Platinum(II) based macrocyclic host for recognition of aromatic hydrocarbons

Abstract

A platinum(II) based macrocycle [Pt2(bpy)2(L)2](NO3)4 1, has been synthesized and characterized by NMR and ESI-MS. Single crystal X-ray diffraction study reveals that the macrocycle possesses a well-defined cavity. Hirshfeld calculation reveals that complex 1 is extensively engaged in intermolecular π-π stacking in the crystal lattice. The molecular cavity described by 1 is large enough for encapsulation of comparable size guest molecules. X-ray diffraction study on the single crystals obtained by diffusion of various aromatic molecules confirms the encapsulation of benzene and m-xylene inside the cavity of macrocycle 1. Further, molecular docking shows that the macrocycle complex 1 can also encapsulate polyaromatic hydrocarbons such as naphthalene and anthracene along with benzene and m-xylene. Pyrene being a bulkier polyaromatic hydrocarbon was partly encapsulated inside the cavity of 1. The binding energy for the encapsulated complexes 1⊃benzene, 1⊃toluene, 1⊃m-xylene, 1⊃naphthalene, 1⊃anthracene and 1⊃pyrene obtained from docking study is found to be -3.48, -3.90, -4.25, -5.03, -6.19 and -5.38 kJ/mol respectively. © 2023 Elsevier B.V.