{"doi":"10.1039/d0dt04436a","title":"Mechanistic insight into oxygen atom transfer reactions by mononuclear manganese( <scp>iv</scp> )–oxo adducts","abstract":"High-valent metal-oxo intermediates are well known to facilitate oxygen-atom transfer (OAT) reactions both in biological and synthetic systems. These reactions can occur by a single-step OAT mechanism or by a stepwise process initiated by rate-limiting electron transfer between the substrate and the metal-oxo unit. Several recent reports have demonstrated that changes in the metal reduction potential, caused by the addition of Brønsted or Lewis acids, cause a change in sulfoxidation mechanism of MnIV-oxo complexes from single-step OAT to the multistep process. In this work, we sought to determine if ca. 4000-fold rate variations observed for sulfoxidation reactions by a series of MnIV-oxo complexes supported by neutral, pentadentate ligands could arise from a change in sulfoxidation mechanism. We examined the basis for this rate variation by performing variable-temperature kinetic studies to determine activation parameters for the reactions of the MnIV-oxo complexes with thioanisole. These data reveal activation barriers predominantly controlled by activation enthalpy, with unexpectedly small contributions from the activation entropy. We also compared the reactivity of these MnIV-oxo complexes by a Hammett analysis using para-substituted thioanisole derivatives. Similar Hammett ρ values from this analysis suggest a common sulfoxidation mechanism for these complexes. Because the rates of oxidation of the para-substituted thioanisole derivatives by the MnIV-oxo adducts are much faster than that expected from the Marcus theory of outer-sphere electron-transfer, we conclude that these reactions proceed by a single-step OAT mechanism. Thus, large variations in sulfoxidation by this series of MnIV-oxo centers occur without a change in reaction mechanism.","journal":"Dalton Transactions","year":2021,"id":181854,"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":15,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9592,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":733455,"name":"Eleanor Stewart-Jones","orcid":"0000-0002-7786-5446","position":1,"is_corresponding":false},{"id":733456,"name":"Melissa C. Denler","orcid":"0000-0003-2443-6178","position":2,"is_corresponding":false},{"id":475821,"name":"Timothy A. Jackson","orcid":"0000-0002-3529-2715","position":3,"is_corresponding":false},{"id":733454,"name":"Priya Singh","orcid":"0000-0002-8529-3839","position":0,"is_corresponding":true}],"reference_count":63,"raw_metadata":null,"created_at":"2026-07-18T23:48:09.223560Z","pmid":"33616141","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":[]}