Iminium substituent directs cyanide and hydride additions to triiron vinyliminium complexes

Schoch, Silvia; Bresciani, Giulio; Saviozzi, Chiara; Funaioli, Tiziana; Bortoluzzi, Marco; Pampaloni, Guido; Marchetti, Francesca

doi:10.1039/d2nj05810c

Cited by 2 publications

(1 citation statement)

References 72 publications

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“…Expanding our understanding of the reactivity of 1-3 with cyanide is motivated by two primary reasons. First, the unsaturation within the bridging hydrocarbyl ligand offers opportunities to increase the complexity of the organic moiety [37][38][39], with the cyano group potentially acting as a nitrogen donor towards one of the two iron centers [40][41][42]. Second, the possibility of placing cyanide to occupy an iron coordination site deserves consideration for potential implications in catalysis [43].…”

Section: Introductionmentioning

confidence: 99%

Cyanide Addition to Diiron and Diruthenium Bis-Cyclopentadienyl Complexes with Bridging Hydrocarbyl Ligands

Cinci,

Ciancaleoni,

Zacchini

et al. 2024

Inorganics

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We conducted a joint synthetic, spectroscopic and computational study to explore the reactivity towards cyanide (from Bu4NCN) of a series of dinuclear complexes based on the M2Cp2(CO)3 scaffold (M = Fe, Ru; Cp = η5-C5H5), namely [M2Cp2(CO)2(µ-CO){µ,η1:η2-CH=C=CMe2}]BF4 (1Fe-Ru), [Ru2Cp2(CO)2(µ-CO){µ,η1:η2-C(Ph)=CHPh}]BF4 (2Ru) and [M2Cp2(CO)2(µ-CO){µ-CN(Me)(R)}]CF3SO3 (3Fe-Ru). While the reaction of 1Fe with Bu4NCN resulted in prevalent allenyl deprotonation, preliminary CO-NCMe substitution in 1Ru enabled cyanide addition to both the allenyl ligand (resulting in the formation of a h1:h2-allene derivative, 5A) and the two metal centers (affording 5B1 and 5B2). The mixture of 5B1-2 was rapidly converted into 5A in heptane solution at 100 °C, with 5A being isolated with a total yield of 60%. Following carbonyl-chloride substitution in 2Ru, CN− was incorporated as a terminal ligand upon Cl− displacement, to give the alkenyl complex 6 (84%). The reactivity of 3Fe and 3Ru is strongly influenced by both the metal element, M, and the aminocarbyne substituent, R. Thus, 7aRu was obtained with a 74% yield from cyanide attack on the carbyne in 3aRu (R = Cy, cyclohexyl), whereas the reaction involving the diiron counterpart 3aFe yielded an unclean mixture of the metastable 7aFe and the CO/CN− substitution product 8aFe. The cyano-alkylidene complexes 7aRu (R = Cy) and 7bFe (R = Me) underwent CO loss and carbene to carbyne conversion in isopropanol at 60–80 °C, giving 8aRu (48%) and 8bFe (71%), respectively. The novel compounds 5A, 5B1-2, 6 and 7aRu were characterized by IR and NMR spectroscopy, with the structure of 7aRu further elucidated by single crystal X-ray diffraction analysis. Additionally, the DFT-optimized structures of potential isomers of 5A, 5B1-2 and 6 were calculated.

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Section: Introductionmentioning

confidence: 99%

Cyanide Addition to Diiron and Diruthenium Bis-Cyclopentadienyl Complexes with Bridging Hydrocarbyl Ligands

Cinci,

Ciancaleoni,

Zacchini

et al. 2024

Inorganics

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Multisite Amino‐Allylidene Ligands from Thermal CO Elimination in Diiron Complexes and Catalytic Activity in Hydroboration Reactions

Zappelli,

Taglieri,

Schoch

et al. 2024

ChemCatChem

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The new diiron(I) complexes [Fe2Cp2(μ‐CO){μ‐k3C,kN‐C(R1)C(R2)C(CN)NMe(R)}], 3a‐o (R = alkyl or 4‐C6H4OMe; R1 = alkyl, aryl, ferrocenyl (Fc), thiophenyl, CO2Me or SiMe3; R2 = H, Me or CO2Me) were synthesized in moderate to high yields from the thermal decarbonylation of the bis‐carbonyl precursors 2a‐o, and were structurally characterized by IR and NMR spectroscopy, and single crystal X‐ray diffraction in four cases. Electrochemical behavior of one complex was also investigated. Complexes 3a‐o comprise a highly functionalized, multisite amino‐(cyano)allylidene ligand, including metal coordination of a tertiary amine group. Selected complexes displayed negligible to moderate catalytic activity in CO2/propylene oxide coupling, working under ambient conditions. Additionally, they were investigated as catalysts for the conversion of benzaldehyde to the corresponding borate ester 6a, using pinacolborane (HBpin) as the borylating agent. Most complexes achieved good conversions at room temperature with 1% catalyst loading, and data highlight the significant influence of the multisite ligand substituents on the catalytic performance. Notably, complex 3m (featuring R = 4‐methoxyphenyl, R1 = Fc, R2 = H) displayed the highest activity and effectively catalyzed the hydroboration of various aldehydes and ketones. A plausible mechanistic cycle involves metal coordination of the carbonyl substrate, its activation being possibly facilitated by intramolecular interactions.

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Iminium substituent directs cyanide and hydride additions to triiron vinyliminium complexes

Abstract: The reactivity of diiron bis-cyclopentadienyl cationic complexes containing a vinyliminium ligand coordinated to a diiron scaffold and decorated with a ferrocenyl group, [1a-g]CF3SO3, was investigated towards NBu4CN (in CH2Cl2) and...

Cited by 2 publications

References 72 publications

Cyanide Addition to Diiron and Diruthenium Bis-Cyclopentadienyl Complexes with Bridging Hydrocarbyl Ligands

Cyanide Addition to Diiron and Diruthenium Bis-Cyclopentadienyl Complexes with Bridging Hydrocarbyl Ligands

Multisite Amino‐Allylidene Ligands from Thermal CO Elimination in Diiron Complexes and Catalytic Activity in Hydroboration Reactions

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