals big enough for neutron data collection, one of the batches did not show the usual stout, prismatic a-CD.6H20 crystals but rather tabular, flaky specimens.…”

Section: Introductionmentioning

confidence: 99%

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Topography of cyclodextrin inclusion complexes. XVI. Cyclic system of hydrogen bonds: structure of α-cyclodextrin hexahydrate, form (II): comparison with form (I)

Lindner¹,

Saenger²

1982

Acta Crystallogr B Struct Sci

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Section: (C) Bond Distances and Anglessupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Topography of cyclodextrin inclusion complexes. XVI. Cyclic system of hydrogen bonds: structure of α-cyclodextrin hexahydrate, form (II): comparison with form (I)

Lindner¹,

Saenger²

1982

Acta Crystallogr B Struct Sci

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“…The CD macrocycles are arranged in a typical herringbone-type pattern in the crystal environment (space group P2 1 2 1 2 1 , views along the a and b axis are given in Fig. 2), as is, for example, also found in the three a-CD hydrate solid-state structures [7][8][9].…”

Section: Resultsmentioning

confidence: 83%

Topography of the 1:1 α-cyclodextrin–nitromethane inclusion complex

Nakagawa

Immel

Lichtenthaler

et al. 2000

Carbohydrate Research

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Dissolution of a-cyclodextrin (a-CD) in 9:1 water-nitromethane smoothly generates the title compound, which crystallizes as the pentahydrate in the orthorhombic space group P2 1 2 1 2 1 with a = 9.452(4), b = 14.299(3), c= 37.380(10) A , , and Z= 4. Its crystal structure analysis revealed the a-CD macrocycle in an unstrained conformation stabilized through a ring of O-2···O-3% hydrogen bonds between five of the six adjacent glucose residues. The nitromethane is located in the a-CD cavity in an orientation parallel to the plane of the macrocycle, and assumes two sites of equal population with the nitro group in excessive thermal motion; the guest is held by van der Waals contacts and C-H···O-type hydrogen bonds to the pyranose H-3 and H-5 protons. The packing of the macrocycles in the crystal lattice is of cage herringbone-type with an extensive intra-and intermolecular hydrogen bonding network. The ready formation of a nitromethane inclusion complex in aqueous nitromethane, and the subtleties of its molecular structure amply demonstrate the ease with which water is expelled from the a-CD cavity by a more hydrophobic co-solvent.

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“…Moreover, by using the same force field in structure refinement as when generating 'observed' structure-factor amplitudes, the influence of the force field on the test of the time-averaging methodology is minimized. The crystal structure of a-cyclodextrin with six water molecules (Klar, Hingerty & Saenger, 1980) was used as the initial structure for the molecular system. This structure is in the orthorhombic space group P212~2~ with the unit-cell dimensions a--14.858, b=34.038, c--9.529 A.…”

Section: Generating Artificial Datamentioning

confidence: 99%

Time-averaging crystallographic refinement: possibilities and limitations using α-cyclodextrin as a test system

Schiffer¹,

Gros²,

Gunsteren³

1995

Acta Cryst D

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The method of time-averaging crystallographic refinement is assessed using a small molecule, a-cyclodextrin, as a test system. A total of 16 refinements are performed on simulated data. Three resolution ranges of the data are used, the memory relaxation time of the averaging is varied, and several overall temperature factors are used. The most critical factor in the reliable application of timeaveraging is the resolution of the data. The ratio of data to molecular degrees of freedom should be large enough to avoid overfitting of the data by the timeaveraging procedure. The use of a free R factor can aid in determining whether time-averaging can be reliably applied. Good ensembles of structures are obtained using data up to 1.0 or 2.0 A resolution. Comparison of electron-density maps from timeaveraging refinement and anisotropic temperaturefactor refinement indicates that the former technique yields a better representation of the exact data than the latter.

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Topography of cyclodextrin inclusion complexes. XII. Hydrogen bonding in the crystal structure of α-cyclodextrin hexahydrate: the use of a multicounter detector in neutron diffraction

Cited by 123 publications

References 14 publications

Topography of cyclodextrin inclusion complexes. XVI. Cyclic system of hydrogen bonds: structure of α-cyclodextrin hexahydrate, form (II): comparison with form (I)

Topography of cyclodextrin inclusion complexes. XVI. Cyclic system of hydrogen bonds: structure of α-cyclodextrin hexahydrate, form (II): comparison with form (I)

Topography of the 1:1 α-cyclodextrin–nitromethane inclusion complex

Time-averaging crystallographic refinement: possibilities and limitations using α-cyclodextrin as a test system

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