Synthesis of Fully Substituted Sumanenes at the Aromatic Periphery through Hexabromomethylation

Abstract

Hexakis(bromomethyl)sumanene, a hexasubstituted sumanene with bromomethyl groups at the peripheral aromatic carbons, was successfully synthesized in 97% yield with a one-step reaction. Single-crystal X-ray structural analysis showed a formation of a dimer structure.The nucleophilic substitution afforded the introduction of several substituents. These UV-vis absorption and emission spectra showed clear redshift compared with pristine sumanene, indicating the extension of the conjugation system of hexa-substituted sumanenes.

Pentagon-Fused Sumanenes on the Aromatic Peripheries en Route to the Bottom-Up Synthesis of Fullerenes

“…Probably the redshift of 2 compared to pristine sumanene is due to the expansion of the orbitals to nitrogen atom by through-bond interaction. 13 18 In the emission spectra (λ em = 360–700 nm), the same result was observed (Figure S4b). Additionally, triamines 2 exhibited a characteristic emission around 500–600 nm.…”

“…12 Recently, we have reported the facile synthesis of bromomethylsumanene ( 1 ) in one step from sumanene, and on its derivatization affording varieties of hexa-substituted sumanene derivatives. 13 Inspired by the results, we noticed that the introduction of C1 or N1 units to 1 via substitution reaction enables the construction of cyclopentane (C 30 framework) or pyrrolidine rings (C 27 N 3 framework) on the periphery of the sumanene skeleton, which corresponds to the half structure of C 60 and C 54 N 6 , respectively, and satisfies the IPR (Figure 1 , bottom). In addition, we considered that the existence of benzylic carbons, characteristic of sumanene, allows further functionalization to adjust the required functional groups for convergent synthesis-oriented dimerization of the two fragments via six-membered ring formation.…”

“…Since our previous studies have shown that 1 is unstable under strongly basic conditions, 13 our study commenced with the discovery of reaction conditions under a less basic or neutral environment. When 1 was treated with n -butylamine (300 mol%) and sodium hydrogen carbonate, decomposition of 1 occurred to afford a black insoluble precipitate (Table 1 , entry 1).…”

Supramolecular Chemistry of Sumanene

“…There are many recent works dealing with the synthesis of structurally-enhanced sumanene derivatives, which despite not being used in supramolecular architectures to date, may be envisioned as their potential building blocks. Those include, but are not limited to, hexasubstituted sumanene derivatives [18][19][20][21][22] (including the ideas towards the bottom-up synthesis of fullerenes [23] ) or πexpanded sumanene derivatives (including sumanene-fused acenes, [4] C 70 /C 60 fragments, [24,25] heteroatom-doped sumanene-related polycycles [26] ), see structures in Figure 5. Defi-nitely, above-noted synthetic achievements will provide next generations of functional supramolecular materials in the coming years, also taking into account recently demonstrated applications of hexa-substituted sumanenes in this field.…”

Supramolecular Chemistry of Sumanene

“…There are many recent works dealing with the synthesis of structurally-enhanced sumanene derivatives, which despite not being used in supramolecular architectures to date, may be envisioned as their potential building blocks. Those include, but are not limited to, hexasubstituted sumanene derivatives [18][19][20][21][22] (including the ideas towards the bottom-up synthesis of fullerenes [23] ) or πexpanded sumanene derivatives (including sumanene-fused acenes, [4] C 70 /C 60 fragments, [24,25] heteroatom-doped sumanene-related polycycles [26] ), see structures in Figure 5. Definitely, above-noted synthetic achievements will provide next generations of functional supramolecular materials in the coming years, also taking into account recently demonstrated applications of hexa-substituted sumanenes in this field.…”