Effect of chlorine substitution on the structure and activity of 4-phenylthiosemicarbazide: crystal and molecular structure of 4-(4-chlorophenyl)thiosemicarbazide

Abstract

The crystal structure of 4-(4-chlorophenyl)thiosemicarbazide has been determined by direct methods. This p-chloro-substituted 4-phenylthiosemicarbazide, with greater antibacterial activity than its unsubstituted precursor, crystallises in the space group P2₁/c with a= 14.594(4), b= 10.495(5), c= 12.384(4)Å, β= 104.73(2)°, Z= 8, D_c= 1.469 g cm^–3, and µ(Mo-K_α)= 5.83 cm^–1. The structure has been refined using 1 967 reflections with I 3σ(I). The antibacterial activity of both the present compound and its precursor has been attributed to electron delocalisatoin in the thiosemicarbazide moiety enhancing both its donor and reductive capacities.