The solution and solid state structure of {[1-(dimethylamino)-8-naphthyl]lithium•THF}2

The reaction of N,N-dimethyl-1-naphthylamine with butyllithium agents is known to yield the peri lithiated product (3). The now reported structure of dimeric [1-(dimethylamino)-8-naphthyl]lithium with two molecules of THF (3 . THF)(2) shows a twist angle between the naphthyl-rings and the Li-C-ipso-Li plane of ca. 38 degrees. The magnitude of the (1)J(C-13,Li-7) coupling constant as well as the line splitting pattern of the lithiated carbon atom in the C-13 spectrum (THF-d(8)) demonstrate the existence of a dimeric species at -90 degreesC in solution. A previously published single crystal X-ray structure of dimeric [1-(dimethylamino)-8-naphthyl]lithium with two coordinating molecules of diethyl ether (3 . Et2O)(2) shows a smaller twist angle between the naphthyl-rings and the Li-C-ipso-Li plane of ca. 11 degrees. We assign this reduction of the twist angle to the weaker solvation properties of Et2O.