Simultaneous determination of the lithium-6 nuclear quadrupolar coupling constant and chemical shift anisotropy in monomeric tri(isopropyl)phenyllithium

Line shape analysis of the natural abundance 6Li cross polarization NMR powder spectrum of 2,4,6-tri(isopropyl)phenyllithium yields a 6Li quadrupolar coupling constant, χ, of (±)6.63 ± 0.10 kHz and a Li chemical shift anisotropy, Δδ, of +24 ± 4 ppm. The 6Li and 7Li spectra and the 13C CP/MAS spectrum indicate that solid 2,4,6-tri(isopropyl)phenyllithium exists as a monomer, in contrast to the reported dimeric structure of the solid etherate. Ab initio molecular orbital calculations (MP2/6-31G ∗ ∗) for phenyllithium yield a χ(6Li) value of 7.38 kHz.