X-ray crystallographic study of diversely substituted isatin derivatives

A series of isatin derivatives were synthesized and studied by XRD. For the first time the peculiarities of the molecule structure and crystal packing effects were analyzed. Indoline heterocycles are planar in all the investigated structures. The molecules bearing the sterically hindered substituents at nitrogen atom of indoline heterocycle have the maximum deviations of two oxygen atoms from the indoline plane. The substituent nature at nitrogen atom does not effect on the bond lengths of indoline moiety. The value of endocyclic bond angle at nitrogen not so strongly depends on the substituent and is almost equal to the one in unsubstituted isatin. In contrast to the unsubstituted isatin, where the system of classical hydrogen NH⋯O-bonds is realized, in crystals of investigated compounds there is no opportunity to reveal ones, and the crystal structure is stabilized by CH⋯O- and π–π-interactions.