Coordination entities of a pyrene-based iminopyridine ligand: Structural and photophysical properties

Abstract

A pyrene-based iminopyridine ligand L has been prepared and displays the absorption and emission properties expected for pyrene-based derivatives in solution. Ligand L, as well as two neutral and one monocationic coordination entities, respectively formulated as [ZnLCl 2 ] 1, [ReLCl(CO) 3 ] 3 and [CuL 2 ](BF 4) 2, have been crystallized and analyzed by single crystal X-ray diffraction analysis. The corresponding crystal structures indicate the formation of supramolecular architectures generated by offset π•••π stacking between pyrene fragments and strong C-H•••π interactions in coordination entity 1. For the cationic coordination entity 2, the crystal packing reveals the presence of C-H•••F and C-H•••π interactions and numerous C-H•••π contacts interconnecting the molecules into a 3D network. As for coordination entity 3, hydrogen bonding and π•••π stacking link the molecules in a three dimensional manner. Zinc (II) and copper (I) coordination entities have also been studied through isothermal titration calorimetry, which indicate a strong binding and a different stoichiometry for both coordination entities. Photophysical studies of the ligand and corresponding coordination entities show a monomer type pyrene emission and a higher fluorescence quantum yield for the zinc coordination entity 1 as compared with copper 2 and rhenium 3 coordination entities.

NiII, PdII Complexes with Pyrene‐based Thiosemicarbazones: Syntheses, Molecular Structures, and Excimeric Emissions

“…The design of bis‐pyrenyl chemosensors has been mainly based on a wide range of organic linkages . Nonetheless, the use of coordinating scaffold in designing bis‐pyrenyl chemosensors are little explored . For example, a tetracarbonyl diruthenium complex with pyrenyl groups coordinated in equatorial positions was demonstrated to act as molecular tweezer for fullerene .…”

“…[4] Nonetheless, the use of coordinating scaffold in designing bis-pyrenyl chemosensors are little explored. [5] For example, a tetracarbonyl diruthenium complex with pyrenyl groups coordinated in equatorial positions was demonstrated to act as molecular tweezer for fullerene. [6] Recently, Yip reported Ag I /Cu I metallacyclophanes with (diphenylphosphanyl)pyrene ligands which displayed strong excimeric emission.…”