Structures of S -(pyridin-2-yl) 4-nitro-benzo-thio-ate, S -(pyridin-2-yl) 4-methyl-benzo-thio-ate and S -(pyridin-2-yl) 4-meth-oxy-benzo-thio-ate: building blocks for low-symmetry multifunctional tetra-pyrroles.

The crystal structures of three S -(pyridin-2-yl) benzo-thio-esters with varying para -phenyl substituents are presented, namely, S -(pyridin-2-yl) 4-nitro-benzo-thio-ate ( 1 , C 12 H 8 N 2 O 3 S), S -(pyridin-2-yl) 4-methyl-benzo-thio-ate ( 2 , C 13 H 11 NO 2 S) and S -(pyridin-2-yl) 4-meth-oxy-benzo-thio-ate ( 3 , C 13 H 11 NO 2 S). This class of compounds are used in the mono-acyl-ation of pyrrolic species to yield multifunctional tetra-pyrroles. The structures presented herein are the first of their compound class. The dominant inter-actions present in this series are π-π stacking and C-H⋯O inter-actions, and as the para -phenyl motif changes from electron withdrawing (NO 2 , 1 ) to electron donating (OCH 3 , 3 ), changes are observed in the inter-actions present in the crystal packing, from predominant π-π stacking in 1 to exclusively C-H⋯O/N inter-actions (C ar-yl -H⋯O carbon-yl , C-H⋯O meth-oxy and C ar-yl -H⋯N pyridine ) in 3 .