The group is performing research on photochromic molecules for a broad range of applications.
Research Leader: Professor Joakim Andréasson
Dr Shiming Li
Dr Cassandra Fleming,
Dr Patricia Remón and Dr Marta Carrasco (together with Morten Grøtli GU)
Photochromic molecules, or photochromes, are molecules that can be isomerized between two, more or less, thermally stable forms using light. Upon isomerization, the absorption spectrum of the photochrome changes drastically. Usually, the thermally stable form absorbs almost exclusively in the UV region. Upon UV-exposure, the photochrome isomerizes to a visible-light absorbing species. Visible light triggers back-isomerization to the UV-absorbing form. The pronounced color change can be used for many applications, e.g., photochromic eye-wear.
In addition to the color change, there are also many other properties of the photochrome that change upon isomerization. For instance, the redox potentials, refractive index, charge distribution, and the structure are usually significantly different in the two forms. The figure below exemplifies both the structural and the spectral changes that follow upon isomerization of a photochromic molecule from the well-known spiropyran family.
|Structure and isomerization of a spiropyran derivative (left) and the corresponding absorption and emission changes (right). The absorption spectrum of the closed spiro form 1c is shown in blue. The corresponding spectrum of the open merocyanine form 1o is shown in red. Also shown is the emission spectrum of 1o (dotted red line). 1c displays no detectable emission.|
In our group, we are using derivatives from several different photochromic families to harness both the structural and the spectral changes for a broad range of applications, spanning photo-controlled biological processes (e.g. DNA-binding, membrane interactions, and kinase inhibition), chirality transfer, optical data storage, molecular logic, and signal processing. Current projects:
Research sponsored by: The Swedish Research Council (VR) and Olle Engkvist foundation.
Former group members:
Dr Tamara Pace
Dr Rubén Ferreira
Dr Joakim Kärnbratt