Solid state NMR and computational studies on cyclopentadienyl lithium

Lithiumcyclopentadienide, previously identified to be an endless polymer in the ligand-free solid state, was investigated by 13 C- and 6 Li-CP/MAS NMR spectra, and by B3LYP-GIAO theoretical calculations. By spectra simulation, the axially symmetric 13 C-shift tensor components were identified to be δ 11 = δ 22 = 151.5 ppm, δ 33 = 15.5 ppm. The 6 Li-tensor components are δ 11 = δ 22 = +1.0 ppm, δ 33 = −43.0 ppm. This extremely high field component is due to cumulative ring current effects. B3LYP-GIAO/TZVP calculations on the tensor principal components agree remarkably well with the measurements. A new and very simple method of preparing air-sensitive compounds for solid-state NMR analyses is described. Graphical abstract Shielding tensor main components from slow-speed solid state NMR spectra