A Facile Supramolecular Approach towards Strategic Fluorescence Switching and Recognition‐Controlled Photoreduction. Issue 2 (23rd November 2017)

• Record Type: Journal Article
• Authors: Roy, Bappaditya; Noguchi, Takao; Yoshihara, Daisuke; Sakamoto, Junji; Shinkai, Seiji
• Is Part Of: ChemPhotoChem. Volume 2:Issue 2(2018)
• Page Start: 67
• Page End: 71
• Publication Date: 2017-11-23
• Subjects: aggregation -- naphthalenediimide -- photoreduction -- responsive systems -- self-assembly; Photochemistry -- Periodicals; Periodicals; Electronic journals; 541.35
• DOI: 10.1002/cptc.201700188
• Languages: English
• ISSNs: 2367-0932

Abstract

Abstract: A supramolecular system design strategy to control photoreduction is reported. 1, 4, 5, 8‐naphthalenediimide (NDI) was used as the core unit to synthesize two different sets of ionic aromatic amphiphiles (AA), one incorporating the NDI with an aliphatic chain (denoted NDI) and the other with a phenoxy‐based chain (denoted NDI‐Phe). These systems form self‐assembled structures which are different to those in their monomeric states and which can selectively be photoreduced to generate the radical anion (NDI‐Phe .− ) and dianion (NDI 2− ) in the presence of dicarboxylic acids as the counter anion (CA). Interestingly, fluorescence (FL) switching was detected in the different redox states. The reduction mechanisms and the kinetics were found to be different for these two sets of AAs and the reduction kinetics were further controlled by the structurally different CAs. This unexpected observation reveals molecular recognition in the controlled‐assembly systems. The changes in spectroscopic output upon an electronic input have been described as a simple "off/on" FL switch. The appealing "bottom‐up" approach toward molecular device fabrication is possible only in molecular assembly systems such as these. Abstract : Take control : A supramolecular design strategy to control fluorescence switching and photoreduction is presented. Long‐chain naphthalenediimide‐based aromatic amphiphiles (as monomers or C2 H2 ‐bridged dimers) were combined with dicarboxylic acids (such as tartaric acid) as the counter anion. The reduction kinetics were influenced significantly by the nature of the counter anion.