An experimental charge density study of aliphatic dicarboxylic acids

Gopalan, R.; Kumaradhas, Poomani; Kulkarni, Giridhar U.; Rao, C. N. R.

doi:10.1016/s0022-2860(99)00293-8

Cited by 73 publications

(30 citation statements)

References 20 publications

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“…56 In the crystal structures of the S-enantiomer and racemic compounds RSI and RSII, malic acid molecules form chains with neighbour molecules in the chains being linked by hydrogen bonds. [57][58][59][60] This is a common arrangement for dicarboxylic acids, such as terephthalic, 61 succinic 62 and adipic 62 acids.…”

Section: The System (S)-malic Acid-(r)-malic Acidmentioning

confidence: 99%

Non-equimolar discrete compounds in binary chiral systems of organic substances

2017

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Section: The System (S)-malic Acid-(r)-malic Acidmentioning

confidence: 99%

Non-equimolar discrete compounds in binary chiral systems of organic substances

2017

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“…At ambient conditions, the only crystal structure known for malonic acid for almost half a century was that determined from photographic data (Goedkoop & MacGillavry, 1957). Recently a more precise, low-temperature (130-145 K) charge-density study of the lower carboxylic acids (n = 2-5), including malonic acid (Srinivasa Gopalan et al, 2000), confirmed the essential correctness of the phase. At ambient temperature and all the way down to thetransition, the crystal structure of malonic acid is triclinic (Z = 2), while all other members of the higher carboxylic acid series assume monoclinic symmetry at ambient temperature ( Table 1).…”

Section: Introductionmentioning

confidence: 99%

Deuterated γ-malonic acid: its neutron crystal structure in relationship to other polymorphs of aliphatic dicarboxylic acids

McMullan

Klooster

Weber³

2008

Acta Crystallogr Sect B

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Three complete neutron diffraction datasets have been collected for deuterated malonic acid single crystals, DOOC(CD(2))COOD, above (153 K), just below (56 K) and further below (50 K) the low-temperature phase transition (T(c) = 57 K). The structural details obtained for this transition, studied previously solely by spectroscopic and calorimetric techniques, clearly establish its first-order nature. At 153 K, the space group is P\bar 1, Z = 2, Z' = 1. The molecules are packed as linear chains linked end-to-end by asymmetric hydrogen bonds so that the carboxyl groups form cyclic dimers. The deuterons in the carboxyl links are ordered. Neighboring chains are cross-linked through C-D...O hydrogen bonds. Upon cooling through the transition the cell doubles along the a axis. Molecules which are equivalent by symmetry above T(c) become independent below T(c) owing to conformational changes in alternate chains. At 50 K, the space group is P\bar 1, Z = 4, Z' = 2. Thermal motion analysis, using for all three temperatures the same segmented rigid-body model, reveals a large torsional motion around the one COOD group associated with the conformational change. Refinements were carried out on all three datasets with an anharmonic structural model, including higher-order displacement tensors (Gram-Charlier expansion up to fourth order). Only atoms involved in torsional motion exhibit a significant anharmonic component which increases with temperature.

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“…It can also be due to shape/size mismatch between the interacting components, thus preventing NCT molecule to build any new supramolecular network with the drug. Similarly, crystal data of MA reported robust acid–acid dimers (OH….O) synthon forming

R_{2}^{2}

(8) ring motif . However, the heteromeric interaction between MA and FEL is not strong enough to replace homomeric interactions (drug–drug and coformer–coformer) and is ineffective in the transformation of the crystal packing of individual components and results into eutectic binary mixtures.…”

Section: Resultsmentioning

confidence: 99%

“…..O) synthon forming R 2 2 (8) ring motif. [22] However, the heteromeric interaction between MA and FEL is not strong enough to replace homomeric interactions (drug-drug and coformer-coformer) and is ineffective in the transformation of the crystal packing of individual components and results into eutectic binary mixtures.…”

Section: Felodipine-nicotinamide and Felodipinemalonic Acid Eutecticsmentioning

confidence: 99%