[PPN]2[Cr2(CO)10], a Salt of the Dimeric Cr1− Carbonyl Complex Without a Coordinating Counterion

Lee, Inkyung; Geib, Steven J.; Cooper, N. John

doi:10.1107/s0108270195001454

Cited by 7 publications

(11 citation statements)

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“…The prediction for the bridged species is similar to that for the solid crystal owing to the Cr-H interaction and the stabilizing nature of the bridging species. This is in contrast to the [Cr 2 (CO) 10 ] 2À dianion which is predicted to have a somewhat longer Cr-Cr distance, (3.30 A ˚, both functionals) than the experimental distances (2.98-3.00 A ˚) for Cr-Cr in [Cr 2 (CO) 10 ] 2À crystals 26,27 The difference between the isolated gas phase species, in which some bond lengthening is possible, and the constrained environment of the solid crystal may account for this difference in the dianion geometry. With only the dianion differing significantly from experimentally determined geometry (explainable by the effects of excess charge) these results would seem to indicate at least a qualitative reliability of DFT for these molecules.…”

Section: The Reliability Of Dft For Chromium Carbonylscontrasting

confidence: 57%

“…Substitution of the bridging CO in Cr 2 (CO) 11 with a hydride produces the stable and well-known HCr 2 (CO) 10 À , for which we also predicted the gas phase structure and compared it to two X-ray structures. 10,11 Deprotonation of HCr 2 (CO) 10 À results in the known Cr 2 (CO) 10 2À , which has also been structurally characterized. 12 Electrochemical experiments have examined the one-electron oxidation of Cr 2 (CO) 10 2À to form Cr 2 (CO) 10 À and the process of Cr-Cr bond cleavage.…”

Section: Introductionmentioning

confidence: 99%

“…Transient (lifetime $10 À3 s) Cr 2 (CO) 10 has been observed in photochemical studies in which Cr(CO) 4 reacts with Cr(CO) 6 . 14 These experimental results indicate that Cr 2 (CO) 10 may have greater stability than the unsaturated Cr 2 (CO) 11 , and thus theoretical investigation of Cr 2 (CO) 10 has been undertaken to determine the nature of this molecule and reasons for its stability.…”

Section: Introductionmentioning

confidence: 99%

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The rule breaking Cr₂(CO)₁₀. A 17 electron Cr system or a CrCr double bond?

Richardson

Xie

et al. 2003

Faraday Discuss.

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Density functional theory (DFT) has been used to investigate the conformations and thermochemistry on the singlet and triplet potential energy surfaces (PES) of Cr2(CO)10. The global minimum energy structure for the lowest singlet state of C2h symmetry is consistent with a model of two interacting Cr(CO)5 fragments in which one carbonyl in each fragment acts as an asymmetric four-electron donor bridging carbonyl, with chromium-chromium distances of 2.93 A (B3LYP) or 2.83 A (BP86). Avoiding a Cr...Cr bond by incorporating four-electron donor CO groups in this way allows each chromium atom in singlet Cr(CO)10 to attain the favored 18-electron configuration by using, in a simple picture of the bonding, only the six octahedral sp3d2 hybrids. The dissociation energy to two Cr(CO)5 fragments or to Cr(CO)6 + Cr(CO)4 fragments is predicted to be 10 kcal mol(-1). The lowest triplet state of Cr2(CO)10 is predicted to lie approximately 10 kcal mol(-1) above the singlet global minimum. In the case of triplet Cr2(CO)10 the lowest energy minima were found to be of C2 and C2h symmetry, with similar energies. The chromium-chromium distances in triplet Cr2(CO)10 were found to be shorter than those in the corresponding singlet structures, namely 2.81 (B3LYP) or 2.68 A (BP86) suggesting a sigma + 2(1/2) pi Cr=Cr double bond similar to the O=O bond in O2 or the Fe=Fe bond in the experimentally observed triplet state (Me5C5)2Fe2(mu-CO)3.

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Section: The Reliability Of Dft For Chromium Carbonylscontrasting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The rule breaking Cr₂(CO)₁₀. A 17 electron Cr system or a CrCr double bond?

Richardson

Xie

et al. 2003

Faraday Discuss.

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“…258 The BP86 results on Cr 2 (CO) 10 (02) gave a singlet global minimum with two η 2 -μ-CO groups, 258,261 interpreted as a hybrid between a structure with a CrCr double bond and one having a weak Cr•••Cr interaction, leading to a Cr−Cr distance of 2.832 Å. Triplet Cr 2 (CO) 10 lies ∼10 kcal/mol higher in energy with a CrCr distance of 2.726 Å corresponding to a weak double bond of the σ + 2/2 π type. The [Cr 2 (CO) 10 ] 2− dianion 03 was shown experimentally to be an unbridged structure with a Cr−Cr bond length of 2.98 to 3.00 Å (Hey-Hawkins, 262 Lee, Geib, and Cooper, 263 and Schrobilgen 264 ). This Cr−Cr bond length is shorter than that predicted for Cr 2 (CO) 11 .…”

