Effect of Solvent Topography and Steric Hindrance on Crystal Morphology

Abstract

Effect of steric hindrance resulting from solvent topography on the resultant crystal morphology was examined via cooling crystallization of various carboxylic acids in isomeric butyl and pentyl alcohols. Our experiments show that the magnitude of hindrance is related to the degree of branching at the substituted carbon, with hindrance increasing in the order of 1° < 2° < 3° alcohols. The resulting crystals displayed a trend of low, intermediate, and high aspect ratios, corresponding to 1°, 2°, and 3° alcohols, respectively. In particular, 3° alcohols have a tendency to yield significantly different crystal morphologies, compared to 1° and 2° alcohols. Hence, the position of the hydroxyl functional group plays a major role in enhancing or limiting solute–solvent hydrogen bonding interactions and thereby influencing the resultant crystal morphology. A simple molecular model, with succinic acid as test case, was used to demonstrate the extended hydrogen bonding network and surface chemistry binding at the dominant {100} face. This molecular-level exploration of solvent–carboxyl hydrogen bonding interaction at the crystal interface helped explain observed macroscopic morphological trends.

Tuning Crystal Morphology of Succinic Acid Using a Polymer Additive

“…Face indexing was used to identify the crystal faces involved in the morphology change (Figure 9): the faces identified for the plate-like crystals produced in the presence of no polymer correspond to those previously reported. 54,61 As discussed in previous literature, 62,66 in the crystal structure of β-succinic acid, the (100) face intercepts chains of succinic acid molecules linked by hydrogen bonded carboxylic acid dimers (Figure 10). This makes the (100) face a polar face with which water molecules would be likely to interact, inhibiting growth along the direction perpendicular to this face and suggesting why it is the largest face in crystallizations carried out from water.…”

Energy Decomposition Analysis Based on Absolutely Localized Molecular Orbitals for Large-Scale Density Functional Theory Calculations in Drug Design

“…For the benzene -ammonium system, re-initialisation to guess NGWFs at the polarisation stage was required in order to prevent under-convergence of the polarisation energy component. 2 Grimme -D3 correction results are also included for comparison in Section SI.4 of the Supporting Information. The -D3 contributions were calculated using the DFT-D3 program as only the -D2 correction is currently implemented in ONETEP.…”

“…Intermolecular interactions are of key importance in determining the physical and chemical properties of molecular systems. For example, the intermolecular forces that govern a hydrogen bond are of great interest to chemists due to the role they play in determining polymeric structures and macroscopic properties of structures. , The effect of σ holes as observed in a number of halogen-bonding complexes has implications for drug–host binding, and therefore, this interaction is of key pharmaceutical interest. Scientific fields that involve the study of systems containing large numbers of intermolecular interactions, such as the disciplines of biomolecular , and supramolecular chemistry , and condensed matter physics, , benefit from the insights gained from studies of intermolecular bonding.…”

Liquid–Liquid Equilibrium for Ternary Systems of 2-Pentanone/Mesityl Oxide + Catechol + Water at 298.2, 318.2, and 333.2 K

“…Several solvents, such as methyl isobutyl ketone, − n -butyl acetate, methyl isopropyl ketone, and methyl butyl ketone, have been researched to extract dihydric phenols from wastewater recently. However, the carbon chain of methyl isobutyl ketone and methyl isopropyl ketone have a “–CH 3 ” branched chain, which produces the steric hindrance effects for intermolecular hydrogen bonding between solvent and dihydric phenols. − The functional group of n -butyl acetate cannot produce hydrogen bonding with phenolic hydroxyls directly and needs water as the middle bridge. Therefore, n -butyl acetate has a lower distribution coefficient for dihydric phenols.…”