Effect of substitutions on the geometry and intramolecular hydrogen bond strength in meta-benziporphodimethenes: A new porphyrin analogue

Abstract

A new class of compound meta-benziporphodimethene, that has low synthetic yield yet extensive applications in metal ion sensing and cell-imaging, has been explored here. The present work is aimed to investigate the effect of substituents at sp2 and sp3meso carbons, on the geometry and energy of these molecules. The substitution at these positions affects the inner geometry (cavity size) and the classical hydrogen bond strengths. The hydrogen bond strength has been estimated using molecular tailoring-based approach using density functional theory. Theoretical studies showed that on increasing the bulkiness of sp3meso positions, the puckered structure undergoes better conventional hydrogen bonding. It is also concluded that electron-withdrawing groups at sp2meso phenyl stabilize the molecule more than electron-donating ones. This study is useful for perceiving the factors regulating the cavity size in meta-benziporphodimethene analogs that can further enhance the ease in metalation of these moieties.