Structural studies of benzene derivatives. IV. Refinement of the crystal structure of p-methoxybenzoic acid

Abstract

The molecular geometry ofp-methoxybenzoic acid has been accurately determined in the solid state by a fullmatrix least-squares refinement of the atomic parameters given by Bryan [J. Chem. Soc. B (1967) The internal angles at the ipso atoms are % . = 120.2 (2) °, ~tcooH = 118.9 (2) °. Evidence is provided for C H~ .the existence of a measurable effect of the para substltuent on %ooH m para-substituted benzoic acids.

Molecular structure and charge density analysis of p-methoxybenzoic acid (anisic acid)

“…Cell constants and orientation matrix for data collection were obtained by a leastsquares procedure from the setting angles of 25 reflections in the angular range 17Њ Յ 2v Յ 37Њ centred by the diagonal slit method. The monoclinic cell parameters are: a = 16.961(2) Å , b = 10.958(1) Å , c = 3.9662(5) Å , b = 98.12(1)Њ, in good agreement with previous work [6]. This compound crystallizes in the space group P2 1 /a (spg.…”

“…The crystal structures of alkoxy-substituted benzoic acids have been the subject of several X-ray crystallographic studies [1][2][3][4][5][6], as these compounds show interesting chemical properties. In particular, certain members show liquid crystalline behaviour on melting [7,8].…”

“…In the case of anisic acid, the most recent crystallographic study was performed in 1978 by Colapietro and Domenicano [6]. The structure was refined by full matrix least-squares using 931 Bragg reflections with I Ͼ 4j measured on an X-ray diffractometer, leading to a final R-factor of 0.037.…”

Structure of sodiumpara-hydroxybenzoate, NaO2C–C6H4OH by powder diffraction: application of a phenomenological model of anisotropic peak width

“…A comparison of similar para-substituted benzene ring compounds in the literature [viz. phydroxybenzoic acid monohydrate (Colapietro, Domenicano & Marciante, 1979), p-nitrobenzoic acid (Colapietro & Domenicano, 1977), p-methoxybenzoic acid (Colapietro & Domenicano, 1978), p-¯uorobenzoic acid (Colapietro, Domenicano & Ceccarini, 1979), phydroxybenzoic acid and p-hydroxybenzoic acid± acetone complex (Heath et al, 1992), and potassium hydrogen di-p-hydroxybenzoate hydrate (Manojlovic, 1968)] shows that the deviations from planarity as well as the deviations from hexagonal symmetry for both groups are in the range of the standard uncertainties derived from the powder data. The rigid bodies were set up in a such a way that several intrameolecular bond distances remained as re®nable parameters, and only the bond lengths and angles of the C 6 ring were kept ®xed.…”

Structure of o-anisic acid

“…The crystal structure of pmethoxybenzoic acid has been described by Colapietro & Domenicano (1978). Experimental.…”