The synthesis and characterisation of homo- and heterobimetallic 1,14,2,9- and 1,14,2,10-M2C2B1014-vertex metallacarboranes

McAnaw, Amelia; López, Marı́a Elena; Ellis, David; Rosair, Georgina M.; Welch, Alan J.

doi:10.1039/c2dt31598j

Cited by 16 publications

(18 citation statements)

References 29 publications

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“…[15] Key ELO data for these, together with those of the closely related species [3-μ-(PPh 2 CH 2 PPh 2 )-{3,3-(CO) 2 -3,1,2-closo-RuC 2 B 9 H 11 } 2 ] (HIZQUC), [16] are presented in Tables 1 and 2. 1.889 (6) Initially, the published cage C atom positions in each database structure were checked by the vertex-to-centroid distance (VCD) method, [4] and they were found to be correct in all three cases. Then, for each ligand, the parameter θ, which defines the ligand orientation, was calculated as described in Figure 1.…”

Section: Resultsmentioning

confidence: 99%

“…Compound 2 crystallises with one molecule of DCM per metallacarborane, 4 with two molecules of CHCl 3 per metallacarborane, and 5 with one molecule of CHCl 3 per metallacarborane, the last partially disordered. Cage C atoms bearing only H substituents were distinguished from B atoms by the VCD [4] and BHD [33] methods. H atoms bound to cage B or cage C atoms were allowed to refine positionally whilst H atoms bound to other C atoms were constrained to idealised geometries; C phenyl -H = 0.95 Å, C primary -H = 0.98 Å, C secondary -H = 0.99 Å, C tertiary -H = 1.00 Å.…”

Section: Crystallographic Studiesmentioning

confidence: 99%

“…We have previously named this phenomenon exopolyhedral ligand orientation (ELO). [4] Amongst many examples of ELO are the preferred cisoid conformations in indenyl and naphthalene metallacarboranes [5] and the motivation to rede-compound 4 has effective C s symmetry with one CO ligand trans and the other CO ligand cis to the cage C-C connectivity. Unexpectedly the Mo-CO bond lengths are equal.…”

Section: Introductionmentioning

confidence: 99%

“…termine the structure of [3,3-(κ 2 -NO 2 )-3-PPh 3 -3,1,2-closo-RhC 2 B 9 H 11 ]. [4] The origin of a preferred ELO is electronic, and hence the interpretation of a molecular structure in terms of ELO assumes no significant competing steric effects. For this reason ELO analysis is best done by using carborane ligands with only H substituents, for example [L x MC 2 B 9 H 11 ] species.…”

Section: Introductionmentioning

confidence: 99%

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Balancing Steric and Electronic Effects in Carbonyl–Phosphine Molybdacarboranes

et al. 2017

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Analysis of the literature structures [(CO)(PPh3)2MC2B9H11] and [(CO)2(PPh3)MC2B9H11] suggests that in [L3MC2B9H11] metallacarboranes the trans influence of CO is greater than that of PPh3. Extending this study to the [L4MC2B9H11] system the new molybdacarboranes [3,3,3‐(CO)3‐3‐PPh3‐3,1,2‐closo‐MoC2B9H11] (2), [1,2‐Me2‐3,3,3‐(CO)3‐3‐PPh3‐3,1,2‐closo‐MoC2B9H9] (3) and trans‐[3,3‐(CO)2‐3,3‐(PPh3)2‐3,1,2‐closo‐MoC2B9H11] (4) were prepared and fully characterised. Consideration of the exopolyhedral ligand orientations (ELO) in 2 confirms that, in terms of trans influence, CO > PPh3 in [L4MC2B9H11] also. The ELO is effectively reversed in 3 through intramolecular steric crowding between the cage CH3 groups and the PPh3 ligand. The dicarbonylbis(triphenylphosphine) compound 4 has effective Cs symmetry with one CO ligand trans and the other CO ligand cis to the cage C–C connectivity. Unexpectedly the Mo–CO bond lengths are equal. DFT calculations on 4 reproduce this unusual result, but suggest that in the less‐crowded PH3 analogue, the Mo–CO bond length trans to cage C would be about 0.2 Å shorter than that trans to cage B. To test this prediction, the analogous PEt3 complex was prepared as cis and trans structural isomers 5 and 6. The cis isomer 5 is quantitatively converted into the trans isomer 6 when heated to reflux in THF. In 6 the Mo–CO bond more trans to cage C is about 0.2 Å shorter than that which is more trans to cage B, in line with the DFT prediction.

