Deuterated dimethyl sulfoxide as a good NMR solvent for the characterization of alkali metal cyclopentadienides, amides, alkoxides and phenoxides

Clamshell Opening in the Mixed‐Metal Supramolecular Aggregates Formed by Fourfold Reduced Corannulene for Maximizing Intercalated Metal Content

“…[15] The Li À Cp distances generally range from 3.8 to 4.1 in other cyclopentadienide organometallic compounds of lithium. Two remarkable mixed-metal products with a maximum amount of alkali-metal ions sandwiched between two nonplanar C 20 2À , have been isolated and fully characterized in this work. To allow this fit and thus to fully utilize all available corannulene binding sites, the two bowls should be moved farther apart.…”

“…[9,11,18] On the contrary, while the formation of four-fold reduced corannulene was clearly observed in the reaction mixture with Li and K metals, the assignment of the specific products in solution was problematic. [19] For example, lithium pentamethylcyclopentadienide (LiCp*) shows a peak at À12.5 ppm, [20] while shifts of 7 Li NMR signals up to À16 ppm [10b] are observed for the mixtures of corannulene and substituted fullerenes in the presence of an excess of Li metal. However, all attempts to crystallize the products from the above reaction mixtures in THF have failed.…”

Clamshell Opening in the Mixed‐Metal Supramolecular Aggregates Formed by Fourfold Reduced Corannulene for Maximizing Intercalated Metal Content

“…The previously unseen engagement of the hub-site of C 20 H 10 4À in lithium binding is accompanied by unprecedented shifts up to À24 ppm in 7 Li NMR spectra. The discussion of product formation mechanism, augmented by calculations, is provided.…”

“…As a result, the cooperative effect of alkali metals in self-assembly processes was revealed, leading to the discovery of a new class of organometallic supramolecules. Two remarkable mixed-metal products with a maximum amount of alkali-metal ions sandwiched between two nonplanar C 20 , have been isolated and fully characterized in this work. The mechanism of their formation along with other possible Li/K cluster compositions is discussed and augmented by DFT calculations.…”

“…It should be mentioned that Licontaining organometallic compounds generally show 7 Li NMR signals in the range from 0 to À20 ppm. [19] For example, lithium pentamethylcyclopentadienide (LiCp*) shows a peak at À12.5 ppm, [20] while shifts of 7 Li NMR signals up to À16 ppm [10b] are observed for the mixtures of corannulene and substituted fullerenes in the presence of an excess of Li metal. After numerous attempts and variations of experimental conditions, we have successfully crystallized the product from a diglyme/THF solution.…”