Limits...
Solvent inclusion in the crystal structure of bis ­ [(adamantan-1-yl)methanaminium chloride] 1,4-dioxane hemisolvate monohydrate explained using the computed crystal energy landscape

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Repeated attempts to crystallize 1-adamantane­methyl­amine hydro­chloride as an anhydrate failed but the salt was successfully crystallized as a solvate (2C11H20N+·2Cl−·0.5C4H8O2·H2O), with water and 1,4-dioxane playing a structural role in the crystal and engaging in hydrogen-bonding inter­actions with the cation and anion. Computational crystal-structure prediction was used to rationalize the solvent-inclusion behaviour of this salt by computing the solvent-accessible voids in the predicted low-energy structures for the anhydrate: the global lattice-energy minimum structure, which has the same packing of the ions as the solvate, has solvent-accessible voids that account for 3.71% of the total unit-cell volume and is 6 kJ mol−1 more stable than the next most stable predicted structure.

No MeSH data available.


Predicted crystal energy landscape of (adamantan-1-yl)methanaminium chloride. The lattice energy is plotted relative to the predicted global minimum structure for the salt. The data point labelled DesolvMinOpt corresponds to the theoretical lattice energy minimum structure that would result from desolvation of the experimental (adamantan-1-yl)methanaminium chloride 1,4-dioxane hydrate structure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5120722&req=5

fig3: Predicted crystal energy landscape of (adamantan-1-yl)methanaminium chloride. The lattice energy is plotted relative to the predicted global minimum structure for the salt. The data point labelled DesolvMinOpt corresponds to the theoretical lattice energy minimum structure that would result from desolvation of the experimental (adamantan-1-yl)methanaminium chloride 1,4-dioxane hydrate structure.

Mentions: The computed crystal energy landscape (Fig. 3 ▸) of 1-adamantane­methyl­amine hydro­chloride was used to assess the possibility of solvent inclusion for this salt by estimating the percentage solvent-accessible volume in the predicted most stable packings. The most stable structure on the crystal energy landscape of the anhydrate displays a total potential solvent-accessible volume of 45.6 Å3, which corresponds to 3.71% of the unit-cell volume. Assuming that each water mol­ecule occupies an approximate total volume of 40 Å3, this would suggest that the global minimum structure could be crystallized by dehydration of a monohydrate of the salt. The global lattice energy minimum structure is approximately 6 kJ mol−1 more stable than the nearest competing second-ranked structure. The observation of a clearly preferred global lattice energy minimum structure with solvent-accessible voids is not conclusive in suggesting that this hydro­chloride salt cannot be crystallized as an anhydrate, but it does suggest that this system will have difficulties crystallizing as an anhydrate since there is an energetic preference for a packing of the ions that is susceptible to solvent inclusion. Although the second-ranked most stable predicted structure does not have any solvent-accessible voids, this structure is energetically competitive with the third-ranked structure which displays an unusually large percentage solvent-accessible volume of 17.42% of the unit cell. The majority of the predicted structures within 10 kJ mol−1 of the global minimum structure that have solvent-accessible voids have crystal voids that are located within 4.5 Å of the charged N+/Cl− ions, which is consistent with the observation that both the water and 1,4-dioxane solvent mol­ecules in the experimental structure engage in hydrogen-bonding inter­actions with the N+—H donor and Cl− acceptor groups of the salt.


Solvent inclusion in the crystal structure of bis ­ [(adamantan-1-yl)methanaminium chloride] 1,4-dioxane hemisolvate monohydrate explained using the computed crystal energy landscape
Predicted crystal energy landscape of (adamantan-1-yl)methanaminium chloride. The lattice energy is plotted relative to the predicted global minimum structure for the salt. The data point labelled DesolvMinOpt corresponds to the theoretical lattice energy minimum structure that would result from desolvation of the experimental (adamantan-1-yl)methanaminium chloride 1,4-dioxane hydrate structure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120722&req=5

fig3: Predicted crystal energy landscape of (adamantan-1-yl)methanaminium chloride. The lattice energy is plotted relative to the predicted global minimum structure for the salt. The data point labelled DesolvMinOpt corresponds to the theoretical lattice energy minimum structure that would result from desolvation of the experimental (adamantan-1-yl)methanaminium chloride 1,4-dioxane hydrate structure.
Mentions: The computed crystal energy landscape (Fig. 3 ▸) of 1-adamantane­methyl­amine hydro­chloride was used to assess the possibility of solvent inclusion for this salt by estimating the percentage solvent-accessible volume in the predicted most stable packings. The most stable structure on the crystal energy landscape of the anhydrate displays a total potential solvent-accessible volume of 45.6 Å3, which corresponds to 3.71% of the unit-cell volume. Assuming that each water mol­ecule occupies an approximate total volume of 40 Å3, this would suggest that the global minimum structure could be crystallized by dehydration of a monohydrate of the salt. The global lattice energy minimum structure is approximately 6 kJ mol−1 more stable than the nearest competing second-ranked structure. The observation of a clearly preferred global lattice energy minimum structure with solvent-accessible voids is not conclusive in suggesting that this hydro­chloride salt cannot be crystallized as an anhydrate, but it does suggest that this system will have difficulties crystallizing as an anhydrate since there is an energetic preference for a packing of the ions that is susceptible to solvent inclusion. Although the second-ranked most stable predicted structure does not have any solvent-accessible voids, this structure is energetically competitive with the third-ranked structure which displays an unusually large percentage solvent-accessible volume of 17.42% of the unit cell. The majority of the predicted structures within 10 kJ mol−1 of the global minimum structure that have solvent-accessible voids have crystal voids that are located within 4.5 Å of the charged N+/Cl− ions, which is consistent with the observation that both the water and 1,4-dioxane solvent mol­ecules in the experimental structure engage in hydrogen-bonding inter­actions with the N+—H donor and Cl− acceptor groups of the salt.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Repeated attempts to crystallize 1-adamantane­methyl­amine hydro­chloride as an anhydrate failed but the salt was successfully crystallized as a solvate (2C11H20N+·2Cl−·0.5C4H8O2·H2O), with water and 1,4-dioxane playing a structural role in the crystal and engaging in hydrogen-bonding inter­actions with the cation and anion. Computational crystal-structure prediction was used to rationalize the solvent-inclusion behaviour of this salt by computing the solvent-accessible voids in the predicted low-energy structures for the anhydrate: the global lattice-energy minimum structure, which has the same packing of the ions as the solvate, has solvent-accessible voids that account for 3.71% of the total unit-cell volume and is 6 kJ mol−1 more stable than the next most stable predicted structure.

No MeSH data available.