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Section: Resultsmentioning

confidence: 99%

Section: Crystallographic Studiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Balancing Steric and Electronic Effects in Carbonyl–Phosphine Molybdacarboranes

et al. 2017

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“…Initially, only the linking atoms C1 and C1 0 were identified as carbon, with all other C or B cage atoms described as boron and with cage H atoms allowed positional refinement. This model (the Prostructure) was refined and then analysed by both the vertex-to-centroid distance (VCD) (McAnaw et al, 2013) and the boron-hydrogen distance (BHD) (McAnaw et al, 2014) methods. For both determinations, both methods led to the same conclusion regarding the location of the second C atoms in each cage, unambiguously found to be at vertices 12 and 12 0 .…”

Section: Refinementmentioning

confidence: 99%

Synthesis and crystal structures of theracemicandmesoforms of [1-{1′-4′-cyclopentadienyl-4′-cobalta-1′,12′-dicarba-closo-dodecaboranyl(10)}-4-cyclopentadienyl-4-cobalta-1,12-dicarba-closo-dodecaborane(10)], the former as its tetrahydrofuran disolvate

et al. 2015

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Both rac-[1-(1'-4'-Cp-4',1',12'-closo-CoC2B10H11)-4-Cp-4,1,12-closo-CoC2B10H11]·2THF (Cp is cyclopentadienyl and THF is tetrahydrofuran) or [Co2(C5H5)2(C4H22B20)]·2C4H8O, (1), and meso-[1-(1'-4'-Cp-4',1',12'-closo-CoC2B10H11)-4-Cp-4,1,12-closo-CoC2B10H11] or [Co2(C5H5)2(C4H22B20)], (2), were prepared by thermolysis of a rac/meso mixture of the precursor species [1-(1'-4'-Cp-4',1',6'-closo-CoC2B10H11)-4-Cp-4,1,6-closo-CoC2B10H11] and were separated, spectroscopically characterized and studied crystallographically. Cage C-atom identification was accomplished by both the vertex-to-centroid distance and boron-hydrogen distance methods, and, in both cases, the structure established crystallographically is fully consistent with the spectroscopic data. Both the rac-(1) and meso-(2) forms share the same overall conformation (Co-C-C'-Co' ca 136°) and show clear evidence of intramolecular steric crowding resulting in tilted cyclopentadienyl ligands.

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How to Make 8,1,2‐closo‐MC₂B₉ Metallacarboranes

Man¹,

Zlatogorsky²,

Tricas³

et al. 2014

Angewandte Chemie

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Three examples of the rare 8,1,2‐closo‐MC2B9 isomeric form of an icosahedral metallacarborane have been isolated as unexpected trace products in reactions. Seeking to understand how these were formed we considered both the nature of the reactions that were being undertaken and the nature of the coproducts. This led us to propose a mechanism for the formation of the 8,1,2‐closo‐MC2B9 species. The mechanism was then tested, leading to the first deliberate synthesis of an example of this isomer. Thus, deboronation of 4‐(η‐C5H5)‐4,1,8‐closo‐CoC2B10H12 selectively removes the B5 vertex to yield the dianion [nido‐(η‐C5H5)CoC2B9H11]2−, oxidative closure of which affords 8‐(η‐C5H5)‐8,1,2‐closo‐CoC2B9H11 in moderate yield.

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The synthesis and characterisation of homo- and heterobimetallic 1,14,2,9- and 1,14,2,10-M₂C₂B₁₀14-vertex metallacarboranes

Cited by 16 publications

References 29 publications

Balancing Steric and Electronic Effects in Carbonyl–Phosphine Molybdacarboranes

Balancing Steric and Electronic Effects in Carbonyl–Phosphine Molybdacarboranes

Synthesis and crystal structures of theracemicandmesoforms of [1-{1′-4′-cyclopentadienyl-4′-cobalta-1′,12′-dicarba-closo-dodecaboranyl(10)}-4-cyclopentadienyl-4-cobalta-1,12-dicarba-closo-dodecaborane(10)], the former as its tetrahydrofuran disolvate

How to Make 8,1,2‐closo‐MC₂B₉ Metallacarboranes

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The synthesis and characterisation of homo- and heterobimetallic 1,14,2,9- and 1,14,2,10-M2C2B1014-vertex metallacarboranes

Cited by 16 publications

References 29 publications

Balancing Steric and Electronic Effects in Carbonyl–Phosphine Molybdacarboranes

Balancing Steric and Electronic Effects in Carbonyl–Phosphine Molybdacarboranes

Synthesis and crystal structures of theracemicandmesoforms of [1-{1′-4′-cyclopentadienyl-4′-cobalta-1′,12′-dicarba-closo-dodecaboranyl(10)}-4-cyclopentadienyl-4-cobalta-1,12-dicarba-closo-dodecaborane(10)], the former as its tetrahydrofuran disolvate

How to Make 8,1,2‐closo‐MC2B9 Metallacarboranes

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The synthesis and characterisation of homo- and heterobimetallic 1,14,2,9- and 1,14,2,10-M₂C₂B₁₀14-vertex metallacarboranes

How to Make 8,1,2‐closo‐MC₂B₉ Metallacarboranes