{"doi":"10.1021/om990119k","title":"Structure and Reactivity of η<sup>2</sup>(3e)-Nitrile and η<sup>2</sup>(3e)-Alkyne Complexes of Niobium","abstract":null,"journal":"Organometallics","year":1999,"id":685419,"datarank":0.5416376868966337,"base_score":3.6109179126442243,"endowment":3.6109179126442243,"self_citation_contribution":0.5416376868966337,"citation_network_contribution":0.0,"self_endowment_contribution":0.5416376868966337,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":36,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1790702,"name":"Carla Carfagna","orcid":null,"position":1,"is_corresponding":false},{"id":1790703,"name":"Philippe Lorente","orcid":null,"position":2,"is_corresponding":false},{"id":1790704,"name":"René Mathieu","orcid":null,"position":3,"is_corresponding":false},{"id":1790705,"name":"Dominique de Montauzon","orcid":null,"position":4,"is_corresponding":false},{"id":1790701,"name":"Michel Etienne","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Structure and Reactivity of η<sup>2</sup>(3e)-Nitrile and η<sup>2</sup>(3e)-Alkyne Complexes of Niobium","abstract":"Nitrile adducts of the type Tp*Nb(CO)(PhC⋮CMe)(RC⋮Ν) (Tp* = hydridotris(3,5-dimethylpyrazolyl)borate; R = Me ( 2a ), Et ( 2b ), PhCH 2 ( 2c ), 4-MeOC 6 H 5 ( 2d ), Ph ( 2e ), 4-CF 3 C 6 H 5 ( 2f )) have been prepared in fair yields by CO displacement from Tp*Nb(CO) 2 (PhC⋮CMe) ( 1 ) and fully characterized. 13 C NMR spectroscopy (δ 180−190 for the nitrile and alkyne contact carbons) and X-ray crystallography (for 2b ) indicate an η 2 -coordination and an unprecedented formally three-electron-donor (3e) behavior for both the alkyne and the nitrile. Electrochemical studies suggest that an equilibrium between this η 2 (3e)-nitrile/η 2 (3e)-alkyne form and an otherwise undetected η 1 (2e)-nitrile/η 2 (4e)-alkyne form exists in solution. PhC⋮N is thermally displaced from 2e by PMe 2 Ph or PhC⋮CMe to give Tp*Nb(CO)(PhC⋮CMe)(PMe 2 Ph) or Tp*Nb(CO)(PhC⋮CMe) 2 ( 3a ), respectively. 3a does not react with PMe 2 Ph. Protonation of 2b with HBF 4 induces nitrile/alkyne coupling to give the niobacycle Tp*NbF(CPhCMeCPhNH), via the isolated η 2 -iminoacyl alkyne cation [Tp*Nb(CO)(η 2 -CPh NH)(PhC⋮CMe)][BF 4 ], characterized by NMR spectroscopy at 243 K. Protonation of 3a with HBF 4 leads to the niobacycle Tp*NbF[C(Ph)C(Me)C(CMe CPhH)O] (X-ray structure), in which CO is included in the alkyne coupling reaction. The intermediate [Tp*Nb(CO)(CMe CPhH)(PhC⋮CMe)][BF 4 ] has been characterized by NMR at 193 K. A deshielded C α (δ 205), a shielded C β (δ 97), and a reduced 1 J CH (114 Hz) suggest that a β-CH agostic interaction stabilizes this vinyl alkyne cation. Protonation of the new phosphinoalkyne derivative Tp*Nb(CO)(PhC⋮CMe)(PPh 2 C⋮CPh) affords the stable phosphonium complex {Tp*Nb(CO)[Ph 2 P(H)C⋮CPh](PhC⋮CMe)}[BF 4 ], in which the two alkyne ligands act as 3e donors.","is_dataset_classified":null,"base_score":3.6109179126442243,"endowment":3.6109179126442243,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"26207759","pmcid":null,"openalex_id":"https://openalex.org/W2037668748","authors":[],"funders":[],"total_grants":0,"fwci":1.6323,"citation_percentile":0.80160271,"influential_citations":0,"citation_trend":[{"year":2012,"count":1},{"year":2013,"count":1},{"year":2014,"count":1},{"year":2015,"count":2},{"year":2016,"count":2},{"year":2020,"count":1},{"year":2022,"count":1}],"oa_status":"closed","license":null,"oa_locations":[{"url":"https://pubs.acs.org/doi/pdf/10.1021/om990119k","host_type":"publisher"},{"url":"https://doi.org/10.1021/om990119k","host_type":"journal"}],"fields_of_study":["Organometallic Complex Synthesis and Catalysis","Synthetic Organic Chemistry Methods","Synthesis and characterization of novel inorganic/organometallic compounds"],"mesh_terms":[],"keywords":["Alkyne","Nitrile","Chemistry","Protonation","Medicinal chemistry","Nuclear magnetic resonance spectroscopy","Stereochemistry","Crystallography","Organic chemistry","Catalysis"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Clean water and sanitation"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-18T16:37:49.182116Z","pmid":null,"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":[]}