111975-69-0Relevant academic research and scientific papers
Y-Conjugated Dianions. A 13C Nuclear Magnetic Resonance Study
Rajca, Andrzej,Tolbert, Laren M.
, p. 871 - 876 (1988)
Tris(diphenylmethylene)methane dianion (12-), tetraphenylacetone dianion (22-), and diphenylacetate dianion (32-) were generated in dimethyl sulfoxide or tetrahydrofuran solutions by deprotonation of the appropriate carbon acid.Chemical shifts, carbon-carbon spin coupling constants, and other spectroscopic evidence indicated an sp2-hybridized central atom for all dianions, as well as D3 symmetry for the all-carbon dianion.The one-bond CC spin coupling constant for 12- (62 Hz) increased upon consecutive replacements of diphenylmethylene by the groups, i.e., to 69 Hz for 22- and 76.7 Hz for 32-,2K+ (86.0 Hz for the Li+ salt) reflecting charge localization at oxygen.An empirical model for the residual charge on phenyl-substituted resonance-stabilized carbanions that allows comparison of dissimilarly substituted carbanions was developed.
