Methyl 5-iodo-2-methoxybenzoate

In the title compound, C9H9IO3, the molecules are close to planar [maximum deviation from benzene ring plane = 0.229 (5) Å for the methyl carboxylate C atom] with the methyl groups oriented away from each other. In the crystal, molecules form stacked layers parallel to the ab plane, where every layer has either the iodine or methoxy/methyl carboxylate substituents pointing towards each other in an alternating fashion.

In the title compound, C 9 H 9 IO 3 , the molecules are close to planar [maximum deviation from benzene ring plane = 0.229 (5) Å for the methyl carboxylate C atom] with the methyl groups oriented away from each other. In the crystal, molecules form stacked layers parallel to the ab plane, where every layer has either the iodine or methoxy/methyl carboxylate substituents pointing towards each other in an alternating fashion.
We acknowledge the support from the Norwegian Research Council (project 190980), inGAP and the Department of Chemistry, UiO.
Supporting information for this paper is available from the IUCr electronic archives (Reference: LR2123).

Synthesis and crystallization
The title compound was synthesized by the method used by Wang et al. (2009), only differing slightly in the reaction time which was increased from 30 to 60 minutes. The 1 H NMR spectrum of the title compound is in good agreement with what was reported by Wang et al. (2009). The title compound was dissolved in CDCl 3 for NMR-analysis, and slow evaporation of the solvent yielded single crystals suitable for X-ray diffraction.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1. The structure was refined by fullmatrix least squares using SHELXL97 (Sheldrick, 2008) as implemented in the WinGX suite (Farrugia, 2012). H-atoms were positioned geometrically at distances of 0.93 (CH) and 0.96 Å (CH 3 ) and refined using a riding model with U iso (H)=1.2 U eq (CH) and U iso (H)=1.5 U eq (CH 3 ).

Results and discussion
The title compound is an intermediate in the synthesis of 4,4′-dimethoxy-3,3′-biphenyldicarboxylic acid, a novel organic linker for use in MOFs (Metal-Organic Frameworks). The title compound is a known intermediate from the literature (Wang et al., 2009), but the crystal structure has not been reported so far.
The structure of the title compound, C 9 H 9 IO 3 , has a monoclinic P2 1 /c symmetry. The asymmetric unit equals one molecule of the compound, with the full content of the unit cell generated by symmetry operations. The molecule has a planar motif where the methyl groups are oriented away from each other to accommodate the sterical demands of these groups. To further increase the distance between the methyl groups, an alternative configuration of the molecule could theoretically be achieved by rotating the methyl carboxylate group 180° around the C1-C7 bond. This however appears not to be an energetically favourable configuration in the solid state. The asymmetric units are packed to form layers parallel to the C plane, which results in a layered structure where every other layer has either an iodine or a methoxy/methyl carboxylate interface.    Packing diagram of the title compound viewed along the b axis. Hydrogen atoms are omitted for clarity. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.