The solution and solid state structure of {[1-(dimethylamino)-8-naphthyl]lithium&middotTHF}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&middotTHF)2 shows a twist angle between the naphthyl-rings and the Li-Cipso-Li plane of ca. 38°. The magnitude of the 1J(13C, 7Li) coupling constant as well as the line splitting pattern of the lithiated carbon atom in the 13C spectrum (THF-d8) demonstrate the existence of a dimeric species at -90 °C 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&middotEt2O)2 shows a smaller twist angle between the naphthyl-rings and the Li-Cipso-Li plane of ca. 11°. We assign this reduction of the twist angle to the weaker solvation properties of Et2O.