(PNNP)Ir catalysis at the crossroads of biomass conversion, CO2 reduction, and polyester upcycling

Abstract: The ongoing depletion of fossil fuel resources has spurred intense interest in alternative carbon-based energy and material sources, including biomass, CO2, and waste polymers, in both industrial and academic communities. Substantial efforts have therefore been devoted to biotechnology and sustainable or green technologies aimed at establishing a chemical industry in which renewable carbon resources complement diminishing fossil fuel feedstocks. These renewable resources are typically found in highly oxidized and/or oxygen-rich forms. Consequently, conventional oxidation catalysis must be fundamentally re-envisioned to enable efficient reduction and dehydration processes suitable for their chemical valorization. In this lecture, I will present the (PNNP)Ir complex as a unified and versatile catalytic platform for the reductive upgrading of biomass-derived carboxylic acid derivatives1 and CO2,2 as well as for the reductive upcycling of polyesters.3 (1) Saito, S. et al. Sci. Adv. 2020, 6, eabc0274; ACS Catal. 2022, 12, 1957. (2) Saito, S. et al. J. Am. Chem. Soc. 2020, 142, 10261; Chem. Commun. 2022, 58, 9218; Inorg. Chem. 2023, 62, 14116; Chem. Eur. J. (Concept), 2025, e202500328. (3) Saito, S. et al. Research Square (Preprint), 2026, DOI: 10.21203/rs.3.rs-8409046/v1.