May 6, 2024

Color-Changing Crystals: The Future of Molecular Switches Unveiled

Molecular switches are chemicals with molecular structures that can be moved between two or more steady configurations in action to changes in their environment. They are of fantastic interest in the advancement of molecular computer systems, molecular machines, and drug shipment systems. Substances with conformational isomers– identical molecular solutions but various molecular structures– can make really efficient molecular switches.
The methyl derivative of the brand-new substance has four various isomers, with various crystal structures each. They are particularly fascinating as molecular switches, as their sterically prevented double bond can offer isomers soaking up and emitting various wavelengths of light.”

Crystals of the recently synthesized compounds, anthraquinodimethane derivatives, which have different colors depending on their molecular structure. Credit: Yusuke Ishigaki
Freshly manufactured natural particles can be tuned to give off various colors depending on their molecular structures in crystal form.
Molecular switches are chemicals with molecular structures that can be shifted between two or more steady setups in response to modifications in their environment. They are of great interest in the advancement of molecular computers, molecular devices, and drug delivery systems. Compounds with conformational isomers– similar molecular solutions however various molecular structures– can make really efficient molecular switches.
The folded and twisted isomers take in different wavelengths of light. Credit: Kazuma Sugawara, et al. Materials Chemistry Frontiers. February 8, 2023
Scientists at Hokkaido University and Kyushu University have developed a strategy to manufacture prospective molecular switches from anthraquinodimethanes (AQDs), a group of overcrowded organic particles. The study, led by Associate Professor Yusuke Ishigaki at Hokkaido University and Associate Professor Toshikazu Ono at Kyushu University, was published in the journal Materials Chemistry Frontiers.

The methyl derivative of the brand-new compound has four different isomers, with various crystal structures each. Credit: Kazuma Sugawara, et al. Materials Chemistry Frontiers. February 8, 2023
” AQDs are a kind of overcrowded ethylene, particles with carbon-carbon double bonds surrounded by large chemical groups,” explains Ono. “They have 2 common isomers, the folded and twisted kinds. They are particularly interesting as molecular switches, as their sterically hindered double bond can provide isomers taking in and discharging various wavelengths of light.”
AQDs usually embrace the most steady folded or twisted kind, making it challenging to separate pure samples of any other isomer to study their residential or commercial properties. The scientists surmounted this obstacle by creating versatile AQD derivatives that can more easily and stably form different isomers.
When ground into amorphous solid and treated with proper solvents the light absorption and emission modifications. Credit: Kazuma Sugawara, et al.
The manufactured derivatives were not just able to stably form twisted and folded isomers, however likewise other isomeric forms, when recrystallized in different solvents. The scientists carried out detailed analysis of the derivatives to totally understand their properties.
Takanori Suzuki (left) Kazuma Sugawara (center) and Yusuke Ishigaki (ideal), authors from Hokkaido University. Credit: Yusuke Ishigaki
In a crystalline state, each of these isomers takes in and gives off distinct frequencies of light, which is because of the differences in the circulation of electrons in the isomer molecules. Remarkably, the light absorption and emission altered when the crystals were ground into amorphous solid, and following treatment with suitable solvents can produce original or other crystals with a variety of colors.
Yoshio Yano (left) and Toshikazu Ono (ideal), authors from Kyushu University. Credit: Toshikazu Ono
” This work is the very first report on the seclusion of multiple isomeric kinds of AQD,” Ishigaki concluded. “Their absorption and emission of various light frequencies, and more significantly, the capability to regulate the absorption and emission by external stimuli, make these substances exceptional prospects for the advancement of molecular switches.”
Recommendation: “Exceptionally flexible quinodimethanes with multiple conformations: polymorph-dependent colour tone and emission of crystals” by Kazuma Sugawara, Toshikazu Ono, Yoshio Yano, Takanori Suzuki and Yusuke Ishigaki, 8 February 2023, Materials Chemistry Frontiers.DOI: 10.1039/ D2QM01199A.
Financing: This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI and Grant-in-Aid for Research Fellows (JP20H02719, JP20K21184, JP21H01912, JP21H05468, JP20J20972); Toyota Riken Scholar; and a 2020 DIC Award in Synthetic Organic Chemistry, Japan.