Synthesis and X-ray structure of tri-µ-carbonyl-bis-(1,2-diphenyl-3,4-di-t-butylcyclobutadiene)di-iron

Murahashi, Shun‐Ichi; Mizoguchi, Takahisa; Hosokawa, Takahiro; Moritani, Ichiro; Kohara, Masashi; Yasuoka, Noritake; Kasai, Nobutami

doi:10.1039/c39740000563

Cited by 28 publications

(7 citation statements)

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“…In this context it would appear that the present 2.343 Å distance in 9a is too long to be a true triple bond. Note, however, the experimental structure 51 is triply bridged, yielding an FetFe distance significantly shorter than would be expected from the singly bridged structure 9a.…”

Section: Reciprocal Diagonal Compliance Matrix Elementsmentioning

confidence: 82%

Remarkable Aspects of Unsaturation in Trinuclear Metal Carbonyl Clusters: The Triiron Species Fe₃(CO)_n (n = 12, 11, 10, 9)

et al. 2006

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The trinuclear iron carbonyls Fe(3)(CO)(n) (n = 12, 11, 10, 9) have been studied by density functional theory using the B3LYP and BP86 functionals. The experimentally known C(2)(v) isomer of Fe(3)(CO)(12), namely Fe(3)(CO)(10)(mu-CO)(2), is found to be the global minimum below the unbridged D(3)(h) isomer analogous to the known structures for Ru(3)(CO)(12) and Os(3)(CO)(12). The lowest-energy isomer found for Fe(3)(CO)(11) is Fe(3)(CO)(9)(mu(3)-CO)(2) with iron-iron distances in the Fe(3) triangle, suggesting the one double bond (2.460 A by B3LYP and 2.450 A by BP86) and two single bonds (2.623 A by B3LYP and 2.604 A by BP86) required to give each Fe atom the favored 18-electron configuration. Two different higher-energy dibridged structures Fe(3)(CO)(9)(mu(2)-CO)(2) are also found for Fe(3)(CO)(11). The lowest-energy isomer found for Fe(3)(CO)(10) is Fe(3)(CO)(9)(mu(3)-CO) with equivalent iron-iron distances in the Fe(3) ring (2.47 A by B3LYP or BP86). The lowest-energy isomer found for Fe(3)(CO)(9) is Fe(3)(CO)(6)(mu-CO)(3) with distances in the Fe(3) triangle possibly suggesting one single bond (2.618 A by B3LYP and 2.601 A by BP86), one weak double bond (2.491 A by B3LYP and 2.473 A by BP86), and one weak triple bond (2.368 A by B3LYP and 2.343 A by BP86). A higher-lying isomer of Fe(3)(CO)(9), i.e., Fe(3)(CO)(8)(mu-CO), at approximately 21 kcal/mol above the global minimum, has iron-iron distances strongly suggesting two single bonds (2.6 to 2.7 A) and one quadruple bond (2.068 A by B3LYP and 2.103 A by BP86). Wiberg Bond Indices are also helpful in evaluating the iron-iron bond orders.

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Section: Reciprocal Diagonal Compliance Matrix Elementsmentioning

confidence: 82%

Remarkable Aspects of Unsaturation in Trinuclear Metal Carbonyl Clusters: The Triiron Species Fe₃(CO)_n (n = 12, 11, 10, 9)

et al. 2006

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“…triple bond. 6 The gross electronic structure of such complexes has been described briefly by us,4 and we elaborate on that here.…”

Section: Complexes Bridged By Acceptorsmentioning

confidence: 90%

M2L9 complexes

Summerville¹,

Hoffmann²

1979

J. Am. Chem. Soc.

144

101

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“…The prospect for synthesizing binuclear iron carbonyl derivatives containing iron−iron multiple bonds can be improved if some of the carbonyl groups are replaced by other ligands, thereby suppressing elimination of Fe(CO) 5 by eq 9 leading to rupture of the iron−iron bond. Of particular interest are some reported and structurally characterized binuclear cyclobutadiene iron carbonyl complexes of the type (η 4 -R 4 C 4 )Fe(μ-CO) 3 Fe(η 4 -C 4 R 4 ) ( 3 : R = H and C 6 H 5 ). The structure of the phenyl derivative has been found by X-ray diffraction to be very similar to our tribridged structure of C 2 v -Fe 2 (CO) 7 (Figure ), but with the pair of terminal carbonyl groups on each iron atom replaced by a single tetraphenylcyclobutadiene ligand.…”

