Intermolecular C-H···O and C-H···X interactions in substituted spiroacenaphthylene structures.

In the three spiroacenaphthylene structures 5''-[(E)-2,3-dichlorobenzylidene]-7'-(2,3-dichlorophenyl)-1''-methyldispiro[acenaphthylene-1,5'-pyrrolo[1,2-c][1,3]thiazole-6',3''-piperidine]-2,4''-dione, C(35)H(26)Cl(4)N(2)O(2)S, (I), 5''-[(E)-4-fluorobenzylidene]-7'-(4-fluorophenyl)-1''-methyldispiro[acenaphthylene-1,5'-pyrrolo[1,2-c][1,3]thiazole-6',3''-piperidine]-2,4''-dione, C(35)H(28)F(2)N(2)O(2)S, (II), and 5''-[(E)-4-bromobenzylidene]-7'-(4-bromophenyl)-1''-methyldispiro[acenaphthylene-1,5'-pyrrolo[1,2-c][1,3]thiazole-6',3''-piperidine]-2,4''-dione, C(35)H(28)Br(2)N(2)O(2)S, (III), the substituted aryl groups are 2,3-dichloro-, 4-fluoro- and 4-bromophenyl, respectively. The six-membered piperidine ring in all three structures adopts a half-chair conformation, the thiazolidine ring adopts a slightly twisted envelope and the pyrrolidine ring an envelope conformation; in each case, the C atom linking the rings is the flap atom. In all three structures, weak intramolecular C-H···O interactions are present. The crystal packing is stabilized through a number of intermolecular C-H···O and C-H···X interactions, where X = Cl in (I) and F or S in (II), and C-H···O interactions are observed predominantly in (III). In all three structures, molecules are linked through centrosymmetric ring motifs, further tailored through a relay of C-H···X [Cl in (I), Br in (II) and O in (III)] interactions.