Section: Binuclear Chromium Carbonyl Complexesmentioning

confidence: 99%

Metal–Metal (MM) Bond Distances and Bond Orders in Binuclear Metal Complexes of the First Row Transition Metals Titanium Through Zinc

2018

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This survey of metal–metal (MM) bond distances in binuclear complexes of the first row 3d-block elements reviews experimental and computational research on a wide range of such systems. The metals surveyed are titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc, representing the only comprehensive presentation of such results to date. Factors impacting MM bond lengths that are discussed here include (a) the formal MM bond order, (b) size of the metal ion present in the bimetallic core (M2) n+, (c) the metal oxidation state, (d) effects of ligand basicity, coordination mode and number, and (e) steric effects of bulky ligands. Correlations between experimental and computational findings are examined wherever possible, often yielding good agreement for MM bond lengths. The formal bond order provides a key basis for assessing experimental and computationally derived MM bond lengths. The effects of change in the metal upon MM bond length ranges in binuclear complexes suggest trends for single, double, triple, and quadruple MM bonds which are related to the available information on metal atomic radii. It emerges that while specific factors for a limited range of complexes are found to have their expected impact in many cases, the assessment of the net effect of these factors is challenging. The combination of experimental and computational results leads us to propose for the first time the ranges and “best” estimates for MM bond distances of all types (Ti–Ti through Zn–Zn, single through quintuple).

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“…Preparation of Na 2 [Cr(CO) 5 ] has been achieved by the reduction of [Cr(CO) 5 NMe 3 ] using alkali metal (Li + or Na + ) naphthalenide in dry THF (Maher et al, 1985(Maher et al, , 1986). An increased stirring time for this reaction (>12 h) and metathesis with (PPN)Cl (PPN is Ph 3 P N PPh 3 + ) produces (PPN) 2 [Cr 2 (CO) 10 ] (Lee et al, 1996). Related compounds containing a six-coordinated Cr atom have also been reported, for example, (PPh 4 )[HCr-(CO) 5 ] (Darensbourg et al, 1982) and [(NHMe 2 )Cr(CO) 5 ] (Rogers & Alt, 1992).…”

Section: Commentmentioning

confidence: 99%

The pentacoordinated [Cr(CO)₅]²⁻dianion in [2,2,2-crypt-K]₂[Cr(CO)₅] ethylenediamine monosolvate

Zhai

2011

Acta Crystallogr C

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Bis[(4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane)potassium(+)] pentacarbonylchromate(2-) ethylenediamine monosolvate, [K(C(18)H(36)N(2)O(6))](2)[Cr(CO)(5)]·C(2)H(8)N(2), was obtained from the reaction between K(3)Cd(2)Sb(2) and Cr(CO)(6) in ethylenediamine in the presence of the macrocyclic 2,2,2-crypt ligand. The structure provides the first crystallographic characterization of the pentacoordinated [Cr(CO)(5)](2-) dianion. The central Cr(III) atom is coordinated by five carbonyl ligands in a distorted trigonal-bipyramidal geometry. The distribution of the Cr-C bond lengths indicates a greater degree of back bonding from Cr(III) to the equatorial carbonyl ligands compared with the axial carbonyl ligands.

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[PPN]2[Cr2(CO)10], a Salt of the Dimeric Cr1− Carbonyl Complex Without a Coordinating Counterion

Cited by 7 publications

References 2 publications

The rule breaking Cr₂(CO)₁₀. A 17 electron Cr system or a CrCr double bond?

The rule breaking Cr₂(CO)₁₀. A 17 electron Cr system or a CrCr double bond?

Metal–Metal (MM) Bond Distances and Bond Orders in Binuclear Metal Complexes of the First Row Transition Metals Titanium Through Zinc

The pentacoordinated [Cr(CO)₅]²⁻dianion in [2,2,2-crypt-K]₂[Cr(CO)₅] ethylenediamine monosolvate

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[PPN]2[Cr2(CO)10], a Salt of the Dimeric Cr1− Carbonyl Complex Without a Coordinating Counterion

Cited by 7 publications

References 2 publications

The rule breaking Cr2(CO)10. A 17 electron Cr system or a CrCr double bond?

The rule breaking Cr2(CO)10. A 17 electron Cr system or a CrCr double bond?

Metal–Metal (MM) Bond Distances and Bond Orders in Binuclear Metal Complexes of the First Row Transition Metals Titanium Through Zinc

The pentacoordinated [Cr(CO)5]2−dianion in [2,2,2-crypt-K]2[Cr(CO)5] ethylenediamine monosolvate

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Product

Resources

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The rule breaking Cr₂(CO)₁₀. A 17 electron Cr system or a CrCr double bond?

The rule breaking Cr₂(CO)₁₀. A 17 electron Cr system or a CrCr double bond?

The pentacoordinated [Cr(CO)₅]²⁻dianion in [2,2,2-crypt-K]₂[Cr(CO)₅] ethylenediamine monosolvate