Researchers designed a group of molecules that can bind to metal ions in the environment, according to a study conducted on August 15, 2018.
This study was conducted by the researchers at the University of Geneva (UNIGE), Switzerland. The newly designed family of molecules provides a light during binding, which is easily detectable. A 3D structure is formed by this sensor and the molecules are chiral. These molecules consist of a ring and two luminescent arms that emit a particular type of light in a process called Circular Polarized Luminescence (CPL), and selectively detect ions such as sodium.
Researchers compare these molecules to small locks: when they are ready to operate and detect the presence of metals, they emit a particular type of light (circularly polarized). When a metal ion is inserted, it acts on them like a key, the lock geometry changes and the light disappears.
These ‘locks’ are made up of two parts: a ring (a crown ether) that can encircle metal ions such as sodium and two twisted arms that extend from the rim and act like light bulbs, allowing researchers to see whether metal ions are present or not. When metal ions are not present, the two arms are close together and intense polarized luminescence is emitted. On insertion of a metal ion, the geometry of the molecule is changed, the arms move apart, and emission of light is stopped.
By removing the key, the luminescence of both arms is completely recovered. This on/off capability can be repeated over several on/off cycles, making these molecules effective and easy to read. The molecule thus behaves like a switch. Despite the functional complexity of the molecules, the new sensor can easily be assembled through only two synthetic steps, which could be established after three years of research.