Molecular factories based on {M(2,2':6',2''-terpyridine)2}2+–zipped co-block polymer vesicles
We show how the chelating power of bis(2,2':6',2''-terpyridine)metal(II) complexes can be applied to 'zip' together co-block polymer vesicles to give pre-organized assemblies.1 Different approaches have been used to functionalize polymer vesicles which condense with appropriately functionalized 2,2':6',2''-terpyridine (tpy) domains; sequential reaction with metal ions e.g. Fe2+ leads to an organized assembly. All reactions are carried out under ambient conditions and in aqueous media. The principle of the procedure is shown in the scheme below:
Figure 1: Strategy for assembly of arrays of coupled polymer vesicles.
The characteristic MLCT absorption associated with the {Fe(tpy)2}2+ chromophore is a powerful probe with which to assess the degree of vesicle aggregation. This along with AFM and TEM studies will be discussed.
The ordered structure of the polymer vesicle assembly provides a platform for an array of artificial compartments for a molecular factory. Surface modification is particularly attractive.2 Future directions of the work will be discussed, e.g. encapsulation of components of the 'factory' within hollow vesicles and communciation between the compartments.
[1] Constable, E.C.; Meier, W.; Nardin, C.; Mundwiler, S. Chem. Commun. 1999, 1483 – 1484
[2] Langowska, K.; Kowal, J.; Palivan, C.G.; Meier, W. J. Mater. Chem. B 2014, 2, 4684.