Unexpected formation of 1,2- and 1,4-bismethoxyl Sc₃N@I_h-C₈₀ derivatives via regioselective anion addition: an unambiguous structural identification and mechanism study

Abstract

An attempt to achieve heterocyclic cycloadducts of Sc3N@Ih-C80 via the reaction with Ph2C=O, PhC≡CPh or PhC≡N in the presence of tetrabutylammonium hydroxide (TBAOH) stored in CH3OH led to the formation...

Decisive role of non-rare earth metals in high-regioselectivity addition of μ3-carbido clusterfullerene

“…1a, which includes only one orientation of the fullerene cage together with the major site of the Dy 2 TiC cluster for clarity (see ESI Table S1 † for detailed crystallographic data). Similar to other reported clusterfullerene-DPC cocrystals, [37][38][39] the asymmetric crystal unit cell consists of one pair of fully ordered DPC molecules and one Dy 2 TiC@I h -C 80 molecule. Meanwhile, two DPC molecules within 2DPC•{Dy 2 TiC@I h -C 80 } exhibit a V-shape geometry with a dihedral angle of 65.1°, and the nearest DPC-C 80 cage center distances are 7.08 Å/6.50 Å, which is evidently different from that of 2DPC•{Sc 3 N@I h -C 80 } with a dihedral angle of 1.4°and a DPC-C 80 cage center distance of 6.77/6.77 Å, 39 predicting the distinct electronic configuration of Dy 2 TiC@I h -C 80 , although they share the same I hsymmetry C 80 cage.…”

Advances in Regioselective Functionalization of Endohedral Metallofullerenes†

“…Sc 3 N@C 80 is the first discovered clusterfullerene [ 14 ] and a classical example of abundant but chemically inert NCF species. Lu and coworkers reported the alkoxylation [ 15 ] of Sc 3 N@C 80 to afford 1,4‐ and 1,2‐bismethoxyl adducts 5 and 6 (Scheme 1b), in which Sc 3 N@C 80 was treated with a methanol solution of tetrabutylammonium hydroxide (TBAOH) and iodine stepwise. Although two methoxy groups are added, this reaction is categorized in this monoaddition section, because the overall degree of unsaturation is reduced by one, while two sp 3 carbon atoms are formed on the cage, after the reaction, equivalent to a typical mono‐cycloaddition.…”

Effects of Solvents on Reaction Products: Synthesis of Endohedral Metallofullerene Oxazoline and Epoxide

“…It is worth mentioning here that the reaction between Sc 3 N@I h -C 80 and TBAOH (stored in CH 3 OH) conducted in o-DCB unexpectedly yielded two bismethoxyl derivatives of Sc 3 N@C 80 (Sc 3 N@C 80 (OCH 3 ) 2 ) due to the selective nucleophilic addition of CH 3 O − . 38 These results indicated the effects of solvents on the selective addition of nucleophiles and thus the final reaction products.…”

“…The distinct results from the reaction of Sc 3 N@I h -C 80 with TBAOH/CH 3 OH in o-DCB 38 and in PhCN demonstrate the important effects of solvents on the reactions. The results appear to be related to the polarity of the solvent.…”

“…According to the experimental results from the reactions of M 3 N@I h -C 80 with TBAOH/ CH 3 OH in three different solvents (o-DCB, 38 PhCN, and DMF) shown in Figure 6, there are two reaction paths at the initial stage, i.e., direct nucleophilic addition of CH 3 O − or OH − to the cage, depending on the solvent used in the reaction. TBAOH is an ammonium-based ionic liquid and a strong organic base.…”