Comparison of the crystal structures of methyl 4-bromo-2-(methoxymethoxy)benzoate and 4-bromo-3-(methoxymethoxy)benzoic acid

Abstract

The title compounds, C10H11BrO4, (I), and C9H9BrO4, (II), are derivatives of bromo–hydroxy–benzoic acids. Compound (II) crystallizes with two independent molecules (AandB) in the asymmetric unit. In both (I) and (II), the O—CH2—O—CH3side chain is not in its fully extended conformation; the O—C—O—C torsion angle is 67.3 (3) ° in (I), and −65.8 (3) and −74.1 (3)° in moleculesAandB, respectively, in compound (II). In the crystal of (I), molecules are linked by C—H...O hydrogen bonds, formingC(5) chains along [010]. The chains are linked by short Br...O contacts [3.047 (2) Å], forming sheets parallel to thebcplane. The sheets are linkedviaC—H...π interactions, forming a three-dimensional architecture. In the crystal of (II), moleculesAandBare linked to formR22(8) dimersviatwo strong O—H...O hydrogen bonds. These dimers are linked into ...A–B...A–B...A–B... [C22(15)] chains along [011] by C—H...O hydrogen bonds. The chains are linked by slipped parallel π–π interactions [inter-centroid distances = 3.6787 (18) and 3.8431 (17) Å], leading to the formation of slabs parallel to thebcplane.