Crystal structure, host-guest interactions and supramolecular features of a novel μ-hydroxy bridged eclipsed dimer based on indium(III) tetrapyrazinoporphyrazine

Abstract

The crystal structure of the indium(III) derivative of a chloro-substituted tetrapyrazinoporphyrazine (TPyzPz), which is dimerized through hydroxy bridges is reported. The In(III) ion resides well outside the mean plane of the distorted pyrazinoporphyrazine core and thus each TPyzPz fragment has a domed shape. Two axial hydroxy groups are coordinated to the indium ions of two adjacent In(III) tetrapyrazinoporphyrazine fragments to form a co-facial dimer (InTPyzPz) which are eclipsed in geometry. Each indium(III) is six coordinated and the whole molecule is neutral in charge. Four pyridine molecules are encapsulated between TPyzPz fragments in the dimer, thereby forming a stable host-guest system. The host-guest interactions between the TPyzPz and pyridines are achieved by efficient O-H...N and [Formula: see text]...[Formula: see text] type nonbonding interactions. The packing pattern of the crystal shows that the InTPyzPz system formed a herringbone-type assembly in its network. A combination of multiple Cl...Cl, C-H...O, and C-H...[Formula: see text] and interactions between adjacent TPyzPz have been observed which in turn favored and stabilized this supramolecular network. The dimeric InTPyzPz system is further studied by the Hirshfeld Surfaces analysis which also indicated significant nonbonding interactions in the crystal and the related 2D fingerprint plots provided a quantitative idea of the inter-atomic interactions among the adjacent dimers.