Highly switchable and shape-controlled photocatalysis within dye-based metal-organic frameworks

European Chemistry Congress

June 16-18, 2016 Rome, Italy

Tiexin Zhang

Dalian University of Technology, China

Posters & Accepted Abstracts: Chem Sci J

Abstract :

Photocatalysis could promote challenging chemical reactions via green energy, however, controlling the chemo-/ stereoselectivity of photocatalysis has long been hindered due to the dearth of effective binding strategy for substrates and the in situ generated radical species. Imposing additional interactions on substrates or radical species is beneficial to orienting the conformation of substrates or intermediates, favouring the chemo- or stereocontrol of photocatalysis especially when there are no covalent binding sites on the substrates. The other strategy is to â�?�?fixâ�? the reactive radical species via inner sphere modes of complexation with transition metal ions. By merging photoactive organic dyes and transition metals within metal-organic frameworks, the synergy of photocatalytic and transition metal catalytic cycles would be carried out, and the abundant non-covalent interactions sites within MOF channels are capable of imposing conformational orientation on substrates, resulting in perfect stereocontrol. When the MOF photocatalyst is comprised of Zn4O nodes and triarylaminebased ligand, aryltrifluoromethylation of unsaturated olefins could be conducted with enhanced diastereoselectivity. While the combination of Cu2(O2CR)4 paddle-wheel nodes and triarylamine-based ligand within MOFs switches to suppress the radical cyclization process, favouring the atom transfer radical addition (ATRA). The non-covalent interaction induced shape-control has been confirmed by X-ray single crystal diffraction experiments on the MOFs crystals encapsulating substrates. And the asymmetrically catalyzed ATRA is primarily examined after introducing chiral auxiliaries into the MOFs. zhangtiexin@dlut.edu.cn