CO…HC interactions as packing motifs in crystals: Part 3. Impact of chloro-substituents on the structures of N-(chloro)-benzyl-3-spirocycloalkylopyrrolidine-2,5-diones

In continuation of the studies on weak H-bond formation in N-benzyl- and N-aminophenyl-succinimides, a series of six N-(chloro)-benzyl-3-spirocyclo-alkylpyrrolidine-2,5-diones was selected for crystallographic investigation. It was established that the presence of a strongly electron-withdrawing Cl-substituent does not destroy supramolecular synthons formed in other spiro-succinimides. Furthermore, the Cl-substituent participates in intermolecular Cl…HC interactions, non-classical weak H-bonds, which have not yet been fully described. Therefore, descriptive parameters of such interactions: D and the Θ, were estimated on the basis of the structures and the statistics from the CSD search. Distance D was established to be in the range of 3.2– 4.2 Å and the Θ angle in the range of 100–180°.