Formal chromium–chromium triple bonds and bent rings in the binuclear cycloheptatrienylchromium carbonyls (C7H7)2Cr2(CO)n (n=6,5,4,3,2,1,0): A density functional theory study

Wang, Hongyan; Xie, Yaoming; King, R. B.; Schaefer, Henry F.

doi:10.1016/j.jorganchem.2008.06.036

Cited by 6 publications

(5 citation statements)

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“…The [(h 7 -C 7 H 7 ) 2 Mo 2 (CO) n ] derivatives differ from their chromium analogues [(h 7 -C 7 H 7 ) 2 Cr 2 (CO) n ] in that heptahapto h 7 -C 7 H 7 Mo structures are low-energy structures for derivatives with four or less carbonyl groups. In contrast to the previous work [19] with the chromium compounds, no low-energy [(C 7 H 7 ) 2 Mo 2 (CO) n ] structures with rearranged C 7 H 7 rings were found.…”

Section: Discussioncontrasting

confidence: 99%

“…DFT studies similar to those discussed in the present paper were previously reported for the chromium analogues [(C 7 H 7 ) 2 Cr 2 (CO) x ] (x = 6, 5, 4, 3, 2, 1, 0) [19] as part of a systematic study of isoelectronic series of [(h n -C n H n ) 2 M 2 (CO) x ] derivatives of the first-row transition metals (x = 4, 3, 2, 1: n = 4, M = Co [20] ; n = 5, M = Fe [21] ; n = 6, M = Mn [22] ; n = 7, M = Cr [19] ). For the C 4 H 4 Co, C 5 H 5 Fe, and C 6 H 6 Mn derivatives, all of the optimized structures contained h n -C n H n rings, fully bonded to the metal through all n carbon atoms.…”

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confidence: 83%

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Heptahapticity in Binuclear (Cycloheptatrienyl)molybdenum Carbonyl Derivatives: The Interplay between Ring Hapticity/Planarity and Metal–Metal Multiple Bonding

Feng

Xie

et al. 2010

Chemistry An Asian Journal

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Theoretical studies on the binuclear (cycloheptatrienyl)molybdenum carbonyl complexes [(C(7)H(7))(2)Mo(2)(CO)(n)] (n=6, 5, 4, 3, 2, 1, 0) indicate structures with fully bonded heptahapto eta(7)-C(7)H(7) rings and four or fewer carbonyl groups to be energetically competitive. This is in striking contrast to the corresponding chromium derivatives. The lowest energy of such a structure for [(eta(7)-C(7)H(7))(2)Mo(2)(CO)(4)] is a singlet unbridged structure with a formal Mo--Mo single bond with a length of approximately 3.2 A. A higher-energy pentahapto structure [(eta(5)-C(7)H(7))(2)Mo(2)(CO)(4)] is also predicted with a formal Mo [triple bond]Mo triple bond with a length of approximately 2.56 A. Low-energy structures are predicted for [(C(7)H(7))(2)Mo(2)(CO)(3)] with two heptahapto eta(7)-C(7)H(7) rings, either one or two bridging carbonyl groups, and formal Mo=Mo double bonds with a length of approximately 2.8 A. However, the global minimum for [(C(7)H(7))(2)Mo(2)(CO)(3)] is a [(eta(7)-C(7)H(7))(eta(5)-C(7)H(7))Mo(2)(CO)(3)] structure with a formal Mo[triple bond]Mo triple bond with a length of approximately 2.53 A. The lowest-energy structures for [(C(7)H(7))(2)Mo(2)(CO)(2)] and [(C(7)H(7))(2)Mo(2)(CO)] have heptahapto eta(7)-C(7)H(7) rings and predicted metal-metal bond lengths of approximately 2.54 and 2.31 A, respectively, consistent with the formal triple and quadruple bonds, respectively, needed to give both metal atoms the favored 18-electron configuration. The lowest-energy structures for the carbonyl-richer systems [(C(7)H(7))(2)Mo(2)(CO)(n)] (n=6, 5) contain one trihapto eta(3)-C(7)H(7) ring and one pentahapto eta(5)-C(7)H(7) ring.

