Bioinspired Polypeptoid-driven Microenvironment Engineering for Enhanced Sn (Ⅳ)-Catalyzed Biomass Conversion

5-Hydroxymethylfurfural (HMF) is an important platform molecule for the sustainable production of biomass-derived fine chemicals and pharmaceuticals. However, the efficient conversion of abundant six-carbon sugars to HMF under mild conditions requires catalysts with exceptional activity and selectivity. Herein, we report a multifunctional heterogeneous catalyst composed of a carboxyl-functionalized polypeptoid and Sn 4+ (Sn/PG-COOH), which significantly improved both the catalytic activity and selectivity for the one-pot conversion of glucose to HMF. The carboxylated polypeptoid matrix serves as an ideal platform for integrating Lewis acid centers (e.g., Sn 4+ ), which are stably confined by steric hindrance and coordination with the polypeptoid. The flexible carboxyl-functionalized polymeric backbone dynamically modulates the electron density of Sn 4+ via the donor–acceptor effect, thereby optimizing its interaction energy with substrates to regulate the electronic microenvironment. This generates uniformly distributed Lewis acid sites and hydrophobic active sites, resulting in an HMF yield of up to 58.1% at a glucose conversion of 96.3% at a mild temperature of 150 °C, which represents a 1.6-fold increase over that using C-SnO 2 . Further, density-functional theory calculations were employed to probe the electron density profile of Sn 4+ under polypeptoid modulation, providing theoretical insights into the polymer-modulated electronic microenvironment. This work presents a promising strategy for the rational design of advanced multifunctional catalysts, demonstrating that Sn/PG-COOH is a highly efficient and selective catalyst for the glucose-to-HMF transformation. Multifunctional Sn/PG-COOH catalyst: The polypeptoid matrix confines Sn 4+ via steric hindrance/coordination and modulates its electron density through the donor–acceptor effect, forming uniform Lewis acid/hydrophobic sites, thus enabling glucose-to-HMF conversion (96.3% conversion, 58.1% yield). DFT elucidates the polymer-modulated electronic microenvironment and supports the rational design of efficient catalysts.