{"doi":"10.1021/jacs.0c06570","title":"Selective, High-Temperature O <sub>2</sub> Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks","abstract":"Developing O2-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that chemically reduced metal–organic framework materials of the type AxFe2(bdp)3 (A = Na+, K+; bdp2– = 1,4-benzenedipyrazolate; 0 < x ≤ 2), which feature coordinatively saturated iron centers, are capable of strong and selective adsorption of O2 over N2 at ambient (25 °C) or even elevated (200 °C) temperature. A combination of gas adsorption analysis, single-crystal X-ray diffraction, magnetic susceptibility measurements, and a range of spectroscopic methods, including 23Na solid-state NMR, Mössbauer, and X-ray photoelectron spectroscopies, are employed as probes of O2 uptake. Significantly, the results support a selective adsorption mechanism involving outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the structure. We further demonstrate O2 uptake behavior similar to that of AxFe2(bdp)3 in an expanded-pore framework analogue and thereby gain additional insight into the O2 adsorption mechanism. The chemical reduction of a robust metal–organic framework to render it capable of binding O2 through such an outer-sphere electron transfer mechanism represents a promising and underexplored strategy for the design of next-generation O2 adsorbents.","journal":"Journal of the American Chemical Society","year":2020,"id":60987,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":59,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9516,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":322375,"name":"Michael E. Ziebel","orcid":"0000-0003-1857-8292","position":1,"is_corresponding":false},{"id":322376,"name":"David M. Halat","orcid":"0000-0002-0919-1689","position":2,"is_corresponding":false},{"id":322377,"name":"Naomi Biggins","orcid":"0000-0002-4132-6395","position":3,"is_corresponding":false},{"id":322378,"name":"Ryan A. Murphy","orcid":"0000-0002-3695-2295","position":4,"is_corresponding":false},{"id":270876,"name":"Khetpakorn Chakarawet","orcid":"0000-0001-5905-3578","position":5,"is_corresponding":false},{"id":228307,"name":"Jeffrey A. Reimer","orcid":"0000-0002-4191-3725","position":6,"is_corresponding":false},{"id":228309,"name":"Jeffrey R. Long","orcid":"0000-0002-5324-1321","position":7,"is_corresponding":false},{"id":322374,"name":"Adam Jaffe","orcid":"0000-0002-9886-0249","position":0,"is_corresponding":true}],"reference_count":60,"raw_metadata":null,"created_at":"2026-07-18T21:09:27.985420Z","pmid":"32786654","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}