Preparation and interconversion of binuclear 2-ferrazetine and isomeric ferrapyrrolinone complexes

Mirkin, Chad A.; Lu, Kuang Lieh; Snead, Thomas E.; Young, Bruce A.; Geoffroy, Gregory L.; Rheingold, Arnold L.; Haggerty, Brian S.

doi:10.1021/ja00010a024

Cited by 18 publications

(7 citation statements)

References 3 publications

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“…In 4 , the CO substrate has coupled to the erstwhile α-carbon of 1 , consistent with the mechanism proposed for the formation of ketenimine 2 in the presence of the isocyanide substrate (Scheme ). Similar metal–C insertion reactivity has been observed in reactions of CO with related bimetallic iron systems …”

Section: Resultssupporting

confidence: 71%

“…Similar metal−C insertion reactivity has been observed in reactions of CO with related bimetallic iron systems. 49 The iron center in complex 4 adopts an unusual fourcoordinate, trigonal-pyramidal geometry, 50 with the carbon ligand occupying the apical site and nitrogen atoms creating a trigonal plane (sum of the N−Fe−N bond angles = 359.17°). Overall, observations from the molecular structure of 4 suggest that this complex is most appropriately illustrated as shown on the right side of eq 1.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Carbene-Like Reactivity in an Iron Azametallacyclobutene Complex: Insights from Electronic Structure

2022

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Herein we describe our investigation into the electronic structure of the first isolated monometallic iron azametallacyclobutene complex. Computational analysis through density functional theory calculations reveals electron delocalization throughout the four atoms of the ring system, in line with experimental observations and supporting the classification of this complex as a conjugated metallacycle. The results of this study also point to significant contribution from an imine-substituted iron carbene resonance structure to the overall bonding picture for the azametallacyclobutene. Accordingly, this complex participates in carbene-like reactivity in the presence of an isocyanide substrate to generate a ketenimine product. The related reaction with carbon monoxide leads to the isolation of a five-membered metallacycle that is analogous to the proposed intermediate in ketenimine formation, and confirms the α-carbon as the site of reactivity.

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Section: Resultssupporting

confidence: 71%

Section: ■ Results and Discussionmentioning

confidence: 99%

Carbene-Like Reactivity in an Iron Azametallacyclobutene Complex: Insights from Electronic Structure

2022

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“…According to the crystal structure of 2b , which is representative for all products 1b − 5b , this ν(CO) band belongs to a CO ligand forming an Os−C(O)−N−Os bridge. To our knowledge such a bridge has never been observed for any other triosmium cluster, although it has been reported for the dinuclear compounds Ru 2 (CO) 6 (azadiene) and Ru 2 (CO) 6 (azaallyl) and for isostructural diiron derivatives of the latter complex . These binuclear complexes exhibit a similar low-frequency IR band (1682−1727 cm -1 ) due to the bridging carbonyl ligand.…”

Section: Discussionmentioning

confidence: 61%

Light-Induced Insertion of a CO Ligand into an Os−N Bond of the Clusters Os₃(CO)₁₀(L), Where L Represents a Potentially Terdentate N,N‘-Chelating α-Diimine

et al. 1999

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Irradiation of the clusters Os3(CO)10(L) (L = pyridine-2-carbaldehyde-N‘-R imine (R−PyCa), R = Me2N(CH2)2 (1), Me2N(CH2)3 (5), (2-pyridyl)(CH2)2 (3); L = 2-acetylpyridine-N ‘-R imine (R−AcPy), R = Me2N(CH2)2 (2), (2-pyridyl)(CH2)2 (4)) with visible light leads to the formation of the novel CO-bridged (Os 1 C(O)N‘Os 3 ; N‘ = imine nitrogen) photoproducts Os3(CO)9(μ -1κ C (CO) :1κ C (imine) :3κ 3 N,N ‘ ,N ‘ ‘ (R)-L-N ‘-C(O)) (2 Os − Os), 1b−5b, demonstrating the profound influence of the pendant Lewis base on the course of the photoreactions. Formation of the products 1b−5b occurs via the initial formation of a zwitterion. The efficiency of this step determines the quantum yield of the photoreaction. In strongly coordinating solvents (e.g., S = pyridine, acetonitrile) this is the solvent-stabilized zwitterion (CO)4Os-Os(CO)4Os+(CO)2(S)(κ 2 N,N ‘-L), whereas in noncoordinating solvents and in THF at ambient temperatures this is the intramolecularly stabilized zwitterion (CO)4Os-Os(CO)4Os+(CO)2(κ 3 N,N ‘ ,N ‘ ‘ (R)-L). The latter species is formed from the corresponding biradical (the primary photoproduct in these solvents) via attack of the pendant Lewis base on the {Os+(CO)2(κ 2 N,N ‘-L•-)} moiety, inducing an electron-transfer reaction. The biradical also undergoes a radical coupling side reaction, affording an unstable η 2 -imine-bridged product with the coordinatively unsaturated Os(CO)2(L) moiety, similar to an intermediate previously observed in the photoisomerization of Os3(CO)10(R−PyCa) (R = alkyl). This path does not contribute significantly to the net product formation. The novel compounds 1b−5b have been characterized by IR and (with the exception of thermally unstable 4b) NMR spectroscopy. The structure of 2b has been determined by an X-ray diffraction study.

