Portalone Gustavo
Chemistry Department, "Sapienza" University of Rome, P.le A. Moro, 5, I-00185 Rome, Italy.
Acta Crystallogr Sect E Struct Rep Online. 2009 Jan 17;65(Pt 2):o327-8. doi: 10.1107/S1600536809001408.
The crystal structure of the title compound, C(9)H(10)O(4), was first reported by Swaminathan, Vimala & Lotter [Acta Cryst. (1976), B32, 1897-1900]. It has been re-examined, improving the precision of the derived geometric parameters. The asymmetric unit comprises a non-planar independent mol-ecule, as the meth-oxy substituents force the carb-oxy group to be twisted away from the plane of the aromatic ring by 56.12 (9)°. Due to the anti-planar conformation adopted by the OH group, the mol-ecular components do not form the conventional dimeric units, but are associated in the crystal in chains stabilized by linear O-H⋯O hydrogen bonds, involving the OH groups and the carbonyl O atoms, which form C(3) motifs.
标题化合物C(9)H(10)O(4)的晶体结构首次由斯瓦米纳坦、维马拉和洛特报道[《晶体学报》(1976年)，B32，1897 - 1900]。现已重新研究，提高了导出几何参数的精度。不对称单元包含一个非平面独立分子，因为甲氧基取代基迫使羧基从芳环平面扭转56.12 (9)°。由于OH基团采取反平面构象，分子组分不形成传统的二聚体单元，而是在晶体中通过线性O - H⋯O氢键形成链状缔合，涉及OH基团和羰基O原子，形成C(3) motif。
