Fast dark cis-trans isomerization of azopyridine derivatives in comparison to their azobenzene analogues: Experimental and computational study

Photochemical anti–syn isomerization around the –N–N bond in heterocyclic imines

“…[27][28][29] Recently, photochemically-induced isomerization of a quinazolinone derivative containing a large p-system (consisting of two C 6 rings linked by a reduced quinazolinone moiety and a N ring -N]CH-C aromatic bridge) has been described. 30 Unlike previous studies describing isomerization around a C-C linkage [27][28][29] or a N]N linkage (in the case of azobenzene and its derivatives), 31,32 isomerization proceeded around a N-N linkage in the N-N]CH array of this system. This nding prompted us to study similar molecular systems, and in this paper we present experimental data and in-depth theoretical analysis to identify the excited states that are likely to be involved in the photochemically-induced isomerization process.…”

Nanoscale Coordination Polymer of Dimanganese(II) as Infinite, Flexible Nanosheets with Photo‐Switchable Morphology

“…Solvent loss is also evident on the DSC curve at first heating at about 50 °C, which also indicates a glass transition at –82 °C. On the second heating, the DSC curve indicate only glass transitions, at –51, assigned to C x 2– moiety that is slightly higher than that in free H 2 C x ,[11c] and 33 °C attributed to the azopyridine segment . The occurrence of two glass transition indicates a biphasic morphology.…”

“…10.53 wt.‐%; found 10.55 wt.‐%). The main weight loss (26.96 wt.‐%) corresponding to compound decomposition occurs around 292 °C with T peak at 331 °C, when methyl groups but also azopyridine could be lost, although the sum of their shares in the structure (9.87 and 30.31 wt.‐% respectively) is higher than the lost mass. In the same time, a high amount of residue is recorded, 45.56 wt%, which probably consists mainly of silicon and manganese oxides.…”

Azopyridine: a smart photo- and chemo-responsive substituent for polymers and supramolecular assemblies

“…It ranges from several hours to a few minutes. 10 Work carried out earlier with azobenzene (Azo) established that the cis-to-trans dark relaxation time decreases to a few seconds by introducing in the azobenzene molecule a substi-tution pattern that produces a "push-pull" electronic distribution, such as a dimethylamino group at the C4 position and a nitro group at the C4′ position of Azo. 11,12 The cis-to-trans dark relaxation time reaches the desired microsecond time domain by replacing a phenyl ring of azobenzene with a pyridinium ring that is a more powerful electron-withdrawing group than -NO 2 .…”