Conformer-dependent self-assembled metallacycles with photo-reversible response. Issue 18 (9th April 2019)

• Record Type: Journal Article
• Authors: Li, Mengqi; Chen, Li-Jun; Zhang, Zhipeng; Luo, Qianfu; Yang, Hai-Bo; Tian, He; Zhu, Wei-Hong
• Is Part Of: Chemical science. Volume 10:Issue 18(2019)
• Page Start: 4896
• Page End: 4904
• Publication Date: 2019-04-09
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9sc00757a
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : The scaffold sizes and shapes of a series of photoswitchable metallacycles are precisely controlled by the conformer of photoresponsive units. Abstract : Discrete, well-defined metallacycles and metallacages with stimuli-responsive behaviors have been largely predominated by the organic donor/metal acceptor paradigm with spontaneous formation of coordination bonds. However, light-driven self-assembly systems usually show relatively low utilization yield of photons and low fatigue resistance. Given that almost no example illustrates the different self-assembly behaviors of antiparallel and parallel conformers in the traditional photochromic diarylethene (DAE) system, here we have for the first time constructed a unique series of photoactive conformer-dependent metallacycles, focusing on the characterization and comparison of self-assembly behavior in different ligand conformers with different di-platinum(ii ) acceptors. Their photoswitchable scaffold sizes and shapes are precisely controlled by photochromically separable parallel or anti-parallel conformers via coordination-driven self-assembly. The ap-conformer and closed form provide larger bending angles upon coordination with di-Pt(ii ) acceptors into hexagon [6 + 6] or [3 + 3] while the p-conformer only can form smaller polygon cycles. Notably, in contrast with the non-photoactive parallel conformer, the reversible interconversion of anti-parallel ring-open and ring-closed conformer metallacycles can be achieved by alternate irradiation with UV and visible light, respectively, along with a relatively high conversion ratio and good fatigue resistance. This work provides a potential way to construct smart materials for use in sensing, catalysis and drug delivery systems.