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Bresciani G, Ciancaleoni G, Zacchini S, Biancalana L, Pampaloni G, Funaioli T, Marchetti F. Mixed valence triiron complexes from the conjugation of [Fe IFe I] and [Fe II] complexes via intermolecular carbyne/alkyne coupling. Dalton Trans 2024; 53:4299-4313. [PMID: 38345429 DOI: 10.1039/d4dt00079j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
We present a new synthetic strategy for obtaining mixed-valence triiron complexes where the metal centers are bridged by a novel, highly functionalized hydrocarbyl ligand. The alkynyl-vinyliminium complexes [Fe2Cp2(CO)(μ-CO){μ-η1:η3-C(X-CCH)CHCNMe2}]CF3SO3 (X = 4-C6H4, [2a1]CF3SO3; X = (CH2)3, [2a2]CF3SO3) were synthesized in almost quantitative yields from the aminocarbyne precursor [Fe2Cp2(CO)2(μ-CO){μ-CNMe2}]CF3SO3, [1a]CF3SO3, and the di-alkynes HCC-X-CCH. Then, the ferracycle [Fe(Cp)(CO){C(NMe2)CHC(4-C6H4CCH)C(O)}], 4a1, was produced in 47% yield from the cleavage of [2a1]CF3SO3 promoted by pyrrolidine. Subsequent reactions of the acetonitrile adducts [Fe2Cp2(CO)(μ-CO)(NCMe){μ-CNMe(R)}]CF3SO3 (R = Me, [1aACN]CF3SO3; R = Xyl, [1bACN]CF3SO3) ([FeIFeI]) with 4a1 ([FeII]) at room temperature resulted in the formation of [FeIFeIFeII] complexes [Fe2Cp2(CO)(μ-CO){μ-η1:η3-C(X-CCHC(NMe2)FeCp(CO)CO)CHCNMe(R)}]CF3SO3 (R = Me, [5a1]CF3SO3; R = Xyl, [5b1]CF3SO3) in yields ranging from 56% to 64%. The new products were characterized by IR and multinuclear NMR spectroscopy, and the structures of [2a2]CF3SO3 and 4a1 were confirmed by single crystal X-ray diffraction. Cyclic voltammetry and spectroelectrochemical studies on [5a1]+ have revealed that reduction and oxidation events occur almost independently at the [FeIFeI] and [FeII] units, respectively. This observation underscores a minimal electronic interaction between the two fragments within the triiron complex. Accordingly, DFT studies pointed out that the HOMO and LUMO orbitals are predominantly localized in the two distinct compartments of [5a1]+.
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Affiliation(s)
- Giulio Bresciani
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, I-56124 Pisa, Italy.
- CIRCC, Via Celso Ulpiani 27, I-70126 Bari, Italy
| | - Gianluca Ciancaleoni
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, I-56124 Pisa, Italy.
- CIRCC, Via Celso Ulpiani 27, I-70126 Bari, Italy
| | - Stefano Zacchini
- University of Bologna, Department of Industrial Chemistry "Toso Montanari", Viale Risorgimento 4, I-40136 Bologna, Italy
- CIRCC, Via Celso Ulpiani 27, I-70126 Bari, Italy
| | - Lorenzo Biancalana
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, I-56124 Pisa, Italy.
- CIRCC, Via Celso Ulpiani 27, I-70126 Bari, Italy
| | - Guido Pampaloni
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, I-56124 Pisa, Italy.
- CIRCC, Via Celso Ulpiani 27, I-70126 Bari, Italy
| | - Tiziana Funaioli
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, I-56124 Pisa, Italy.
- CIRCC, Via Celso Ulpiani 27, I-70126 Bari, Italy
| | - Fabio Marchetti
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, I-56124 Pisa, Italy.
- CIRCC, Via Celso Ulpiani 27, I-70126 Bari, Italy
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Rojo-Gómez EG, Munguía-Lara AI, González-Abrego DO, Sánchez-Cabrera G, Alvarado-Rodríguez JG, Hernández-Cruz MG, Rosales-Hoz MJ, Leyva MA, Carrasco AL, Andrade-López N, Zuno-Cruz FJ. Reactivity and structural patterns of phenylphosphines in acetylene and acetylide carbonyl trinuclear ruthenium clusters. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.01.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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