Proton
transfer modulation in an organic diradical is apparently
the most conspicuously attractive phenomenon. In this work, we have
computationally designed the trans and cis forms of photochromic azobenzene- (AB-) bridged diradicals by considering
AB as coupler and two nitroxide (NO) as spin sources and a −OH
attaching at the ortho site as modulator. Our object is that through
intramolecular proton transfer to protonate the azo-unit (−NN−)
the magnetic coupling characteristics of the designed diradicals can
be modulated in their photocontrolled trans and cis forms. The calculated results indicate that PT can significantly
regulate the magnetic spin coupling constants, J =
−701.3 cm–1 ↔ −286.2 cm–1 for the trans form and −544.1
cm–1 ↔ −328.1 cm–1 for the cis form. In particular, we discover that
these designed magnetic molecules can undergo magnetic conversion
between antiferromagnetic and ferromagnetic coupling through PT, besides
there is considerable increase in the magnitude of their magnetic
coupling constants J, (e.g., −59.97 to 172.4
cm–1) for the trans-mode at the
m/m linking site. Moreover, we discover that the nitroxide radicals
at different linking positions have a significant impact and remarkably
alter the magnetic spin coupling characteristics of AB-based diradicals.
Besides, various radical groups are used as spin sources which corroborated
our assumptions and tended to the same conclusion. This work offers
a novel understanding of the spin interaction mechanism and a viable
approach for the rational design of new AB-based magnets which are
beneficial for further applications in the future.
The stable organic diradicals that show robust intramolecular magnetic coupling interactions are the pertinent building blocks for organic magnetic materials and design of the structure-controllable organic diradicals has extreme interest...
Magnetic conversion can be accomplished in a variety of ways, as organic molecules with switchable magnetic characteristics offer numerous technological applications. It is crucial to find the magnetism-switchable systems because,...
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