Generation and Nuclear Magnetic Resonance Studies of 9-Heteroanthracenide Anions: 9-Selena-, 9-Phospha-, and 9-Arsaanthracenides

Article abstract of DOI:10.1021/jo00233a030

The thermally stable heteroanthracenide ions 9d-g were generated upon exposure of the respective conjugate acids 8d-g to KNH2 in liquid NH3 and were studied by 1H, 13C, and 31P NMR.It is shown that 9d possesses a paratropic molecular frame, while 9e and 9f exhibit no detectable paramagnetic ring current effect.Possible electronic and steric interactions that may give rise to the observed NMR characteristics of 9e-g are discussed, and it is concluded that the carbanionic charge in these anions is substantially delocalized over the central ring involving the heteroatomic unit.