Crystal packing in some flexible carboxylic acids and esters attached to a naphthalene ring

Abstract

A structural study of four dicarboxylic acids and four esters attached to a naphthalene ring is presented. (4-Carboxymethoxy-naphthalen-2-yloxy)-acetic acid (1) has a chain structure in the lattice while (6-carboxymethoxy-naphthalen-1-yloxy)-acetic acid (2) and (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid (3) adopt a sheet-like structure through weak intermolecular interactions, C–H⋯O and C–H⋯π hydrogen bonds. (3-Carboxymethylsulfanyl-1,4-dihydroxy-naphthalen-2-ylsulfanyl)-acetic acid has two symmetrically non-equivalent molecules per unit cell. The asymmetry is caused by weak C–H⋯S interactions. The packing pattern of the methyl esters differs significantly from the parent carboxylic acids and the packing patterns in each case were found to be determined by the C–H⋯O and C–H⋯π interactions.