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confidence: 99%

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confidence: 83%

Heptahapticity in Binuclear (Cycloheptatrienyl)molybdenum Carbonyl Derivatives: The Interplay between Ring Hapticity/Planarity and Metal–Metal Multiple Bonding

Feng

Xie

et al. 2010

Chemistry An Asian Journal

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“…This relatively low bond order could be explained by MOs sketching in Figure 2, showing clearly the existence of one σ and two π Cr Cr occupied bonding d-type orbitals and their counterparts vacant antibonding ones, whereas the remaining d-type orbitals are strongly combined in-phase with those of carbonyls. The η 5 coordination mode of both Cp À and Ind À toward the Cr 2 2+ moiety instead of η 3 as obtained for related complexes [47] prevents a high Cr Cr bonding which favoring the metal X and metal L bonding giving rise to 24-MVE species isoelectronic to those reported in the literature [95,96].…”

Section: Resultssupporting

confidence: 54%

Terminal and bridging ligand effects on M(I)M(I) multiple bonding: ADFTinvestigation of the coordination in (X)[M₂Cl]L₂complexes (M = Cr,Fe,L = CO,PEt₃,X = Cl, allyl,Cp, and indenyl)

Mecheri

Zouchoune

2023

Int J of Quantum Chemistry

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A theoretical DFT investigation has been achieved on (X)[M2Cl]L2 (M = Cr, Fe, L = CO, PEt3, and X = allyl, cyclopentadienyl, and indenyl) complexes by means of BP86 and B3LYP* functionals. The geometry optimizations showed an η3‐coordination for the allyl, while Cp and indenyl ligands adopt the same η5‐coordination mode and the chloride acts as bridging ligand. The metal–metal bond distances are very sensitive to the replacement of the CO with PEt3 (triethylphosphine) with regard to the electron‐donation and electron π‐backdonation properties for the former and only to the electron‐donation for the later. This replacement impacts drastically the metal–metal bonding. Changing the metal from Cr to Fe increases the metal–metal bond distance, decreases the bond order and the oxidation sate of Fe, in agreement with the decrease of Wiberg bond indices (WBI) and Mayer bond order values (MBO). The findings showed that the Cl− and allyl− behave as 4‐electron donors, while Cp− and Ind− behave as 6–electron donors leading to outstanding electron properties stemming from different coordination, which are clarified by the σ‐donation and π‐backdonation properties, which are highlighted by the orbitals' populations and the energy decomposition analysis (EDA). Based on the aforementioned information, the chromium and iron complexes of Cl− and allyl− are of 22‐ and 24‐metal valence electrons (MVE), where those of Cp− and Ind− are of 26‐ and 28‐MVE, respectively. It is well noted that the metal–metal multiple bonding overcomes the electrons' deficiency.

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“…272 The ground state triplet tricarbonyl Cp 2 Cr 2 (CO) 3 has an R MM value of 2.295 Å interpreted as a CrCr triple bond, while the higher energy singlet has an R MM value of 2.191 Binuclear cycloheptatrienyl chromium carbonyl complexes of the series (C 7 H 7 ) 2 Cr 2 (CO) n (n = 1 to 6) have been studied by DFT methods (BP86 results in Table 14). 273 These structures have two cycloheptatrienyl ligands each bonded to one Cr center of the MM core. The cycloheptatrienyl rings display variable hapticity, with heptahapto coordination in lower energy structures seen only for n = 1.…”

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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Formal chromium–chromium triple bonds and bent rings in the binuclear cycloheptatrienylchromium carbonyls (C7H7)2Cr2(CO)n (n=6,5,4,3,2,1,0): A density functional theory study

Cited by 6 publications

References 49 publications

Heptahapticity in Binuclear (Cycloheptatrienyl)molybdenum Carbonyl Derivatives: The Interplay between Ring Hapticity/Planarity and Metal–Metal Multiple Bonding

Heptahapticity in Binuclear (Cycloheptatrienyl)molybdenum Carbonyl Derivatives: The Interplay between Ring Hapticity/Planarity and Metal–Metal Multiple Bonding

Terminal and bridging ligand effects on M(I)M(I) multiple bonding: ADFTinvestigation of the coordination in (X)[M₂Cl]L₂complexes (M = Cr,Fe,L = CO,PEt₃,X = Cl, allyl,Cp, and indenyl)

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

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Formal chromium–chromium triple bonds and bent rings in the binuclear cycloheptatrienylchromium carbonyls (C7H7)2Cr2(CO)n (n=6,5,4,3,2,1,0): A density functional theory study

Cited by 6 publications

References 49 publications

Heptahapticity in Binuclear (Cycloheptatrienyl)molybdenum Carbonyl Derivatives: The Interplay between Ring Hapticity/Planarity and Metal–Metal Multiple Bonding

Heptahapticity in Binuclear (Cycloheptatrienyl)molybdenum Carbonyl Derivatives: The Interplay between Ring Hapticity/Planarity and Metal–Metal Multiple Bonding

Terminal and bridging ligand effects on M(I)M(I) multiple bonding: ADFTinvestigation of the coordination in (X)[M2Cl]L2complexes (M = Cr,Fe,L = CO,PEt3,X = Cl, allyl,Cp, and indenyl)

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

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Terminal and bridging ligand effects on M(I)M(I) multiple bonding: ADFTinvestigation of the coordination in (X)[M₂Cl]L₂complexes (M = Cr,Fe,L = CO,PEt₃,X = Cl, allyl,Cp, and indenyl)