Rational Functionalization of a C₇₀ Buckybowl To Enable a C₇₀:Buckybowl Cocrystal for Organic Semiconductor Applications

Abstract

Fullerene fragments, referred to as buckybowls, are garnering interest due to their distinctive molecular shapes and optoelectronic properties. Here, we report the synthesis and characterization of a novel C70 subunit, diindeno­[4,3,2,1-fghi:4′,3′,2′,1′-opqr]­perylene, that is substituted with either triethylsilyl­(TES)-ethynyl or 2,4,6-triisopropylphenyl groups at the meta-positions. The resulting compounds (1 and 2) display a bowl-to-bowl inversion at room temperature. Notably, the substituent groups on the meta-positions alter both the geometric and the electronic properties as well as the crystal packing of the buckybowls. In contrast to the 2,4,6-triisopropylphenyl groups in 2, the TES-ethynyl groups in 1 lead to enhanced bond length alternation, resulting in weaker aromaticity of the six-membered rings of the buckybowl skeleton. 1 forms one-dimensional (1D) concave-in-convex stacking columns, and when 1 is blended with C70, the buckybowls encapsulate C70 and result in two-dimensional cocrystals. Organic field-effect transistor (OFET) measurements demonstrate that 1 displays a hole mobility of 0.31 cm2 V–1 s–1, and the 1-C70 cocrystal exhibits ambipolar transport characteristics with electron and hole mobilities approaching 0.40 and 0.07 cm2 V–1 s–1, respectively. This work demonstrates the potential of buckybowls for the development of organic semiconductors.

Macrocycle Co‐Crystals Showing Vapochromism to Haloalkanes

“…Charge‐transfer (CT) interactions are one of the most efficient driving forces in co‐crystal engineering [3a–e, 9] . In this system, macrocyclic container of perethylated pillar[5]arene (P5) was employed as donor owing to its π‐electron‐rich walls (Scheme 1).…”

Multifunctional Features of Organic Charge‐Transfer Complexes: Advances and Perspectives

“…Recently, diindeno[4,3,2,1‐ fghi :4 ′ ,3 ′ ,2 ′ ,1 ′ ‐ opqr ]perylene functionalized with triethylsilyl‐ethynyl (TES‐ethynyl) has been successfully synthesized as a p‐type buckybowl‐skeleton semiconductor with the mobility up to 0.31 cm 2 V −1 s −1 , which could co‐assemble with C 70 to fabricate 2D co‐crystals with strong concave‐convex interactions (Figure 9 a). [65] The C 70 is surrounded by neighboring buckybowls with multibump interactions, where centroid distances of the concave–convex interacting bowls and convex–convex interacting buckybowls are ≈14.32 Å and 15.98 Å, respectively, and C 70 ‐buckybowl interacts through short C−C contacts (Figure 9 b). The microplates (Figure 9 c), prepared by slow evaporation of toluene solution, illustrated ambipolar transport characteristics with an electron mobility of 0.40 cm 2 V −1 s −1 and a hole mobility of 0.07 cm 2 V −1 s −1 (Figure 9 d).…”

Multi‐Redox Active Carbons and Hydrocarbons: Control of their Redox Properties and Potential Applications

“…To date, various multi‐redox active C x H y molecules have been explored. These include, but are not limited to, nanographenes, [16–24] radicaloids (mostly based on diindenoarenes), [25–34] macrocycles, [35–39] fullerene fragments (including buckybowls), [40–45] nanographene‐buckybowl hybrids, [46] pentalene derivatives, [47] ethynylenes, [48] spiro‐compounds, [14] cumulenes, [49] other C x H y molecules with either the azulene, [50] barrelene, [51] fluoranthene, [52] fluorene, [53] diphenalene, [54] phenylene, [55] or Schwarzite framework, [56] and hydrofullerenes [57–61] . The redox properties of dissolved C x H y molecules are summarized in Table 1, where C x H y molecules that show at least six redox reactions (Scheme 1) are listed.…”