Crystal structure of r-1,c-2-dibenzoyl-t-3,t-4-bis-(2-nitro-phen-yl)cyclo-butane.

The condensation reaction of aceto-phenone (1-phenyl-ethan-1-one) with 2-nitro-benzaldehyde in the molten state yielded the expected chalcone, (E)-3-(2-nitro-phen-yl)-1-phenyl-prop-2-en-1-one, and, unexpectedly, the title compound, C30H22N2O6, which results from the syn head-to-head [2 + 2] cyclo-addition of the chalcone. The mol-ecular structure of the dimer shows that the four benzene rings of the substituents are oriented in such a way that potential steric hindrance is minimized, whilst allowing some degree of inter-molecular π-π inter-actions for crystal stabilization. In the mol-ecule, one nitro group is disordered over two positions, with occupancies for each part of 0.876 (7) and 0.127 (7).