C-13 magic-angle-spinning NMR study of the electronic properties of the AC(60) polymers (A=K, Rb, Cs)

Very high speed magic angle spinning (MAS) allows one to resolve the C-13 NMR spectra of the polymer phases AC(60). Spin lattice relaxation (T-1) data and T dependences of the spin shifts (for RbC60) allow us to resolve the signal of the bonding sties, which has all the features expected for sp(3) bonding. From spectral intensity analysis it is concluded that the distribution of spin densities is influenced by the ordering of the chains in the crystal. It differs markedly in KC60 from that found in the Rb and Cs polymers. The incidence of the electronic structure on the dimensionality of the magnetic properties of these systems is discussed.