From Coordination to π-Hole Chemistry of Transition Metals: Metalloporphyrins as a Case of Study.

Herein we have evidenced the formation of favorable π-hole Br⋅⋅⋅metal noncovalent interactions (NCIs) involving elements from groups 9, 11 and 12. More in detail, M (M=Co, Ni, Cu and Zn) containing porphyrins have been synthesized and their supramolecular assemblies structurally characterized by means of single crystal X-ray diffraction and Hirshfeld surface analyses, revealing the formation of directional Br⋅⋅⋅M contacts in addition to ancillary hydrogen bond and lone pair-π bonds. Computations at the PBE0-D3/def2-TZVP level of theory revealed the π-hole nature of the Br⋅⋅⋅M interaction.

Electrochemical, Photophysical, Morphological and DFT Study of Polymorphic Sn(IV)-Porphyrins Containing Fluorinated Axial Ligand.

In this study, we report the polymorphism of six coordinated Sn(IV)- tetrabromophenyl porphyrins axially armed with fluorine-substituted phenolate ligands (structural formula [Sn(TBrPP) (A ) ], where A is the axial ligand=3,5-difluoro phenol, compound 1). One form stabilizes in triclinic system (namely, 1α), and the other stabilizes in monoclinic system (namely, 1β). The two 1α and 1β polymorphs display distinct photophysical and morphological properties in the solid state.

Computational insight into the halogen bonded self-assembly of hexa-coordinated metalloporphyrins.

We demonstrate herein a computational study probing the influence of metalloporphyrins on intermolecular halogen bonding (XB) during supramolecular self-assembly. The results demonstrate that porphyrin aromatic rings can activate or deactivate halogen bonding interactions, especially those on axial ligands, and further influence the preference type of halogen···halogen bonding during the supramolecular self-assembly. Calculations show that the halogen atom present at the equatorial position has a higher sigma hole potential (V) than that at the axial position.