CRYSTAL STRUCTURE OF RACEMIC ALPHA,ALPHA'-DIMETHYLGLUTARIC ACID

The crystal structure of racemic α,α′-dimethylglutaric acid has been solved using the conformational and close-packing principles previously applied to syndiotactic polypropylene chains. Refinement has been based on diffractometric intensities and has been accomplished by standard three-dimensional Fourier and least-squares methods to a final R value of 5.6%. Four molecules are contained in the monoclinic unit cell, which has space group symmetry C2/c. The structure consists of a van der Waals packing of endless chains of molecules connected by symmetrical pairs of hydrogen bonds between carboxyl groups. To within experimental error the hydrogen bonds, of length 2.634 Å, are linear, and all atoms of a given pair of hydrogen-bonded carboxyl groups are coplanar.