Crystal structure of a second polymorph of germacrone, C15H22O

Abstract

The crystal structure of a new polymorph of germacrone has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. This polymorph (Form II) crystallizes in space group C2/c (#15) with a = 26.0073(4), b = 9.84383(10), c = 10.53713(13) Å, β = 95.7547(11)°, V = 2684.04(3) Å3, and Z = 8. The crystal structure is dominated by van der Waals interactions, but four C–H⋯O hydrogen bonds are present. The structure exhibits many similarities to the previously reported Form I polymorph FIQLOG, but is clearly different. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF).