Control of Crystal Growth
Our unique and extremely promising approach is based on the innovative application of magnetic fields to organic crystal growth. While the preparation of materials in the presence of electric field is an established method (used for example in the alignment of nonlinear optical materials) to date the influence of magnetic fields on the growth of materials has been largely focussed on those materials which develop strong interactions with the external magnetic field.
In a recent series of proof-of-principle experiments we were able to grow a hitherto unknown polymorph of the polyaromatic hydrocarbon coronene in a magnetic field. We discovered that strong magnetic fields couple to organic molecules and enable the orientation of pre-crystallisation clusters of different polymorphs in solution prior to crystal growth. Our characterisations have shown that the new crystal of β-coronene formed in the magnetic field is the lowest energy polymorph and exhibits a remarkably altered angle between the molecular planes.
As a result of the new supramolecular configuration the electronic, optical and mechanical properties have been significantly changed. This is the new experimental handle that will allow us to take the first concrete step towards our long term vision of applying this to pharmaceutical products. This is an ambitious step to take, but reliable production of the desired polymorphs of pharmaceutical compounds will transform the industry irrevocably and for the better.
Optical images of the new β-polymorph (orange crystals) and usual γ-polymorph (yellow crystals) of coronene.
The squares on the grid are 0.5 cm × 0.5 cm.