Further Investigation of the Nature of the C‐Li Bond. Structures of a Phenylthiomethyllithium Complex and ofa Methylthiomethyllithium Complex

Phenylthiomethyllithium/ N , N , N ′, N ′‐tetramethylethylenediamine (TMEDA) (1:1) is shown by X‐ray analysis to be dimeric in the crystalline state. The structural unit contains a six‐membered ring in which each Li is bonded to the terminal C atom of one thioanisole and to the S atom of the other, as well as to the two N atoms of a TMEDA. Methylthiomethyllithium/TMEDA (1:1) is also dimeric, but the structural unit contains a four‐membered ring in which each Li is bonded to two C atoms and to the two TMEDA N atoms. An error has been detected in an earlier published electron‐density difference map for 2‐lithio‐2‐phenyl‐1, 3‐dithiane/TMEDA/THF (1:1:1). The conclusion drawn then that this complex exists as a tight ion‐pair in the crystal is now retracted.