Inorganic Chemistry, Vol.42, No.12, 3849-3855, 2003
Structural diversity of lithium sulfenamides: Li-7 NMR studies in solution and crystal structures of [Li-2(n(2)-(CH3)(3)C-NS-C6H4CH3-4)(2)(THF)(2)] and [Li-2(n(1)-4-CH3C6H4-NS-C6H4CH3-4)(2)(THF)(4)]
Two lithium sulfenamides were prepared by reaction of (CH3)(3)C-N(H)-S-C6H4CH3-4 (1) and 4-CH3C6H4-N(H)-S-C6H4CH3-4 (2) with an alkyllithium. The unsolvated sulfenamide Li[(CH3)(3)C-NS-C6H4CH3-4] (3) was soluble enough for variable-temperature (VT) Li-7 NMR to provide evidence of a dynamic exchange of oligomers in solution. The crystal structures of the solvated sulfenamides of [Li-2(eta(2)-(CH3)(3)C-NS-C6H4CH3-4)(2)(THF)(2)] (4) and of [Li-2(eta(1)-4-CH3C6H4-NS-C6H4CH3-4)(2)(THF)(4)] (6) consisted of dimers in which the anions display different hapticities. The VT Li-7 NMR spectra of 4 suggest that the two different structures exist in equilibrium in toluene-THF mixtures. These compounds are easily oxidized to the neutral thioaminyl radicals as identified by EPR spectroscopy.