2-Hydroxymethyl-1,3-dimethylimidazolium iodide

The crystal packing of the title compound, C6H11N2O+·I−, can be described as intercalated layers lying parallel to (010), with the iodide ions located between the cations. A weak intramolecular C—H⋯O hydrogen bond occurs within the cation. In the crystal, intermolecular O—H⋯I hydrogen bonds result in the formation of a three-dimensional network and reinforce the cohesion of the ionic structure.

The crystal packing of the title compound, C 6 H 11 N 2 O + ÁI À , can be described as intercalated layers lying parallel to (010), with the iodide ions located between the cations. A weak intramolecular C-HÁ Á ÁO hydrogen bond occurs within the cation. In the crystal, intermolecular O-HÁ Á ÁI hydrogen bonds result in the formation of a three-dimensional network and reinforce the cohesion of the ionic structure.
We are grateful to all personal of the PHYSYNOR laboratory, Université Mentouri-Constantine, Algeria, for their assistance. Thanks are due to the MESRS (Ministé re de l'Enseignement Supé rieur et de la Recherche Scientifique -Algé rie) for financial support.

Comment
The development of cleaner technologies is a major emphasis in green chemistry. Among the several aspects of green chemistry, the reduction/replacement of volatile organic solvents from the reaction medium is of utmost importance. The use of a large excess of conventional volatile solvents required to conduct a chemical reaction creates ecological and economic concerns. The search for a nonvolatile and recyclable alternative is thus holding a key role in this field of research. The use of fused organic salts, consisting of ions, is now emerging as a possible alternative. A proper choice of cations and anions is required to achieve ionic salts that are liquids at room temperature and are appropriately termed room temperature ionic liquids (RTILs) (Welton, 1999;Kubisa 2004;Corma & Garcia 2003;Sheldon, 2001;Wasserscheid & Kerm, 2000). The ionic liquids based on 1,3-dialkylimidazolium are becoming more important for several synthetic applications (Varma & Namboodiri 2001).
In this work, we report synthesis and the structure determination of an ionic compound obtained from the quaternization reaction of 1-methyl-2-hydroxymethylimidazole using methyl iodide (I).
The molecular geometry and the atom-numbering scheme of (I) are shown in Fig. 1. The asymetric unit of title molecule, C 6 H 11 N 2 O + , I -, contains a 2-hydroxymethyl-1,3-dimethylimidazolium cation and iodide anion.
The crystal packing can be described as intercalated layers parallel to the (010) plane, wich iodide ions are located between cations (Fig. 2). It is stabilized by weak intra and intermolecular hydrogen bonds [O-H···I and C-H···O] (Fig. 3).
These interaction bonds link the molecules within the layers and also link the layers together, forming a three dimensional network and reinforcing the cohesion of the ionic structure. Hydrogen-bonding parameters are listed in table 1.

Experimental
The title compound I was synthesized by treating 1eq of (1-methyl-1H-imidazol-2-yl)methanol by 3 eq of methyl iodide in refluxing THF during two days. The solid is filtered off and washed with boiling THF. Suitable crystals of I were obtained by crystallization from a CH 3 CN/THF solution.

Refinement
All non-H atoms were refined with anisotropic atomic displacement parameters. All H atoms were localized on Fourier  Fig. 1. (Farrugia, 1997) the structure of the title compound with the atomic labelling scheme.Displacement are drawn at the 50% probability level.  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 Rfactors(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.