Abstract
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.
Original language | English (US) |
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Pages (from-to) | 871-876 |
Number of pages | 6 |
Journal | Journal of the American Chemical Society |
Volume | 110 |
Issue number | 3 |
DOIs | |
State | Published - Feb 1988 |
Externally published | Yes |
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry