Towards the systematic crystallisation of molecular ionic cocrystals: insights from computed crystal form landscapes

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Towards the systematic crystallisation of molecular ionic cocrystals : insights from computed crystal form landscapes. / Mohamed, Sharmarke; Alwan, Ahmad A.; Friščić, Tomislav; Morris, Andrew J.; Arhangelskis, Mihails.

In: Faraday Discussions, 26.03.2018.

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@article{90d6a849145b4f978be24cb77707b7b5,
title = "Towards the systematic crystallisation of molecular ionic cocrystals: insights from computed crystal form landscapes",
abstract = "The underlying molecular and crystal properties affecting the crystallisation of ionic cocrystals (ICCs) with the general formula A−B+N (A− = anion, B+ = cation and N = neutral acid molecule; 1 : 1 : 1 stoichiometry) are reported for a limited set of known crystal structures determined following the cocrystallisation of either 4-aminopyridine (which forms salts) or 4-dimethylaminopyridine (which forms salts and ICCs) with the same set of monoprotic acids with a single hydroxy or halogen substitution at the ortho or para position. Periodic density functional theory calculations (PBE + D2) on the energetic driving force for ICC crystallisation for a set of known crystal structures with well characterised acid, salt and ICC structures show that all but 1 of the 7 experimental ICC structures surveyed were more stable than the sum of their component salt and acid structures with 4 displaying relative stabilities (ΔEICC) ranging from 2.47–8.02 kJ mol−1. The majority of molecular ICCs that are more stable with respect to their component salt and acid structures display the formation of discrete intermolecular O–Hacid⋯Oanion hydrogen bonds with the D11(2) graph set between the carboxylic acid OH donor and the carboxylate oxygen acceptor of the anion. Computed crystal form landscapes for model 1 : 1 salts derived from acid–base pairs (involving 4-dimethylaminopyridine) known to form molecular ICCs show that on average the most stable predicted polymorphs of the 1 : 1 salts have efficient packing of the ions with packing coefficients in the range 65–80% and this is comparable to the packing coefficients of the most stable predicted polymorphs of 1 : 1 salts (involving 4-aminopyridine) that have no ICCs reported. This suggests that the cocrystallisation of equimolar amounts of the 1 : 1 salt and the acid to form a 1 : 1 : 1 molecular ICC is a complicated phenomenon that cannot be explained on the basis of inefficiencies in the crystal packing of the salt ions.",
author = "Sharmarke Mohamed and Alwan, {Ahmad A.} and Tomislav Fri{\v s}{\v c}i{\'c} and Morris, {Andrew J.} and Mihails Arhangelskis",
year = "2018",
month = mar,
day = "26",
doi = "10.1039/C8FD00036K",
language = "English",
journal = "Faraday Discussions",
issn = "1359-6640",
publisher = "Royal Society of Chemistry",

}

RIS

TY - JOUR

T1 - Towards the systematic crystallisation of molecular ionic cocrystals

T2 - insights from computed crystal form landscapes

AU - Mohamed, Sharmarke

AU - Alwan, Ahmad A.

AU - Friščić, Tomislav

AU - Morris, Andrew J.

AU - Arhangelskis, Mihails

PY - 2018/3/26

Y1 - 2018/3/26

N2 - The underlying molecular and crystal properties affecting the crystallisation of ionic cocrystals (ICCs) with the general formula A−B+N (A− = anion, B+ = cation and N = neutral acid molecule; 1 : 1 : 1 stoichiometry) are reported for a limited set of known crystal structures determined following the cocrystallisation of either 4-aminopyridine (which forms salts) or 4-dimethylaminopyridine (which forms salts and ICCs) with the same set of monoprotic acids with a single hydroxy or halogen substitution at the ortho or para position. Periodic density functional theory calculations (PBE + D2) on the energetic driving force for ICC crystallisation for a set of known crystal structures with well characterised acid, salt and ICC structures show that all but 1 of the 7 experimental ICC structures surveyed were more stable than the sum of their component salt and acid structures with 4 displaying relative stabilities (ΔEICC) ranging from 2.47–8.02 kJ mol−1. The majority of molecular ICCs that are more stable with respect to their component salt and acid structures display the formation of discrete intermolecular O–Hacid⋯Oanion hydrogen bonds with the D11(2) graph set between the carboxylic acid OH donor and the carboxylate oxygen acceptor of the anion. Computed crystal form landscapes for model 1 : 1 salts derived from acid–base pairs (involving 4-dimethylaminopyridine) known to form molecular ICCs show that on average the most stable predicted polymorphs of the 1 : 1 salts have efficient packing of the ions with packing coefficients in the range 65–80% and this is comparable to the packing coefficients of the most stable predicted polymorphs of 1 : 1 salts (involving 4-aminopyridine) that have no ICCs reported. This suggests that the cocrystallisation of equimolar amounts of the 1 : 1 salt and the acid to form a 1 : 1 : 1 molecular ICC is a complicated phenomenon that cannot be explained on the basis of inefficiencies in the crystal packing of the salt ions.

AB - The underlying molecular and crystal properties affecting the crystallisation of ionic cocrystals (ICCs) with the general formula A−B+N (A− = anion, B+ = cation and N = neutral acid molecule; 1 : 1 : 1 stoichiometry) are reported for a limited set of known crystal structures determined following the cocrystallisation of either 4-aminopyridine (which forms salts) or 4-dimethylaminopyridine (which forms salts and ICCs) with the same set of monoprotic acids with a single hydroxy or halogen substitution at the ortho or para position. Periodic density functional theory calculations (PBE + D2) on the energetic driving force for ICC crystallisation for a set of known crystal structures with well characterised acid, salt and ICC structures show that all but 1 of the 7 experimental ICC structures surveyed were more stable than the sum of their component salt and acid structures with 4 displaying relative stabilities (ΔEICC) ranging from 2.47–8.02 kJ mol−1. The majority of molecular ICCs that are more stable with respect to their component salt and acid structures display the formation of discrete intermolecular O–Hacid⋯Oanion hydrogen bonds with the D11(2) graph set between the carboxylic acid OH donor and the carboxylate oxygen acceptor of the anion. Computed crystal form landscapes for model 1 : 1 salts derived from acid–base pairs (involving 4-dimethylaminopyridine) known to form molecular ICCs show that on average the most stable predicted polymorphs of the 1 : 1 salts have efficient packing of the ions with packing coefficients in the range 65–80% and this is comparable to the packing coefficients of the most stable predicted polymorphs of 1 : 1 salts (involving 4-aminopyridine) that have no ICCs reported. This suggests that the cocrystallisation of equimolar amounts of the 1 : 1 salt and the acid to form a 1 : 1 : 1 molecular ICC is a complicated phenomenon that cannot be explained on the basis of inefficiencies in the crystal packing of the salt ions.

U2 - 10.1039/C8FD00036K

DO - 10.1039/C8FD00036K

M3 - Article

JO - Faraday Discussions

JF - Faraday Discussions

SN - 1359-6640

ER -