Unveiling the Mechanisms of Enhanced Photocatalysis: A Comprehensive Study on Metal–Organic Framework Encapsulation Strategies and the Synthesis of Pt@MOF for Efficient C–N Coupling Reactions

Encapsulation of metal–organic frameworks (MOFs) presents a promising path for enhancing the photocatalytic performance of MOFs while addressing their inherent limitations. Despite the potential of this approach, there is still a lack of comprehensive studies that clarify the encapsulation process and complex photocatalytic mechanisms of these composite materials. Our investigation explores the fundamental photocatalysis principles of these composites, employing both experimental and computational methods to offer a detailed understanding that is essential for the development of future photocatalysts. In this study, we synthesized a novel photocatalyst, Pt@MOF, by combining the metal–organic framework MIL-NH2-125 (Ti) with an innovative Pt complex. The resulting Pt@MOF showed remarkable stability and photoactivity in facilitating C–N coupling reactions under mild conditions (room temperature and ambient air, λ > 440 nm). Notably, the catalyst could operate efficiently without the addition of an electron donor compound, which is typically necessary in similar reactions. Our mechanistic investigations unveiled a short, efficient electron transfer pathway from the MOF to the Pt complex facilitated by the high crystallinity of the MOF under various conditions. Remarkably, the initiation of an organic reaction occurred in the absence of any external base as an electron donor, relying instead on superoxide radicals generated through the oxidative coupling of the corresponding amines. The findings presented herein advance our understanding of MOF encapsulation strategies and pave the way for the rational design of innovative photocatalytic materials.