Absorbing a Little Water: The Structural, Thermodynamic, and Kinetic Relationship between Pyrogallol and Its Tetarto-Hydrate

Abstract

The anhydrate and the stoichiometric tetarto-hydrate of pyrogallol (0.25 mol water per mol pyrogallol) are both storage stable at ambient conditions, provided that they are phase pure, with the system being at equilibrium at aw (water activity) = 0.15 at 25 °C. Structures have been derived from single crystal and powder X-ray diffraction data for the anhydrate and hydrate, respectively. It is notable that the tetarto-hydrate forms a tetragonal structure with water in channels, a framework that although stabilized by water, is found as a higher energy structure on a computationally generated crystal energy landscape, which has the anhydrate crystal structure as the most stable form. Thus, a combination of slurry experiments, X-ray diffraction, spectroscopy, moisture (de)sorption, and thermo-analytical methods with the computationally generated crystal energy landscape and lattice energy calculations provides a consistent picture of the finely balanced hydration behavior of pyrogallol. In addition, two monotropically related dimethyl sulfoxide monosolvates were found in the accompanying solid form screen.

Quantitative analysis of intermolecular interactions in orthorhombic rubrene

“…Calculation of lattice energy and interaction energies of molecular dimers using the PIXEL (Gavezzotti, 2011) method enables partitioning of the total energy into electrostatic, polarization, dispersion and repulsion components. The values obtained from the PIXEL calculations are known to be comparable to high level MP2 and DFT-D quantum mechanical calculations (Gavezzotti, 2008;Dunitz & Gavezzotti, 2012;Maschio et al, 2011;Braun et al, 2013). The different energy contributions reveal that a significant amount of the total lattice energy comes from the dispersion interactions (E disp ' 5.6E es ' 9.1E pol , Table 2).…”

Diversity of crystal structures and physicochemical properties of ciprofloxacin and norfloxacin salts with fumaric acid

“…[35][36][37] At constant temperature, the formation of the hydrated form from anhydrous crystals may be represented by the following equilibrium:…”

Accurate and efficient representation of intramolecular energy inab initiogeneration of crystal structures. I. Adaptive local approximate models

“…This paper focuses on significantly improving the efficiency of the global search stage via improvements to the Crystal-Predictor algorithm (Karamertzanis & Pantelides, 2007, 2005Habgood et al, 2015), which has been used extensively in blind tests and in a variety of CSP applications (see, for example, Bardwell et al, 2011;Day et al, 2009;Braun et al, 2013Braun et al, , 2014Braun et al, , 2016Vasileiadis et al, 2012;Eddleston et al, 2015;Uzoh et al, 2012).…”