Spectroscopic Investigation of Bianthryl Based Metal Organic Framework Thin Films and Their Photoinduced Topotactic Transformation

Metal organic frameworks MOFs have gained a large amount of interest because of their periodic and modular structure. These features allow easy prediction of the physical and chemical properties of an organic chromophore, acting as a linker in the MOF. In the present work, a bianthryl BA chromophore, equipped with metal coordinating carboxylate groups, is studied to construct a photoluminescent Zn BA surface anchored MOF SURMOF thin film. The Zn BA SURMOF, in response to prolonged UV light irradiation under ambient conditions, exhibits prominent changes in the ground and excited state optical properties, without losing its crystalline structure. A detailed spectroscopic study using UV vis, infra red, Raman, and electron paramagnetic resonance EPR reveals that in the presence of O2 a photoinduced topotactic transformation is initiated by the formation of singlet oxygen, which then reacts with the BA linkers to form endoperoxid