6-Amino-5-(1-amino-2,2-dicyanovinyl)-3,3a,4,5-tetrahydro-2H-indene-4-spiro-1′-cyclopentane-3a,7-dicarbonitrilethiophene-2-carbaldehyde(1/0.5)

In each of the two independent indene-4-spiropentane molecules in the asymmetric unit of the title 2:1 adduct, C19H18N6 center dot 0.5C(5)H(4)OS, the cyclohexene ring adopts a half-chair conformation and the cyclopentene and cyclopentane rings adopt envelope conformations. The mean plane through the cyclohexene/cyclopentene fused system is aligned at a dihedral angle of 77.9 (1)degrees with respect to the mean plane through the cyclopentane ring in one molecule and 87.0 (1)degrees in the other. In the crystal, adjacent indene-4-spiropentane molecules are linked by N-H center dot center dot center dot N hydrogen bonds into a three-dimensional network. The spaces within the network are occupied by the thiophene-2-carbaldehyde molecules. The thiophene-2-carbaldehyde unit is disordered over two positions of equal occupancy. The crystal studied was found to be a non-morohedral twin with two minor twin components of 18.4 and 9.7%.