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“…A search of the CSD 10 indicates no examples of previous X-ray structure determinations of benzoazaferrole systems. However, in two analogous ferrole complexes and a dibenzoferrole, Fe−C(σ) bond lengths are in the range 1.921−2.039 Å, mean 1.948(19) Å, Fe−C(π) lengths are in the range 2.035−2.216 Å, mean 2.125(15) Å, and Fe−Fe 2.466(1), 2.567(1), and 2.468(1) Å, similar to the lengths in 7 , and in the 3-ferra-4-pyrrolin-2-one complex Fe 2 (μ-CHCHNPhC{O})(CO) 6 , Fe−Fe is 2.597 Å …”

Section: Discussionmentioning

confidence: 63%

Reaction of Fe₃(CO)₁₂ with TelluriumNitrogen Heterocycles: A Source of Novel Organoiron Compounds

et al. 1997

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Heterocyclic tellurium compounds containing both tellurium and nitrogen in the heterocyclic ring are shown to be useful precursors for the synthesis of novel organoiron compounds. Thus, reaction of Fe3(CO)12 with benzoisotellurazole yields (C6H4CHNTe)2Fe3(CO)7, 5. The structure of 5 was established by X-ray crystallography; it is based on a nonlinear chain of three iron atoms, Fe1−Fe2−Fe3 133.4(1)°, with Fe1−Fe2, 2.472(2) Å doubly-bridged by nitrogen and Fe2−Fe3, 2.683(2) Å, doubly-bridged by tellurium. The reaction of Fe3(CO)12 with 2-methylbenzotellurazole results in two new crystalline products C18H7NFe3O10, 6, and C14H7NFe2O6, 7, involving detelluration of the heterocycle. X-ray crystallography shows that 6 contains a triangular arrangement of iron atoms, two edges of which are bridged respectively by the nitrogen and carbon atoms of the NC formal double bond and the latter edge is also bridged by a carbonyl in an almost symmetrical manner. The third edge of the iron triangle is not directly bridged, and at 2.647(1) Å, it is the longest edge of the triangle. In 7, one iron atom forms part of a benzoferrazole system, and the second iron is π-bonded to the CCNC residue of the ferrazole with a relatively short Fe−Fe contact of 2.498(1) Å.

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Preparation and interconversion of binuclear 2-ferrazetine and isomeric ferrapyrrolinone complexes

Cited by 18 publications

References 3 publications

Carbene-Like Reactivity in an Iron Azametallacyclobutene Complex: Insights from Electronic Structure

Carbene-Like Reactivity in an Iron Azametallacyclobutene Complex: Insights from Electronic Structure

Light-Induced Insertion of a CO Ligand into an Os−N Bond of the Clusters Os₃(CO)₁₀(L), Where L Represents a Potentially Terdentate N,N‘-Chelating α-Diimine

Reaction of Fe₃(CO)₁₂ with TelluriumNitrogen Heterocycles: A Source of Novel Organoiron Compounds

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Preparation and interconversion of binuclear 2-ferrazetine and isomeric ferrapyrrolinone complexes

Cited by 18 publications

References 3 publications

Carbene-Like Reactivity in an Iron Azametallacyclobutene Complex: Insights from Electronic Structure

Carbene-Like Reactivity in an Iron Azametallacyclobutene Complex: Insights from Electronic Structure

Light-Induced Insertion of a CO Ligand into an Os−N Bond of the Clusters Os3(CO)10(L), Where L Represents a Potentially Terdentate N,N‘-Chelating α-Diimine

Reaction of Fe3(CO)12 with TelluriumNitrogen Heterocycles: A Source of Novel Organoiron Compounds

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Product

Resources

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Light-Induced Insertion of a CO Ligand into an Os−N Bond of the Clusters Os₃(CO)₁₀(L), Where L Represents a Potentially Terdentate N,N‘-Chelating α-Diimine

Reaction of Fe₃(CO)₁₂ with TelluriumNitrogen Heterocycles: A Source of Novel Organoiron Compounds