Section: Synthetic Prospectsmentioning

confidence: 99%

Binuclear Homoleptic Iron Carbonyls: Incorporation of Formal Iron−Iron Single, Double, Triple, and Quadruple Bonds, Fe₂(CO)_x (x = 9, 8, 7, 6)

2000

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The homoleptic binuclear compound Fe 2 (CO) 9 is well characterized experimentally, although there has been some discussion as to the nature of the iron-iron bond, which is at most a single bond. In this research, we consider homoleptic iron carbonyls that satisfy the 18-electron rule but may have formal double Fe 2 (CO) 8 (seven distinct structures), triple Fe 2 (CO) 7 (three distinct structures), and even quadruple Fe 2 (CO) 6 (seven distinct structures) iron-iron bonds. These novel structures are characterized in terms of their equilibrium geometries, thermochemistry, and vibrational frequencies. The range of predicted iron-iron distances is remarkable, from 2.52 Å for the known Fe 2 (CO) 9 to 2.00 Å for the unbridged quadruple bond species Fe 2 -(CO) 6 . The lowest energy structure of Fe 2 (CO) 7 is a distorted unbridged C s symmetry structure with ironiron separation 2.23 Å. This is followed energetically by the tribridged structure with bond distance 2.21 Å, and finally by the monobridged structure with iron-iron distance 2.13 Å. The latter structure is consistent with an FetFe triple bond, but is not a genuine minimum. For Fe 2 (CO) 6 the lowest energy structure is the distorted dibridged structure with perhaps a weak FedFe double bond. However, the unbridged Fe 2 (CO) 6 structure with an iron-iron bond distance of 2.00 Å (suggesting a quadruple bond) is also a genuine minimum. The unsaturated structures Fe 2 (CO) 8 and Fe 2 (CO) 7 , are thermodynamically resistant to CO removal. The ironiron linkages are also analyzed in terms of contributions from the different vibrational potential energy distributions. A clear Badger's Rule correlation between Fe-Fe vibrational frequency and bond distance is established. Prospects for the synthesis of these and related diiron compounds are discussed in some detail. The most promising routes to preparation of these fascinating species would appear to be matrix isolation or iron vapor synthesis.

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Synthesis and X-ray structure of tri-µ-carbonyl-bis-(1,2-diphenyl-3,4-di-t-butylcyclobutadiene)di-iron

Cited by 28 publications

References 0 publications

Remarkable Aspects of Unsaturation in Trinuclear Metal Carbonyl Clusters: The Triiron Species Fe₃(CO)_n (n = 12, 11, 10, 9)

Remarkable Aspects of Unsaturation in Trinuclear Metal Carbonyl Clusters: The Triiron Species Fe₃(CO)_n (n = 12, 11, 10, 9)

M2L9 complexes

Binuclear Homoleptic Iron Carbonyls: Incorporation of Formal Iron−Iron Single, Double, Triple, and Quadruple Bonds, Fe₂(CO)_x (x = 9, 8, 7, 6)

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Synthesis and X-ray structure of tri-µ-carbonyl-bis-(1,2-diphenyl-3,4-di-t-butylcyclobutadiene)di-iron

Cited by 28 publications

References 0 publications

Remarkable Aspects of Unsaturation in Trinuclear Metal Carbonyl Clusters: The Triiron Species Fe3(CO)n (n = 12, 11, 10, 9)

Remarkable Aspects of Unsaturation in Trinuclear Metal Carbonyl Clusters: The Triiron Species Fe3(CO)n (n = 12, 11, 10, 9)

M2L9 complexes

Binuclear Homoleptic Iron Carbonyls: Incorporation of Formal Iron−Iron Single, Double, Triple, and Quadruple Bonds, Fe2(CO)x (x = 9, 8, 7, 6)

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Remarkable Aspects of Unsaturation in Trinuclear Metal Carbonyl Clusters: The Triiron Species Fe₃(CO)_n (n = 12, 11, 10, 9)

Remarkable Aspects of Unsaturation in Trinuclear Metal Carbonyl Clusters: The Triiron Species Fe₃(CO)_n (n = 12, 11, 10, 9)

Binuclear Homoleptic Iron Carbonyls: Incorporation of Formal Iron−Iron Single, Double, Triple, and Quadruple Bonds, Fe₂(CO)_x (x = 9, 8, 7, 6)