Oligothiophene‐Ring‐Strapped Perylene Bisimides: Functionalizable Coaxial Donor–Acceptor Macrocycles

Abstract

Aesthetic designs from nature enable new knowledge to be gained and, at the same time, inspire scientific models. In this context, multicomponent macrocycles embody the advantage of precisely positioning the structural units to achieve efficient communication between them. However, the construction of a functionalizable macrocycle for ultrafast charge separation and stabilization has not been attempted. Herein, we report the synthesis, crystal structure, and transient absorption of a new functionalizable macrocycle consisting of an oligothiophene-ring-strapped perylene bisimide. Transient absorption results point to a sequential improvement in charge separation and stabilization from the macrocycle to the corresponding linear dimer and 2D polymer due to the unique design. Our macrocycle design with a supportive spatial arrangement of the donor and acceptor units will inspire the development of more complex synthetic systems with exciting electron-transfer and charge-separation features.

A donor strapped perylene bisimide macrocycle and its lemniscate dimer with extended charge separation

“…1) as well and is due to the bay functionalization of PBI. 33 The dimer SP2D also retained almost the same red shift (∼15 nm) in absorption maximum compared to rPBI. The emission of SP2 and SP2D is completely quenched in CH 2 Cl 2 , and the intensity varies with solvent polarity (Fig.…”

“…1a, b, and Table S1 †). Normalized absorption spectra showed an ∼19 nm red shift in the absorption maximum from rPBI 33 to SP2 (Fig. 1a and S3 †).…”

“…N,N′-Dicyclohexyl-1,7-bis(2,6-dibromo-4-methylphenoxy)peril-ene-3,4:9,10-bisdicarboximide (1) was synthesized by adopting a previously reported procedure (72%). 33 The reaction of 1 with T2 (Scheme S1 †) without an alkyl chain on the thiophene-delivered molecule 2a in 88% yield (Scheme 1). Cleavage of the triisopropylsilyl group of 2a using tetrabutylammonium fluoride delivered the free acetylene molecule 3a, which is less stable under ambient conditions.…”

“…The observed reduction potentials are slightly shifted to the negative potential compared to rPBI. 33 In order to understand the difference in the reactivity of 3a and 3b, crystallization of 2a and 2b was attempted from the solvent mixtures CH 2 Cl 2 : MeOH (v/v; 50 : 50) and CH 2 Cl 2 : n-hexane (v/v; 50 : 50), respectively. The single crystal structure of 2a (CCDC 2247679 †) and 2b (CCDC 2247688 †) showed a marked difference in the orientation of the thiophene arm containing TIPS acetylene moieties.…”

“…17,18 Recently, our group also reported another oligothiophene strapped PBI, functionalized at the bay position via an oxidative coupling reaction, along with the corresponding linear dimer and a 2D polymer (Chart 1). 33 We aimed to develop macrocyclic donor-acceptor systems with extended charge separation (CS) and stabilization. In this work, we demonstrate another straightforward approach with acetylene chemistry, 34 which allows easily achievable covalently bonded, rigid macrocyclic scaffolds.…”