Pi-Extended 2D-Networks of Heteroaromatic Compounds - Towards Two-Dimensional Nanostructured Materials

Graphene and other two-dimensional (2D) materials such as inorganic transition metal dichalchogenides (TMDs) represent key nanostructural materials for use in a range of functional devices including gas and biosensors. The functionalization of nanomaterials is a critical factor for tailoring their surface properties, enhancing their potential applicability in optoelectronics and catalysis to name but a few. Porphyrins can easily be used for the construction of π-extended systems using well-established synthetic chemistry methodologies. [1] These range from organometallic C-C bond forming reactions to introduce tailored substituents at the porphyrin periphery and the construction of porphyrin arrays connected conjugated linkers, to porphyrin tape-like oligomers through oxidative meso-meso and meso-β-fusing reactions. The selective functionalization of these heteroaromatic systems now opens the possibility to combine them with carbon-based aromatic systems to yield mixed π-extended systems with unique photophysical properties. Present studies reveal the emergence of a surface chemistry of such systems where specific reactions, e.g., metallation, remetallation and C-C–coupling can be induced on surfaces. [2] Surface/macrocycle interactions alter the chemical properties of porphyrins and the adsorption of tailored macrocycles onto 2D surfaces could generate novel platform systems for, e.g., the attachment of biomarkers for use as biosensors. Additionally, TMDs, e.g., MoS₂, represent a growing area of research due to their fascinating electronic and optoelectronic properties. [3] Through chemical modification of these surfaces it is hoped that attachment of large heteroaromatic systems will further tailor these materials for functional use.

References

[1] A. A. Ryan, M. O. Senge Eur. J. Org. Chem. 3700 (2013).

[2] S. Krasnikov, C. Doyle, N. Sergeeva, A. Preobrajenski, N. Vinogradov, Y. Sergeeva, A. Zakharov, M. Senge, A. Cafolla Nano Res. 4, 376 (2011).

[3] G. S. Duesberg Nat. Mater. 13, 1075 (2014).