Methylaminated potassium fulleride, (CH3NH2)K3C60 : towards hyperexpanded fulleride lattices.

Abstract

Co-intercalation of methylamine molecules into the cubic K3C60 lattice affords the fulleride (CH3NH2)K3C60, which was characterized by Raman and MAS 13C and 1H NMR spectroscopy. The high-resolution synchrotron X-ray powder diffraction technique was employed to determine its crystal structure at ambient temperature. We find that CH3NH2 bonds to K+ ions residing in the pseudo-octahedral interstices, thereby providing an efficient and facile route to hyperexpanded close-packed strongly anisotropic fulleride lattices, while retaining the electronic contact between the C603- anions. Preliminary evidence for the occurrence of a transition to an antiferromagnetic state at low temperature is also presented, consistent with the proximity of the present system to the metal-insulator boundary of the electronic phase diagram of C603- fullerides.