Photochemical Addition of Ethers to C₆₀: Synthesis of the Simplest [60]Fullerene/Crown Ether Conjugates

Abstract

Easy crowning for [60]fullerene: The simplest and hitherto elusive C60/crown ether conjugates have been prepared through an effective free‐radical approach. This approach includes the activation of the otherwise unreactive α‐CH bond in a series of structurally diverse mono‐ or polyethers and sulfides. This facile method provides an expedient entry into a novel class of fullerene‐based materials.

Photochemical Reaction of o‐Phthalaldehyde with Fullerene C60: The Stimulus for the Phthalide Additions to C60

“…Another important finding from this experiment concerns the source of the fullerenyl hydrogen. The adduct 11-d 1 is partially deuterated (24 % D incorporation on the fullerene cage), which indicates, in consistence to the mechanism proposed in our previous studies, [9,[12][13][14] that the intermediate C 60 anion is mainly trapped by a proton originated from the residual moisture in the reaction mixture.…”

“…The presence of a normal isotope effect (k H /k D = 1.7 ± 0.1) shows that the rate-determining step of the reaction is the cleavage of the C-H or C-D bond as similarly found in our previous reactions on the TBADT-catalyzed reaction of C 60 with different substrates. [9,[11][12][13][14] This latter reaction expands further the synthetic utility of TBADT catalyst in fullerene functionalization chemistry by providing a new route to previously unexplored fullerene-based structures.…”

“…TBADT is a well-established photocatalyst for C-H bond activation in several classes of organic compounds. [11] For example, we have shown that TBADT can activate the benzylic C-H bond in toluenes [12] and also the α-C-H bond in ethers [13] to afford the corresponding C-centered radicals that can be effectively trapped by C 60 and give the respective mono-functionalized hydrofullerenes in moderate to good yields. We therefore envisaged that TBADT can activate the benzylic C-H bond in 2 to afford the anticipated radical addition adduct of C 60 , viz.…”

“…This result not only provides further evidence in support of the structure suggested for the product obtained from the reaction of C 60 with 1 (Table 1), but also constitutes a new synthetic example for the employment of TBADT catalysis in fullerene chemistry. [9,[12][13][14] The scope of this new TBADT-catalyzed reaction was further explored by studying the reaction of C 60 with three commercially available phthalides, namely 5bromophthalide (15), 5-cyanophthalide (16), and 6-nitrophthalide (17) ( Table 3, entries 2-4). Indeed, following the previous photocatalytic procedure, the corresponding radical intermediates were efficiently trapped by C 60 to yield selectively the monofunctionalized fullerene derivatives 18-20, respectively, in decent isolated yields (and almost quantitative recovery of unreacted C 60 ), thus validating the versatility and efficiency of this method.…”

Decatungstate‐Photocatalyzed Si−H/C−H Activation in Silyl Hydrides: Hydrosilylation of Electron‐Poor Alkenes

“…[18] Ac lear alternative is the hydrogen atom transfer from aS i ÀHb ond to ap hotogenerated tertbutoxyl radical( path b) [19] or to an excited photocatalyst (PC; path c), usually an aromatic ketone (e.g.,b enzophenone, xanthone). [20] Te trabutylammonium decatungstate (TBADT,( nBu 4 N) 4 -[W 10 O 32 ]) [21] has been adopted as ap hotocatalyst [22] for the regioselectivea ctivation of CÀHb onds in organic compounds and the ensuingf ormation of valuable CÀC, [23] CÀN, [24] and CÀF bonds. [25] TBADT in combination with silanes has been used recently for polymerization processes induced by the photogenerated silyl radicals.…”