Strange Crystal Melts And Changes Color When Exposed to Light

A unique characteristic of a crystal has been discovered by a group of scientists from Osaka University in Japan. The solid organic substance changes into a liquid when it is subjected to the soothing glow of ultraviolet (UV) radiation.

Additionally, when this crystal melts, it experiences a fascinating series of variations in its luminescence that indicate modifications to the crystal's molecular structure.

It's not the first chemical to be found to go through the so-called photo-induced crystal-to-liquid transition (PCLT), however it is rare. But by utilizing light to examine the transition, researchers may be able to better comprehend it, which might lead to a variety of possible applications in photonics, electronics, and medicine administration.

According to scientist Mao Komura, this is the first organic crystal that we are aware of that displays a luminous evolution during crystal melting, demonstrating variations in intensity and hue, from green to yellow.

The substance is a heteroaromatic diketone, a kind of organic chemical that the scientists named "SO" because of the sulfur and oxygen found in its two rings.

The SO crystal compound emits a weak green glow when first exposed to UV light. But as the exposure goes on, it glows yellow and starts to dissolve. It is obvious that heating isn't what caused the transition based on careful observations of how sharp the border was between the two states.

The scientists discovered that diketone SO was actually changing from one chemical shape (skew) to another (planar) using theoretical calculations, a number of study approaches (including X-ray analysis and thermodynamic property analysis), as well as data from prior studies.

Other comparable crystal compounds that either didn't melt or did melt but didn't change color provided more information. That provides information to the researchers on the chemical alterations that take place as these crystals transform from solid to liquid.

Chemist Yosuke Tani from Osaka University explains, "We discovered that the changes in luminescence arise from sequential processes of crystal loosening and conformational changes prior to melting."

Working backwards, it demonstrates that these materials' unique molecular configuration is what causes them to melt and change phases when exposed to specific wavelengths of light.

And since it is non-invasive, ecologically safe, and very easy to accomplish, being able to manipulate materials with light might be highly valuable. A reversible adhesive that may be altered by exposure to light is one such use that the researchers offer.

The manner the diketone SO altered color was crucial to the advancements described in this work because it provided the researchers with crucial information about what was happening at the tiniest scales inside the crystal complex.

According to Tani, "These visual representations of the PCLT process steps allowed us to advance the current understanding of crystal melting at the molecular level."

The research has been published in Chemical Science.