Alkylidyne and Alkylidene Complexes of Iron

Marchetti, Fabio

doi:10.1016/b978-0-12-820206-7.00105-0

Cited by 7 publications

(12 citation statements)

References 218 publications

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“…Isocyanide ligands in transition-metal complexes may be prone to the addition of electrophiles to form the corresponding aminocarbyne ligands. ,,,, In general, the Lewis basicity of the nitrogen atom is enhanced on increasing the electron π back-donation from the metal center(s) to the isocyanide; therefore, in dinuclear complexes, the bridging coordination may be crucial to permit the conversion into aminocarbyne. − …”

Section: Resultsmentioning

confidence: 99%

“…Isocyanide ligands in transition-metal complexes may be prone to the addition of electrophiles to form the corresponding aminocarbyne ligands. 20,32,43,58,59 In general, the Lewis basicity of the nitrogen atom is enhanced on increasing the electron π backdonation from the metal center(s) to the isocyanide; therefore, in dinuclear complexes, the bridging coordination may be crucial to permit the conversion into aminocarbyne. 60−64 In light of the presence of a bridging isocyanide ligand in the neutral complexes 2a−c, we moved to investigate their reactivity with an easily available alkylating agent such as methyl triflate.…”

Section: Carbon Monoxide-isocyanide Substitution Reactionmentioning

confidence: 99%

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Construction of Two-Faced (Hetero)hydrocarbyl Diiron Complexes Mediated by the Interplay of Ligands

et al. 2023

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The functionalized allylidene complex [Fe 2 Cp 2 (CO)(μ-CO){μ-η 1 :η 3 -C γ (Fc)-C β HC α (CN)NMe 2 }], 1 [Cp = η 5 -C 5 H 5 ; Fc = CpFe(η 5 -C 5 H 4 )], reacted with isocyanides (CNR), in isopropanol solution at ca. 100 °C, to give the CO-substitution products [Fe 2 Cp 2 (CO)(μ-CNR){μ-η 1 :η], which were isolated in 61−84% yields. The bridging coordination of CNR in 2a−c is forced by a stabilizing electrostatic interaction between the nitrogen lone pair belonging to the {NMe 2 } group and the terminal CO ligand. Isocyanide methylation with methyl triflate proceeded with the inversion of stereochemistry at the C α carbon and led to [Fe 2 Cp 2 (CO){μ-CN(Me)R}{μ-η 1 :η), containing bridging allylidene and aminocarbyne ligands (68−74% yields). All products were fully characterized by IR and multinuclear NMR spectroscopy, and the structures of 2a and [3a]CF 3 SO 3 were elucidated by X-ray diffraction studies. Density functional theory (DFT) calculations were extensively carried out to shed light on structural, mechanistic, and thermodynamic features.

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Section: Resultsmentioning

confidence: 99%

Section: Carbon Monoxide-isocyanide Substitution Reactionmentioning

confidence: 99%

Construction of Two-Faced (Hetero)hydrocarbyl Diiron Complexes Mediated by the Interplay of Ligands

et al. 2023

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“…However, NMR signals due to each isomer could not be unambiguously assigned. Salient 13 C NMR features are given by the resonance of the aminocarbyne carbon, which falls at typical low fields (327.6-335.9 ppm), [38,[55][56][57] and the resonance due to the cyano moiety, occurring at about 120 ppm. The identity of 3a-b was further corroborated by ESI-MS spectra, showing the peak due to the molecular cation.…”

Section: Synthesis and Characterization Of Complexesmentioning

confidence: 99%

“…[40] The C(3)-N(1) bond (1.273(10) Å) possesses some double bond character, as routinely found in related diiron μ-aminocarbyne complexes. [38,40,55]…”

Section: Synthesis and Characterization Of Complexesmentioning

confidence: 99%

“…The preferential occupancy of terminal sites by aminoalkylidene ligands in diiron bis-cyclopentadienyl complexes was previously established. [55,73] A hydride might then migrate from [cis-t3eH] À to the cyclohexanone (a suitable TS has not been found), giving the complex cis-t3e/cyclohexanoxide (cis-PC, ΔH = 17.8 kcal mol À1 ), see red path in Figure 4. This can return to its more stable isomer, trans-3e, and cyclohexanone (ΔH = À0.7 kcal mol À1 ).…”

