Structure of suberic acid at 18.4, 75 and 123 K from neutron diffraction data

Gao, Qi; Weber, Hedda K.; Craven, B. M.; McMullan, R. K.

doi:10.1107/s0108768194003599

Cited by 29 publications

(20 citation statements)

References 10 publications

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“…No thermotropic phase transition has been reported so far, however, Terpstra et al (1993) and Kampermann et al (1995) demonstrated an intrinsic anharmonicity in the H atoms by re®ning the Gram±Charlier coef®cients (Johnson & Levy, 1974) from several X-ray and neutron diffraction measurements. Aliphatic dicarboxylic HOOC(CH 2 ) n À 2 COOH acids with 5 n 13 (Cn) crystallize in monoclinic space groups (Mortimer et al, 1958;Housty & Hospital, 1964, 1965a,b, 1966a,b,c, 1967Sintes et al, 1966;Housty, 1968;Haget et al, 1980;Gao et al, 1994;Bond et al, 2001a,b). The Cn structures show hydrogen-bonded arrangements forming ribbons extended throughout the crystal.…”

Section: Introductionmentioning

confidence: 99%

Structural changes of hexamethylenetetramine and undecanedioic acid co-crystal (HMT-C11) as a function of the temperature

Pinheiro

Gardon

Chapuis

2003

Acta Crystallogr Sect B

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HMT-C11 belongs to the family of adducts formed by the co-crystallization of N4(CH2)6 molecules (hexamethylenetetramine or HMT) and aliphatic dicarboxylic acids HOOC(CH2) n − 2COOH with 5 ≤ n ≤ 13 (Cn). The adducts exhibit a layered structure in which the packing between HMT and Cn is determined by strong hydrogen bonds. The compounds in this family studied so far present thermotropic structural phase transitions and, depending on the chain length, disordered, twinned and modulated phases. The structure refinement of HMT-C11 based on X-ray diffraction experiments indicates three distinct phases from the melting point down to liquid nitrogen temperature: phase I is not crystalline; phase II is disordered (stacking fault) and its average structure is described in space group Bmmb; phase III is partially disordered and its symmetry is P21/c. The systematic study of the structure evolution of phase III upon cooling revealed that the disorder has a dynamic character (anharmonicity). The main structural change observed from 293 K down to 93 K is the increase of the tilting angle of the C11 chains relative to the layer plane and the rotation of the HMT molecules. Both HMT and C11 behave like rigid bodies in the temperature range investigated. The quality of the refinements leads to a conclusive model for the O—H...N hydrogen bonds linking HMT and C11.

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Section: Introductionmentioning

confidence: 99%

Structural changes of hexamethylenetetramine and undecanedioic acid co-crystal (HMT-C11) as a function of the temperature

Pinheiro

Gardon

Chapuis

2003

Acta Crystallogr Sect B

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“…Suberic acid (COOH(CH 2 ) 6 COOH) is a fatty acid whose crystal structures were experimentally obtained at six different temperatures [20,21]. The starting structure for the MD simulation is shown in Fig.…”

Section: Methods and Modelmentioning

confidence: 99%

Molecular Dynamics Simulation of Hexamine and Suberic Acid

Pan

Brown

Chapuis

2003

Molecular Simulation

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In order to perform a molecular dynamics (MD) simulation of the incommensurate crystalline structure hexamethylenetetramine suberate (C 6 H 12 N 4 )(HOOC -(CH 2 ) 6 -COOH), we present in a first step the separate simulations of the crystalline structure of each of the two pure components, hexamethylenetetramine (HMT) and suberic acid. The domain decomposition parallel MD program ddgmq is used for this purpose. A secondgeneration consistent force field (CFF91) is employed to describe the interactions between atoms. Starting from experimental crystal structures, both pure components were heated from low to high temperatures. Our MD results show that the HMT system can be well represented by CFF91. In the case of suberic acid the layered structure of the crystal is largely preserved although deviations in the unit cell lengths from the experimental values are ,10%. Rather than attempt a complex re-parametrisation of CFF91 we chose to impose a fixed compensating external pressure tensor to correct for the deficiencies of the chosen force field. After optimising this compensating external pressure tensor at one temperature we find that experimental lattice constants and angles can be well reproduced over a range of temperatures.

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“…The following reflection conditions were observed: 0k00, k --2n, and hOlm, m = 2n, with the monoclinic axis b. Housty & Hospital, 1965;Gao, Weber & Craven, 1994). C, pp.…”

Section: Methodsmentioning

confidence: 99%

Hexamethylenetetramine suberate, a strongly anharmonic modulated structure

Gaillard¹,

Paciorek²,

Schenk³

et al. 1996

Acta Crystallogr Sect B

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Hexamethylenetetramine suberate is an organic compound presenting a one-dimensional modulation with strong satellite reflections between 123 and 300K. Single-crystal X-ray intensities of main reflections and satellites up to fourth order have been measured and used for refining a model based on displacive atomic modulation functions. Harmonic terms up to eighth order were necessary to describe the strongly anharmonic modulation. The structure consists of alternating sheets of hexamethylenetetramine and suberic acid connected by hydrogen bonds. Each layer of suberic acid chains consists of alternating areas, each of which is characterized by a common orientation for all chains. These orientations subtend an angle of roughly 60 ° . At the interfaces, neighbouring chains in adjacent areas adopt intermediate orientations. The two carboxyl groups participate in hydrogen bonds, the character of which depends on the internal coordinate t. In one group and for all values of t, the same oxygen forms a double bond with the o~-carbon and the other a single bond, and in the other the carboxylate form is observed for all values of t. The packings of both moieties are incompatible and are conjectured to be responsible for the incommensurability of the structure. Acta Cr3,stallographica Section B

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Structure of suberic acid at 18.4, 75 and 123 K from neutron diffraction data

Cited by 29 publications

References 10 publications

Structural changes of hexamethylenetetramine and undecanedioic acid co-crystal (HMT-C11) as a function of the temperature

Structural changes of hexamethylenetetramine and undecanedioic acid co-crystal (HMT-C11) as a function of the temperature

Molecular Dynamics Simulation of Hexamine and Suberic Acid

Hexamethylenetetramine suberate, a strongly anharmonic modulated structure

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