In Avogadro [ ], we build isolated PyC-m-X and PyC-o-X ligands-PyC ligands in which an H atom at the meta and ortho position, respectively, is replaced by functional group X-and optimize their geometry using the Universal Force Field (UFF) [ ]. We then store the coordinates of the C-(C-X)-C and N-(C-X)-C fragments belonging to the optimized PyC-m-X and PyC-o-X ligands, respectively.