Capture and Release of Singlet Oxygen in Coordination-Driven Self-Assembled Organoplatinum(II) Metallacycles

Abstract

Singlet oxygen ( 1 O 2 ), as an important active reagent, has found wide applications in photodynamic therapy (PDT), synthetic chemistry and materials science. Organic conjugated aromatics serving as hosts to capture and release singlet oxygen have been systematically investigated over the last decades. Herein, we present a [6+6] organoplatinum(II) metallacycle by using ~180° dipyridylanthracene donor and ~120° Pt(II) acceptor as the building blocks, which enables the capture and release of singlet oxygen with relatively high photooxygenation and thermolysis rate constants. The photooxygenation of the metallacycle to the corresponding endoperoxide was performed by sensitized irradiation, and the resulting endoperoxide is stable at room temperature and can be stored under ambient condition over months. Upon simple heating the neat endoperoxide under inert atmosphere at 120 °C for 4 h, the resulting endoperoxide can be reconverted to the corresponding parent form and singlet oxygen. The photooxygenation and thermolysis products were characterized by NMR spectroscopy and ESI-TOF-MS analysis. Density functional theory calculations were conducted in order to reveal the frontier molecular orbital interactions and reactivity. This work provides a new material-platform for singlet oxygen related promising applications.

Self-assembled metallasupramolecular cages towards light harvesting systems for oxidative cyclization

“…SCCs based on the metal–ligand interaction which is even effective at micromolar to nanomolar concentration are preferred over other host–guest or H-bonded supramolecular complexes in which interactions become ineffective upon dilution due to their low association constant in common organic solvents. 11 For the synthesis of synthetic LHSs, multiple donor molecules are required for a single acceptor, but use of multiple donors in single molecular assembly can cause fluorescence quenching by aggregation. Therefore, development of aggregation induced emissive fluorophores as donors offers an alternative in constructing efficient LHSs.…”

Anthracene-induced formation of highly twisted metallacycle and its crystal structure and tunable assembly behaviors

“…For example, Zr and Fe have been incorporated with ANTHR into coordination complexes to perform catalysis (48) and to mimic the functional behavior of enzymes (49). In addition, ANTHR-based rectangles have been proven to provide near-infrared emission for application in ammonia detection (50), and ANTHR-based hexagons have been used for the capture and release of singlet oxygen (51). However, most reported ANTHR-based metallacycles have planar structures.…”

Electron Transfer based Ultra-bright Organic Afterglow Nanoprobe for Accurate Molecular Imaging in Mice

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