Selective nitration and bromination of surprisingly ruffled phosphorus corroles

•Definition of synthetic protocols for the preparation of β-nitro phosphorus corroles•Definition of synthetic protocols for the preparation of β-bromo phosphorus corroles•The spectral properties of the functionalized corroles have been investigated.•The X-ray crystallographic structure of two derivatives has been obtained.•The ruffled conformation of these phosphorus corrole complexes has been characterized.

Phosphorus complexes of corrole have recently attracted increasing interest since these compounds can be easily prepared in good yields, are stable, and show unusual optical properties. For these reasons, phosphorus corroles represent a class of interesting compounds to be exploited in the field of material science or for biomedical investigations and the definition of synthetic pathways for their functionalization is an important step to optimize their properties for various applications. We report here the reactivity of the phosphorus complex of 5,10,15-tritolylcorrole in the nitration or bromination reaction. Both these attempts were successful, allowing the preparation of substituted phosphorus corroles, which can be used as intermediates of more complex architectures endowed with useful properties. Furthermore, the crystallographic characterization of both complexes shows that they have an unusual ruffled geometry of the corrole core, a conformation that has not been considered possible for such a macrocycle.

Graphical abstractDifferent approaches for the phosphorus corrole functionalization are reported. The results obtained demonstrate the possibility to introduce Br or nitro groups for the formation of functionalized corroles. The structural characterization of some of these corroles evidenced for the first time the possibility for this macrocycle to adopt a ruffled geometry.Figure optionsDownload full-size imageDownload as PowerPoint slide