TY - JOUR
T1 - Predicting cocrystallization based on heterodimer energies
T2 - The case of N,N′-diphenylureas and triphenylphosphine oxide
AU - Solomos, Marina A.
AU - Mohammadi, Cameron
AU - Urbelis, Jessica H.
AU - Koch, Elizabeth S.
AU - Osborne, Rochelle
AU - Usala, Claire C.
AU - Swift, Jennifer A.
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/10/7
Y1 - 2015/10/7
N2 - Diarylureas frequently assemble into structures with one-dimensional H-bonded chain motifs. Herein, we examine the ability of triphenylphosphine oxide (TPPO) to disrupt the H-bonding motif in 14 different meta-substituted N,N′-diphenylureas (mXPU) and form cocrystals; 1:1 mXPU:TPPO cocrystals were obtained in 9 of 14 cases examined (64% success rate). Cocrystals adopt five different lattice types, all of which show unsymmetrical H-bonded [R2 (6)] dimers between the urea hydrogens and the phosphine oxygen. Heterodimer (mXPU⋯TPPO) and homodimer (mXPU⋯mXPU) interaction energies, ΔEint, calculated using density functional theory at the B3LYP/6-31G(d,p) level were used to rationalize the experimental results. A clear trend was observed in which cocrystals were experimentally realized only in cases in which the differences in heterodimer versus homodimer energy, ΔΔEint, were greater than ∼5.3-6 kcal/mol. Although calculated interaction energies are a simplified measure of the system thermodynamics, these results suggest that the relative ΔΔEint between heterodimers and homodimers is a good predictor of cocrystal formation in this system.
AB - Diarylureas frequently assemble into structures with one-dimensional H-bonded chain motifs. Herein, we examine the ability of triphenylphosphine oxide (TPPO) to disrupt the H-bonding motif in 14 different meta-substituted N,N′-diphenylureas (mXPU) and form cocrystals; 1:1 mXPU:TPPO cocrystals were obtained in 9 of 14 cases examined (64% success rate). Cocrystals adopt five different lattice types, all of which show unsymmetrical H-bonded [R2 (6)] dimers between the urea hydrogens and the phosphine oxygen. Heterodimer (mXPU⋯TPPO) and homodimer (mXPU⋯mXPU) interaction energies, ΔEint, calculated using density functional theory at the B3LYP/6-31G(d,p) level were used to rationalize the experimental results. A clear trend was observed in which cocrystals were experimentally realized only in cases in which the differences in heterodimer versus homodimer energy, ΔΔEint, were greater than ∼5.3-6 kcal/mol. Although calculated interaction energies are a simplified measure of the system thermodynamics, these results suggest that the relative ΔΔEint between heterodimers and homodimers is a good predictor of cocrystal formation in this system.
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U2 - 10.1021/acs.cgd.5b01039
DO - 10.1021/acs.cgd.5b01039
M3 - Article
AN - SCOPUS:84943549036
SN - 1528-7483
VL - 15
SP - 5068
EP - 5074
JO - Crystal Growth and Design
JF - Crystal Growth and Design
IS - 10
ER -