A study of the reactivity of a T-shaped iron(I) complex supported by a carbazole-based PNP pincer ligand () has established its strongly reducing character and propensity to bind small molecules with concomitant transfer of charge and spin density. Metalloradical reactivity was observed in the reaction with the stable radical 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) yielding the corresponding Fe hydroxylaminato complex . Complex reacted rapidly and selectively with two molecules of carbon monoxide to give the corresponding low-spin dicarbonyl complex . When reacted with phenylacetylene, the alkyne complex was isolated in which the alkyne was found to bind side-on as an η-ligand, which adopts radical anion character as a result of charge transfer from the metal center. Reaction with diphenyl diazomethane generated an adduct in which the diazoalkane also appears to be partially reduced and acquires radical character. Upon exposure to carbon dioxide, oxygen atom abstraction was observed, ultimately leading to the isolation of the monocarbonyl iron(I) complex and a dinuclear carboxylato ferrous complex . Furthermore, reaction with chalcogen atom transfer reagents resulted in the formation of the corresponding dinuclear ferrous chalcogenido compounds (E = S (), Se ()), which were found to display strong antiferromagnetic coupling (, = -68 cm; : = -58 cm).
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http://dx.doi.org/10.1021/acs.inorgchem.0c03724 | DOI Listing |
J Am Chem Soc
October 2024
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.
Iron cyanide compounds are among the oldest known synthetic coordination compounds, dating back to the early 18 century. By contrast, iron complexes of the cyaphide ion (C≡P)─a heavy valence isoelectronic analog of the cyanide ion─are unknown. Herein we report the synthesis of highly stable mono- and bis-cyaphide complexes of iron(II), namely Fe(depe)(Cl)(CP) and Fe(depe)(CP) (depe = 1,2-bis(diethylphosphino)ethane).
View Article and Find Full Text PDFInorg Chem
October 2024
Catalysis Research Laboratory (CaRLa), Heidelberg University, Im Neuenheimer Feld 584, 69120 Heidelberg, Germany.
The search for an iron analog of the established ruthenium-based catalysts containing methylene-extended 4,5-bis(diorganophosphinomethyl)acridine ligands, [FeHCl(CO)(L)], resulted in the discovery of a bidentate coordination mode of these usually tridentate pincer ligands toward iron. The acridines nitrogen atom does not coordinate to iron, leading to the formation of iron diphos-type complexes with unusually large bite angles of up to 124° as well as bite angles around 155°. The iron-containing complexes [FeCl(κ-L)] (R = Pr, Ph), [FeX(κ-L)] (X = Cl, Br) and [Fe(CO)(κ-L)] (R = Pr, Cy) have been isolated in crystalline form and characterized by spectroscopic methods and mass spectrometry.
View Article and Find Full Text PDFDalton Trans
October 2024
School of Chemistry and Chemical Engineering, Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Shanda Nanlu 27, 250100 Jinan, People's Republic of China.
In this contribution, Co(PMe)Cl (1), bis(silylene) cobalt chlorides Co(LSi:)(PMe)Cl (LSi: = {PhC(NBu)}SiCl (2); {-CHCHC(NBu)}SiCl (3); and {-BuCHC(NBu)}SiCl (4)) and bis(silylene) iron chlorides Fe(LSi:)(PMe)Cl (LSi: = {PhC(NBu)}SiCl (5); {-CHCHC(NBu)}SiCl (6); {-BuCHC(NBu)}SiCl (7) and Fe(PMe)Cl (8)) were synthesized to study the effects of different metals and silylene ligands on the catalytic activity of complexes 1-8 in dinitrogen silylation reaction. The experimental results indicate that there is no substantial difference in catalytic activity between the phosphine cobalt complex 1 and the silylene cobalt chlorides 2-4 although the cobalt silylene complex 2 has slightly better catalytic activity than complexes 1, 3 and 4 in the dinitrogen silylation. Silylene iron complexes 5-7 are more active than the phosphine iron complex 8.
View Article and Find Full Text PDFOrg Lett
September 2024
School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
The use of an earth-abundant and inexpensive iron complex as a catalyst, coupled with near-infrared (NIR) light as the energy source, for radical reactions with alkyl halides has been far less developed. In this study, we report NIR light-mediated iron(I) dimer-catalyzed radical cascade reactions of fluoroalkyl bromides for the synthesis of ring-fused quinazolinones bearing a difluoromethyl group. In this process, the 3-bromo-1,10-phenanthroline ligand facilitates the reactivity of [CpFe(CO)], thereby improving the efficiency of the reaction.
View Article and Find Full Text PDFInorg Chem
September 2024
Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States.
UV irradiation of yellow CHCl solutions of -Fe(CO)(P((CH))P) () and PMe (10 equiv) gives, in addition to the previously reported dibridgehead diphosphine P((CH))P (46%), a green paramagnetic complex that crystallography shows to be the trigonal-bipyramidal iron(I) radical -[Fe(CO)(Cl)(P((CH))P)] (; 31% after workup). This is a rare example of an isolable species of the formula [Fe(CO)(L)(X)] ( = 0-3, L = two-electron-donor ligand; X = one-electron-donor ligand). Analogous precursors with longer P(CH)P segments ( = 12, 14, 16, 18) give only the demetalated diphosphines, and a rationale is proposed.
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