Insecticides. Part 7. Crystal structures of 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethylene (DDE) and 1,1-dichloro-2,2-bis-(p-chlorophenyl)-ethane (DDD)

Abstract

The crystal structure of DDE has been determined from three-dimensional diffractometer data; Z= 8. in the monoclinic space group P2₁/c, with a= 921.9(1). b= 3 549.6(5), c= 943.8(1) pm, β= 114.70(1)°. The structure was refined by full-matrix least-squares to R 0.049. The inactivity of DDE could be due to its low conformational angles or to the effect of the double bond on the planarity of part of the molecule. The structure of the related compound, DDD: was also determined by direct methods. Z= 8. in the monoclinic cell, space group C2/c, a= 2 011.4(2), b= 769.2(1), c= 1 908.6(3) pm, β= 105.42(1)°. The structure was similarly refined to R 0.068. It is active and has similar conformational angles to those found in DDT.