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Tuning solubility and stability of hydrochlorothiazide co-crystals

“…HCT-NCT (1:1) co-crystal. The HCT-NIC and HCT-NCT co-crystals are isomorphs (Smolka et al, 1999;Sarma et al, 2008). The HCT-NCT co-crystal (space group P2 1 2 1 2 1 , Z = 4) contains nicotinamide molecules forming onedimensional chains parallel to the a axis through amideÁ Á Ápyridine synthons involving N-HÁ Á ÁN hydrogen bonds (N4-H4BÁ Á ÁN5; Table 2; Fig.…”

Four- and five-component molecular solids: crystal engineering strategies based on structural inequivalence

“…In the first, the same chemical functionalities in A or B are located in the same crystal environment and are not susceptible to any further supramolecular differentiation. In the second type, however, the same functional groups in say B are found in two types of crystal environments which we shall refer to as B 1 and B 2 , or they are potentially capable of such differentiation (Smolka et al, 1999). These crystal environ- ments (or potential environments) may be sufficiently distinct so that a new entity C that is introduced will be able to discriminate between the sites and replace just one of B 1 or B 2 , to give a ternary.…”

A cocrystallisation-based strategy to construct isostructural solids

“…22 We have recently explored the structural similarity of chloro and methyl groups in the context of cocrystals based on infinite hydrogen-bonded networks, 23 while Thalladi and co-workers 17 demonstrated the use of chloro/methyl structural similarity to construct pairs of isostructural cocrystals with different thermal properties. Structural equivalence of aromatic CH and N groups in multi-component cocrystals was demonstrated by Boese and co-workers, 24 as well as Babu and Nangia. 25 In the context of halogen-bonded cocrystals, it has been recently demonstrated that Br and I substituents become structurally equivalent when participating in halogen bonding.…”

“…The isostructurality of (phen)Á(ipb) and (acr)Á(ipb) demonstrates the structural equivalence of aromatic CH and N moieties of acr and phen, respectively. Previous examples of structural equivalence involving CH and N groups include finite hydrogen-bonded assemblies of acr and phen with 2,2 0 -dihydroxybiphenyl, 24 and extended hydrogen-bonded frameworks of pyrazine tetracarboxylic acid, pyridinetetracarboxylic acid and pyromellitic acid dihydrates. 25 In contrast, pure acr and phen in the solid state adopt mutually different crystalline arrangements.…”