Organoboron-Functionalized Metal-Organic Nanosheets for Highly Efficient CO2 Fixation Mediated by Frustrated Lewis Pairs

Converting CO₂ to high-value fine chemicals represents one of the most promising approaches to combat global warming and subsequently achieve a sustainable carbon cycle. Herein, we contribute an organoboron functionalized ultra-thin metal-organic nanosheet (MON), termed TCPB-Zr-NS, featuring an abundance of exposed Lewis acidic B and formate sites, which can effectively promote CO₂ conversion upon the addition of Lewis basic o-phenylenediamines. Compared with the prototypical 3D analogue TCPB-Zr-3D, the resultant TCPB-Zr-NS showcases dramatically improved catalytic activity for the cyclization of o-phenylenediamine as a result of the highly exposed active sites and efficient substrates/products diffusion. Strikingly, the incorporation of Lewis acidic B sites into ultra-thin Zr-based MON (Zr-MON) not only promotes the highly efficient CO₂ conversion, but also enhances the recyclability/durability of catalysts. Additionally, the underlying catalytic mechanism has been well established by the comprehensive experiments and theoretical calculations, unveiling a formate-assisted frustrated Lewis pairs (FLP) mediated catalytic pathway. This work opens up a new avenue to heterogeneous FLP-based catalysts for small molecule activation and beyond.