.omicron.-Quinone coordination to cis-dioxomolybdenum(VI) species.  Crystal and molecular structure of cis-dioxodichloro(9,10-phenanthrenequinone)molybdenum(VI)

Pierpont, Cortlandt G.; Downs, Hartley H.

doi:10.1021/ic50177a064

Cited by 32 publications

(11 citation statements)

References 5 publications

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“…The structures determined may be termed distorted octahedral, partly because of the specific requirements of the strong π‐donor oxo‐ and/or sulfido‐ligands. These active sites fit well the category of d 0 dioxo complexes discussed above (Section 4.3), and a considerable number of synthetic model complexes has been structurally characterized211, 212 or studied computationally 211, 219…”

Section: Heteroleptic Systemssupporting

confidence: 57%

“…These conclusions are consistent with more general notions about the alleviation, by structural distortions, of conflicts between different π‐donor ligands (or between σ‐ and π‐donor ligands) competing for a given set of metal d orbitals 211. The prototypical example for this type of competition is that discussed for distorted octahedral dioxomolybdenum complexes, in which the two strong π‐donor oxo ligands prefer a cisoid arrangement (Section 3.8), and the two weakest co‐ligands are located trans to the oxo ligands, with typically small angles between them211a, 212 (see also ref. 179 for a theoretical study on a cis diimido complex).…”

Section: Heteroleptic Systemsmentioning

confidence: 99%

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“Non‐VSEPR” Structures and Bonding in d⁰Systems

Kaupp

2001

Angewandte Chemie Intl Edit

173

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Under certain circumstances, metal complexes with a formal d0 electronic configuration may exhibit structures that violate the traditional structure models, such as the VSEPR concept or simple ionic pictures. Some examples of such behavior, such as the bent gas‐phase structures of some alkaline earth dihalides, or the trigonal prismatic coordination of some early transition metal chalcogenides or pnictides, have been known for a long time. However, the number of molecular examples for “non‐VSEPR” structures has increased dramatically during the past decade, in particular in the realm of organometallic chemistry. At the same time, various theoretical models have been discussed, sometimes controversially, to explain the observed, unusual structures. Many d0 systems are important in homogeneous and heterogeneous catalysis, biocatalysis (e.g. molybdenum or tungsten enzymes), or materials science (e.g. ferroelectric perovskites or zirconia). Moreover, their electronic structure without formally nonbonding d orbitals makes them unique starting points for a general understanding of structure, bonding, and reactivity of transition metal compounds. Here we attempt to provide a comprehensive view, both of the types of deviations of d0 and related complexes from regular coordination arrangements, and of the theoretical framework that allows their rationalization. Many computational and experimental examples are provided, with an emphasis on homoleptic mononuclear complexes. Then the factors that control the structures are discussed in detail. They are a) metal d orbital participation in σ bonding, b) polarization of the outermost core shells, c) ligand repulsion, and d) π bonding. Suggestions are made as to which of the factors are the dominant ones in certain situations. In heteroleptic complexes, the competition of σ and π bonding of the various ligands controls the structures in a complicated fashion. Some guidelines are provided that should help to better understand the interrelations. Bent's rule is of only very limited use in these types of systems, because of the paramount influence of π bonding. Finally, computed and measured structures of multinuclear complexes are discussed, including possible consequences for the properties of bulk solids.

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Section: Heteroleptic Systemssupporting

confidence: 57%

Section: Heteroleptic Systemsmentioning

confidence: 99%

“Non‐VSEPR” Structures and Bonding in d⁰Systems

Kaupp

2001

Angewandte Chemie Intl Edit

173

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“…The phenC-O 2 analogue, 6,c rystallises as dichroicg reen/ yellow plates with X-ray data modelled in the triclinic space group P1 .T he YbÀO1/O2 bond lengths of 2.234(2) and 2.229(2) ,r espectively,i ndicate that the unencumbered/rigid phenC-O 2 ligand adopts as ymmetric coordination,w hichh as also been observed in transition-metal phenC-O 2 ketyl complexes. [23] Examination of the tbbqC-O 2 and the phenC-O 2 chelating sites, featuring the binding of the O1,C51/C52,O2 atoms, shows that they are near-aromatic in nature with each bond length lying between ad ouble and single bond,a st hey have shorter CÀCb ond lengths and longer CÀOb ond lengths than observed in the respective diketones (tbbq:C 51ÀC52: 1.551(2) ,a verage:C =O: 1.217 , [24] and phen:C 51ÀC52:c a. 1.532 ,a verage:C =O: 1.221 ).…”

Section: Reduction Of 12-diketones By Ad Ivalent Ytterbium Formamidimentioning

confidence: 99%

Bulky Ytterbium Formamidinates Stabilise Complexes with Radical Ligands, and Related Samarium “Tetracyclone” Chemistry

