X-ray structure of isomeric 3-chloro-4-(methylthio)- and 4-chloro-3-(methylthio)quinolines

Abstract

The crystal and molecular structures of two isomeric 3,4- and 4,3-chloro-(methylthio)quinolines have been determined. For 3-chloro-4-(methylthio)-quinoline (3-Cl−4-MeS−Q); triclinic, space group$\bar P1$,a=7.199(3),b=7.919(3),c=8.921(3) Å, α=89.74(3), β=74.29(3), γ=78.55(3)°. For 4-chloro-3-(methylthio)quinoline (4-Cl−3-MeS−Q): monoclinic, space group P2₁/n,a=12.860(4),b=5.424(2),c=13.434(4) Å, β=90.84(3)°. The values of the Cl...S distance as well as those for the Cl−C−C(S) and (Cl)C−C−S angles indicate the attractive interaction between ortho-situated heteroatoms in isomer 4-Cl−3-MeS−Q contrary to the effects observed in the case of 3-Cl−4-MeS−Q. The conclusions were confirmed by calculations of atomic charges withab initio method 4-31G basis set, which show positively charged sulfur atom in 4-Cl−3-MeS−Q and negatively charged sulfur in 3-Cl−4-MeS−Q.