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Synthesis and Properties of a Decacyclene Monoimide and a Naphthalimide Derivative as Three‐Dimensional Acceptor–Donor–Acceptor Systems
Author(s) -
Yamamoto Yuma,
Yoshida Miu,
Morii Takuya,
Nishida Junichi,
Kitamura Chitoshi,
Kawase Takeshi
Publication year - 2018
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201701668
Subject(s) - adduct , delocalized electron , chemistry , derivative (finance) , acenaphthylene , acceptor , quantum yield , fluorescence , photochemistry , organic chemistry , phenanthrene , physics , quantum mechanics , financial economics , economics , condensed matter physics
A method involving the Diels–Alder (DA) cycloaddition of diacenaphtheno[1,2‐ b ;1′,2′‐ d ]thiophenes (DATs) with N ‐alkylacenaphthylene‐5,6‐dicarboximides (AIs) was developed to synthesize decacyclene monoimides (DCMIs). The reactions generate the corresponding 1:2 adducts (BAIAs) as major products together with 1:1 adducts (the DCMIs). The molecular structure of BAIAb ( N ‐octyl derivative) was unambiguously assigned as the bis‐adduct having an endo , endo spatial disposition of the two acenaphthylene‐5,6‐dicarboximide moieties by using X‐ray crystallographic analysis. Relative to the absorption spectrum of decacyclene triimide (DCTIa, N ‐2‐ethylhexyl derivative), that of the analogous N ‐2‐ethylhexyl‐substituted monoadduct, DCMIa, is bathochromically shifted despite the fact that it possesses a less delocalized π‐electron system. DCMIa does not fluoresce in various organic solvents, whereas DCTIa emits yellow fluorescence in CH 2 Cl 2 with a low quantum yield ( Φ SN ). Moreover, DCMIa in CDCl 3 displays concentration‐dependent 1 H NMR spectroscopy behavior, which suggests that it self‐aggregates with an association constant ( K a ) of (193±50) m −1 at 20 °C. Despite the presence of four bulky tert ‐butyl groups in DCMIa, its K a value for aggregate formation is comparable to that of DCTIa [(495±42) m −1 ], which does not contain tert ‐butyl substituents. Spectroscopic studies with the bis‐adduct BAIAa ( N ‐2‐ethylhexyl derivative) show that it displays remarkable solvatofluorochromism corresponding to an emission maximum shift (Δ λ EM ) of 100 nm. The results of density functional theory calculations on BAIAc ( N ‐methyl derivative) demonstrate that a considerable spatial separation exists between the HOMO and LUMO coefficient distributions, which indicates that the ground‐to‐excited state transition of the novel three‐dimensional acceptor–donor–acceptor BAIAa system should have intramolecular charge‐transfer character.