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Acylhydrazone Switches: E/Z Stability Reversed by Introduction of Hydrogen Bonds
Author(s) -
Lu Chaocao,
Htan Bu,
Ma Chunmiao,
Liao RongZhen,
Gan Quan
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201801466
Subject(s) - chemistry , isomerization , intramolecular force , hydrogen bond , solvation , solvent , molecular switch , low barrier hydrogen bond , photochemistry , solvent effects , hydrogen , computational chemistry , stereochemistry , molecule , catalysis , organic chemistry
We report a series of acylhydrazone‐based switches, of which double bond rotation can be stimulated by a pH response. The switches prefer Z rather than E configuration in the ground state because of the intramolecular hydrogen bonding, which was analyzed both thermodynamically and kinetically. Solvation studies show a linear relationship between the isomerization energy in Z/E states (Δ G E/Z o ) of the switches and the hydrogen bond basicity scales ( β and DN ) of the solvent. This solvent effect was also found to be relative to the skeleton of compound, the less shield of hydrogen bond domain the more sensitivity to the solvent environment. By introducing multiple intramolecular hydrogen bonds, the Z isomer completely predominates for compound 4 , offering an advantage over a full E/Z isomerization switching.