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Post‐Functionalization of Supramolecular Polymers on Surface and the Chiral Assembly‐Induced Enantioselective Reaction
Author(s) -
Li DengYuan,
Zhu YaCheng,
Li ShiWen,
Shu ChenHui,
Liu PeiNian
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202016395
Subject(s) - enantioselective synthesis , surface modification , porphyrin , supramolecular chemistry , chirality (physics) , steric effects , enantiomer , chemistry , coupling reaction , combinatorial chemistry , materials science , stereochemistry , photochemistry , catalysis , organic chemistry , molecule , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
Although post‐functionalization is extensively used to introduce diverse functional groups into supramolecular polymers (SPs) in solution, post‐functionalization of SPs on surfaces still remains unexplored. Here we achieved the on‐surface post‐functionalization of two SPs derived from 5,10,15‐tri‐(4‐pyridyl)‐20‐bromophenyl porphyrin (Br‐TPyP) via cross‐coupling reactions on Au(111). The ladder‐shaped, Cu‐coordinated SPs preformed from Br‐TPyP were functionalized through Heck reaction with 4‐vinyl‐1,1′‐biphenyl. In the absence of Cu, Br‐TPyP formed chiral SPs as two enantiomers via self‐assembly, which were functionalized via divergent cross‐coupling reaction with 4‐isocyano‐1,1′‐biphenyl (ICBP). Surprisingly, this reaction was discovered as an enantioselective on‐surface reaction induced by the chirality of SPs. Mechanistic analysis and DFT calculations indicated that after debromination of Br‐TPyP and the first addition of ICBP, only one attack direction of ICBP to the chiral SP intermediate is permissive in the second addition step due to the steric hindrance, which guaranteed the high enantioselectivity of the reaction.