{"doi":"10.1002/anie.202313744","title":"Uncovering a CF<sub>3</sub> Effect on X‐ray Absorption Energies of [Cu(CF<sub>3</sub>)<sub>4</sub>]<sup>−</sup> and Related Copper Compounds by Using Resonant Diffraction Anomalous Fine Structure (DAFS) Measurements**","abstract":"Abstract Understanding the electronic structures of high‐valent metal complexes aids the advancement of metal‐catalyzed cross coupling methodologies. A prototypical complex with formally high valency is [Cu(CF 3 ) 4 ] − ( 1 ), which has a formal Cu(III) oxidation state but whose physical analysis has led some to a Cu(I) assignment in an inverted ligand field model. Recent examinations of 1 by X‐ray spectroscopies have led previous authors to contradictory conclusions, motivating the re‐examination of its X‐ray absorption profile here by a complementary method, resonant diffraction anomalous fine structure (DAFS). From analysis of DAFS measurements for a series of seven mononuclear Cu complexes including 1 , here it is shown that there is a systematic trifluoromethyl effect on X‐ray absorption that blue shifts the resonant Cu K‐edge energy by 2–3 eV per CF 3 , completely accounting for observed changes in DAFS profiles between formally Cu(III) complexes like 1 and formally Cu(I) complexes like (Ph 3 P) 3 CuCF 3 ( 3 ). Thus, in agreement with the inverted ligand field model, the data presented herein imply that 1 is best described as containing a Cu(I) ion with d n count approaching 10.","journal":"Angewandte Chemie International Edition","year":2023,"id":335701,"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":20,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9544,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1065630,"name":"Tieyan Chang","orcid":"0000-0002-7434-3714","position":1,"is_corresponding":false},{"id":1066188,"name":"Connly Yan","orcid":null,"position":2,"is_corresponding":false},{"id":717242,"name":"Yu‐Sheng Chen","orcid":"0000-0002-7646-7761","position":3,"is_corresponding":false},{"id":415534,"name":"Neal P. Mankad","orcid":"0000-0001-6923-5164","position":4,"is_corresponding":false},{"id":1065629,"name":"Pinar Alayoglu","orcid":"0000-0003-0178-3142","position":0,"is_corresponding":true}],"reference_count":71,"raw_metadata":null,"created_at":"2026-07-19T01:10:02.777338Z","pmid":"37938103","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":[]}