Water encapsulation in porphyrin-crown ether conjugate: X-ray, Hirshfeld, and V_bur Analysis

Supramolecular chemistry has facilitated the development of advanced functional materials through precise non-covalent interactions. Porphyrins, known for their unique optical, electronic, and photophysical properties, are particularly useful in catalysis, sensing, and biomedical applications. This study examines the X-ray crystal structure of a porphyrin derivative functionalized with four 18-crown-6 groups (PTC), synthesized via Suzuki–Miyaura coupling. The single-crystal X-ray diffraction reveals the encapsulation of a water molecule within the porphyrin cavity, a notable structural feature. The planar structure of PTC is stabilized by hydrogen bonds between pyrrole NH groups and the trapped water molecule. The average N-N bond length is 2.923 Å, slightly longer than reported previously, while the macrocycle remains undistorted. Hirshfeld surface analysis (HSA) and V bur calculations offer insights into intermolecular interactions and steric effects, showing dominant H[Formula: see text]H contacts (57.9%), along with significant H[Formula: see text]C/C[Formula: see text]H (20.4%) and H[Formula: see text]O/O[Formula: see text]H (10.3%) interactions. The %V bur of 64.5% indicates a crowded steric environment around the porphyrin core. These findings highlight the potential of crown-functionalized porphyrins in molecular recognition, catalysis, and supramolecular assemblies, advancing our understanding of host-guest interactions and opening new pathways in supramolecular chemistry and nanomaterials.