Section: Dft Calculationsmentioning

confidence: 99%

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Diiron bis‐cyclopentadienyl complexes as transfer hydrogenation catalysts: The key role of the bridging aminocarbyne ligand

Bresciani

Biancalana

Zacchini

et al. 2022

Applied Organom Chemis

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The catalytic activity of a series of diiron complexes based on the {Fe 2 Cp 2 (CO) x } core (x = 2-3) and containing a bridging aminocarbyne ligand was screened in transfer hydrogenation reaction of cyclohexanone from isopropanol. The series includes cationic tricarbonyl complexes, [1a-d]CF 3 SO 3 , and neutral derivatives obtained by substitution of one carbonyl with hydride (2a-c), cyanide (3a-d) or chloride (4a) ligands. The novel compounds 2a-b, 3a-b and 4a were characterized by analytical and spectroscopic techniques, and the single crystal X-ray structure of one isomer of 4a was determined. In general, diiron complexes exhibited a moderate activity in combination with potassium hydroxide; [Fe 2 Cp 2 (CN)(CO)(μ-CO){μ-CN (Me)(4-C 6 H 4 OMe)}], 3a, emerged as the best catalyst, and the study of its activity was extended to a range of other ketones. DFT calculations suggest an unusual carbyne-centred mechanism, and the better performance displayed by 3a is ascribable to the stabilizing effect provided by the cyanide co-ligand, which is experimentally supported by IR analyses.

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Adding Diversity to a Diruthenium Biscyclopentadienyl Scaffold via Alkyne Incorporation: Synthesis and Biological Studies

et al. 2023

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We report the synthesis and the assessment of the anticancer potential of two series of diruthenium biscyclopentadienyl carbonyl complexes. Novel dimetallacyclopentenone compounds (2−4) were obtained (45−92% yields) from the thermal reaction (PhCCPh exchangeProtonation of 1−3 by HBF 4 afforded the corresponding μ-alkenyl derivatives 5−7, in 40−86% yields. All products were characterized by IR and NMR spectroscopy; moreover, cyclic voltammetry (1, 2, 5, 7) and single-crystal X-ray diffraction (5, 7) analyses were performed on representative compounds. Complexes 5−7 revealed a cytotoxic activity comparable to that of cisplatin in A549 (lung adenocarcinoma), SW480 (colon adenocarcinoma), and ovarian (A2780) cancer cell lines, and 2, 5, 6, and 7 overcame cisplatin resistance in A2780cis cells. Complexes 2, 5, and 7 (but not the aspirin derivative 6) induced an increase in intracellular ROS levels. Otherwise, 6 strongly stabilizes and elongates natural DNA (from calf thymus, CT-DNA), suggesting a possible intercalation binding mode, whereas 5 is less effective in binding CT-DNA, and 7 is ineffective. This trend is reversed concerning RNA, and in particular, 7 is able to bind poly(rA)poly(rU) showing selectivity for this nucleic acid. Complexes 5−7 can interact with the albumin protein with a thermodynamic signature dominated by hydrophobic interactions. Overall, we show that organometallic species based on the Ru 2 Cp 2 (CO) x scaffold (x = 2, 3) are active against cancer cells, with different incorporated fragments influencing the interactions with nucleic acids and the production of ROS.

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Alkylidyne and Alkylidene Complexes of Iron

Cited by 7 publications

References 218 publications

Construction of Two-Faced (Hetero)hydrocarbyl Diiron Complexes Mediated by the Interplay of Ligands

Construction of Two-Faced (Hetero)hydrocarbyl Diiron Complexes Mediated by the Interplay of Ligands

Diiron bis‐cyclopentadienyl complexes as transfer hydrogenation catalysts: The key role of the bridging aminocarbyne ligand

Adding Diversity to a Diruthenium Biscyclopentadienyl Scaffold via Alkyne Incorporation: Synthesis and Biological Studies

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