In the title compound, C 8 H 5 ClN 2 O 2 (common name: 5-chloroisatin 3-oxime), the molecular structure deviates slightly from the ideal planarity, with a maximum deviation of 0.0478 (8) Å for the non-H atoms. In the crystal, molecules are linked by N-HÁ Á ÁO interactions, building centrosymmetric dimers with graph-set motif R 2 2 (8). Additionally, the molecules are connected by pairs of O-HÁ Á ÁO interactions into chains along [100] with a C(6) motif. The hydrogen-bonded dimers and chains build a two-dimensional network parallel to (100). The packing also features -stacking interactions between benzene rings [centroid-centroid distance = 3.748 (2) Å ]. Structure descriptionAs part of our study on the structural chemistry of isatin derivatives we report herein the crystal structure of 5-chloroisatin-3-oxime (for the asymmetric unit, see Fig. 1). The title compound is almost planar with an r.m.s. maximum deviation for the non-H atoms of 0.0478 (8) Å for O2. In the solid state, the molecules are connected into dimers via pairs of N1-H1Á Á ÁO1 interactions and a graph-set motif R 2 2 (8) is observed. In addition, the molecules are connected into chains with a C(6) graph-set motif by O2-H5Á Á ÁO1 hydrogen bonds (Fig. 2 and Table 1). The O-HÁ Á ÁO interactions connect the centrosymmetric dimers building a two-dimensional network, a tape structure, parallel to (100). As the outstanding feature, the ketone oxygen atom, O1, accepts two hydrogen bonds. As the difference between the two HÁ Á ÁO distances is less than 0.2 Å , the hydrogen bonds presumably have roughly equal strength and the arrangement may be described as symmetric. The packing also features -stacking interactions between benzene rings [centroid-centroid distance = 3.748 (2) A ].

Edited by C. Rizzoli, Universita degli Studi di Parma, Italy Keywords: crystal structure; Hirshfeld surface analysis; isatin derivative-VEGFR-2 in silico evaluation. CCDC reference: 1554287Supporting information: this article has supporting information at journals.iucr.org/eCrystal structure, Hirshfeld analysis and molecular docking with the vascular endothelial growth factor receptor-2 of (3Z)-5-fluoro-3-(hydroxyimino)-indolin-2-one

The reaction of hydroxyl­amine hydro­chloride with isatin in ethanol, catalysed with HCl and neutralized with Na2CO3, yielded the one-dimensional coordination polymer, catena-poly[[[aqua­sodium]-di-μ-aqua-[aqua­sodium]-bis­(μ-2-oxoindoline-2,3-dione 3-oximato)] tetra­kis­(oxoindoline-2,3-dione 3-oxime)], {[Na(C8H5N2O2)(H2O)2]·2C8H6N2O2}n. The NaI atom has a six-coordinate distorted-octa­hedral environment. Isatine-3-oximate O atoms and water mol­ecules bridge adjacent Na atoms, forming a one-dimensional polymeric structure parallel to [100]. Each isatine-3-oxime dimerizes through N—H⋯O interactions and in addition each oxime is linked to a coordination polymer. Thus, coordination polymers are linked by O—H⋯O and O—H⋯N interactions from isatine-3-oxime dimers, building a two-dimensional network parallel to [110].

Herein, we have notably described the electrochemical behavior of four isatin-thiosemicarbazone derivatives. In this regard, cyclic voltammograms of isatin-3-thiosemicarbazone (ITSC), isatin-3-(N 4 -benzylthiosemicarbazone) (ITSC-Ph), 1-(5-nitro-2-oxoindolin-3-ylidene)thiosemicarbazide (NO 2 -ITSC) and 1-(5-nitro-2-oxoindolin-3-ylidene)-4-phenylthiosemicarbazide (NO 2 -ITSC-Ph) have demonstrated an irreversible oxidation process. More specifically, the generation of isatin and thiourea moieties as the final oxidation products was proposed. The cyclic voltammograms also demonstrate irreversible reduction processes of ITSC and ITSC-Ph in three steps. The proposed final products are 3-aminoindolin-2-one and thiourea moieties. In the cyclic voltammograms of NO 2 -ITSC and NO 2 -ITSC-Ph, five reduction processes were observed: three of them due to reduction of the nitro group. It was proposed that the formation of 5-hydroxyamino-3-iminoindolin-2-one and the thiourea moieties would be the final products.

The crystal structure and the Hirshfeld surface analysis of a 5-fluoro­isatin 3-oxime and copper(II) complex are reported. In the crystal, the centrosymmetric complexes are linked by hydrogen bonding into a three-dimensional network. This work is the second report in the literature of a crystal structure with isatin 3-oxime derivatives acting as ligands (for metal complexes).