Werner

Zhao

Best

et al. 2017

Chemistry A European J

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Divalent [Yb(DippForm) (thf) ] (n=2 (1 a), or 1 (1 b), DippForm=N,N'-bis(2,6-diisopropylphenyl)formamidinate) complexes were treated with the ketones: 9-fluorenone (fn), or 2,3,4,5-tetraphenylcyclopentadienone (tpc, tetracyclone), giving ketyl complexes: [Yb(DippForm) (fn -O)(thf)] (2), and [Yb(DippForm) (tpc -O)] (3), respectively (ketyl=a radical anion containing a C -O group. By contrast, when perfluorobenzophenone (pfb) was treated with either 1 a or 1 b, transitory ketyl formation was followed by rapid decomposition through a C-F activation pathway, giving [YbF(DippForm) (thf)] (4 a) and a highly unusual fluoride/oxide-bridged species: [Yb F O (DippForm) ] (4 b). The reduction of diketones: 3,5-di-tert-butyl-1,2-benzoquinone (tbbq), 9,10-phenanthrenequinone (phen), or 1,2-acenaphthenequinone (acen), was also examined giving ketyl complexes: [Yb(DippForm) (tbbq -O )] (5), [Yb(DippForm) (phen -O )] (6), and [Yb(DippForm) (acen -O )(thf)] (7). An unsolvated derivative of 7, namely [Yb(DippForm) (acen -O )] (8), was obtained from PhMe. All ketyl complexes had suitably elongated C -O bonds, were stable in both polar and non-polar solvents-an uncommon trait for rare-earth ketyl complexes-and, with the exception of 3, showed radical signals in ESR spectra. To investigate the reactivity of the tpc -O ketyl complex, 3 was treated with oxidants (CS , Se) and reducing agents (Mg , KH, or [SmI (thf) ]). Thus 3 was oxidised to tpc by Se. Treatment of 3 with KH led to a ligand exchange process giving an unusual diketyl species [Yb(DippForm)(tpc -O) (thf) ] (10), which has two cisoid tpc -O ligands in very close proximity. When treated with [SmI (thf) ], the tpc -O ketyl was further reduced to a dianion (1-oxido-2,3,4,5-tetraphenylcyclopentadianide ), ({C Ph }-O) by [SmI (thf) ], giving dimeric [{SmI({C Ph }-O)(thf) } ] (Sm11) and monomeric complexes [YbI(DippForm) (thf)] (11 b) and [YbI (DippForm)(thf) ] (11 c). Activated Sm metal reduced neutral tetracyclone to the dianion, ({C Ph }-O) , in THF, giving tetranuclear [{Sm ({C Ph }-O) (thf) } ] (Sm13). Treatment of Sm13 with iodine in situ provided access to [{SmI({C Ph }-O)(thf) } ] (Sm11), in good yield.

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“…The detailed analysis of X-ray data on transition metals o-quinono (Q), o-semiquinonato (SQ) and catecholate (Cat) complexes has shown that lengths of C-O and C-C bonds of the chelate ring are sensitive to the oxidation level of ligand [1,2,4,5,13,15,19,32,33]. The C-O distance in catecholate complexes varies in the range of 1.32-1.39Å, while the C-C bond of the hexatomic carbon ring is close to aromatic one and has an average value of 1.39-1.41Å; for semiquinonato complexes these values are: C-O 1.28-1.31Å, C-C 1.42-1.45Å; for complexes with neutral quinones [33] the C-O bond lengths is ∼1.23Å, and C-C is ∼1.53Å.…”

Section: General Remarksmentioning

confidence: 99%

“…The C-O distance in catecholate complexes varies in the range of 1.32-1.39Å, while the C-C bond of the hexatomic carbon ring is close to aromatic one and has an average value of 1.39-1.41Å; for semiquinonato complexes these values are: C-O 1.28-1.31Å, C-C 1.42-1.45Å; for complexes with neutral quinones [33] the C-O bond lengths is ∼1.23Å, and C-C is ∼1.53Å. These parameters are helpful in the determination of electronic configuration of high-spin complexes containing one or more o-quinone ligands.…”

Section: General Remarksmentioning

confidence: 99%

Transition metal complexes with bulky 4,6-di-tert-butyl-N-aryl(alkyl)-o-iminobenzoquinonato ligands: Structure, EPR and magnetism

Poddel’sky

Cherkasov

Abakumov

2009

Coordination Chemistry Reviews

325

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.omicron.-Quinone coordination to cis-dioxomolybdenum(VI) species. Crystal and molecular structure of cis-dioxodichloro(9,10-phenanthrenequinone)molybdenum(VI)

Cited by 32 publications

References 5 publications

“Non‐VSEPR” Structures and Bonding in d⁰Systems

“Non‐VSEPR” Structures and Bonding in d⁰Systems

Bulky Ytterbium Formamidinates Stabilise Complexes with Radical Ligands, and Related Samarium “Tetracyclone” Chemistry

Transition metal complexes with bulky 4,6-di-tert-butyl-N-aryl(alkyl)-o-iminobenzoquinonato ligands: Structure, EPR and magnetism

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.omicron.-Quinone coordination to cis-dioxomolybdenum(VI) species. Crystal and molecular structure of cis-dioxodichloro(9,10-phenanthrenequinone)molybdenum(VI)

Cited by 32 publications

References 5 publications

“Non‐VSEPR” Structures and Bonding in d0Systems

“Non‐VSEPR” Structures and Bonding in d0Systems

Bulky Ytterbium Formamidinates Stabilise Complexes with Radical Ligands, and Related Samarium “Tetracyclone” Chemistry

Transition metal complexes with bulky 4,6-di-tert-butyl-N-aryl(alkyl)-o-iminobenzoquinonato ligands: Structure, EPR and magnetism

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“Non‐VSEPR” Structures and Bonding in d⁰Systems

“Non‐VSEPR” Structures and Bonding in d⁰Systems