Synthesis, Structures, and Reactivity of Four-Electron-Donor η<sup>2</sup>-Organonitrile, Carbonyl Oxo, and Carbonyl Thio Complexes of Tungsten

Thomas, Simon; Tiekink, Edward R. T.; Young, Charles G.

doi:10.1021/om960083l

Cited by 50 publications

(55 citation statements)

References 24 publications

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“…This MO bears a strong analogy to cis -W IV O(CO) species in which oxo and carbonyl ligands interact in a synergistic way with the same tungsten d orbital as π donor and π acid ( Figure S49 ). 84 Thus, tungsten L 1 -edge XAS complements the S K-edge data, which only provides the dithiolene sulfur contribution to the frontier MOs.…”

Section: Resultsmentioning

confidence: 99%

X-ray Absorption Spectroscopy Systematics at the Tungsten L-Edge

et al. 2014

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A series of mononuclear six-coordinate tungsten compounds spanning formal oxidation states from 0 to +VI, largely in a ligand environment of inert chloride and/or phosphine, was interrogated by tungsten L-edge X-ray absorption spectroscopy. The L-edge spectra of this compound set, comprised of [W0(PMe3)6], [WIICl2(PMePh2)4], [WIIICl2(dppe)2][PF6] (dppe = 1,2-bis(diphenylphosphino)ethane), [WIVCl4(PMePh2)2], [WV(NPh)Cl3(PMe3)2], and [WVICl6], correlate with formal oxidation state and have usefulness as references for the interpretation of the L-edge spectra of tungsten compounds with redox-active ligands and ambiguous electronic structure descriptions. The utility of these spectra arises from the combined correlation of the estimated branching ratio of the L3,2-edges and the L1 rising-edge energy with metal Zeff, thereby permitting an assessment of effective metal oxidation state. An application of these reference spectra is illustrated by their use as backdrop for the L-edge X-ray absorption spectra of [WIV(mdt)2(CO)2] and [WIV(mdt)2(CN)2]2– (mdt2– = 1,2-dimethylethene-1,2-dithiolate), which shows that both compounds are effectively WIV species even though the mdt ligands exist at different redox levels in the two compounds. Use of metal L-edge XAS to assess a compound of uncertain formulation requires: (1) Placement of that data within the context of spectra offered by unambiguous calibrant compounds, preferably with the same coordination number and similar metal ligand distances. Such spectra assist in defining upper and/or lower limits for metal Zeff in the species of interest. (2) Evaluation of that data in conjunction with information from other physical methods, especially ligand K-edge XAS. (3) Increased care in interpretation if strong π-acceptor ligands, particularly CO, or π-donor ligands are present. The electron-withdrawing/donating nature of these ligand types, combined with relatively short metal–ligand distances, exaggerate the difference between formal oxidation state and metal Zeff or, as in the case of [WIV(mdt)2(CO)2], exert the subtle effect of modulating the redox level of other ligands in the coordination sphere.

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Section: Resultsmentioning

confidence: 99%

X-ray Absorption Spectroscopy Systematics at the Tungsten L-Edge

et al. 2014

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“…Mono‐oxo carbonyl complexes of W IV and Mo IV reported by Mayer et al 1d,f,h,i. and Young et al 1a–c,e. as well as theoretical studies by Mingos and co‐workers1g highlight the importance of these complexes.…”

Section: Methodsmentioning

confidence: 90%

Concurrent Stabilization of π‐Donor and π‐Acceptor Ligands in Aromatized and Dearomatized Pincer [(PNN)Re(CO)(O)₂] Complexes

et al. 2014

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Aromatized cationic [(PNN)Re(π acid)(O)2](+) (1) and dearomatized neutral [(PNN*)Re(π acid)(O)2] (2) complexes (where π acid=CO (a), tBuNC (b), or (2,6-Me2)PhNC (c)), possessing both π-donor and π-acceptor ligands, have been synthesized and fully characterized. Reaction of [(PNN)Re(O)2](+) (4) with lithiumhexamethyldisilazide (LiHMDS) yield the dearomatized [(PNN*)Re(O)2] (3). Complexes 1 and 2 are prepared from the reaction of 4 and 3, respectively, with CO or isocyanides. Single-crystal X-ray structures of 1 a and 1 b show the expected trans-dioxo structure, in which the oxo ligands occupy the axial positions and the π-acidic ligand occupies the equatorial plane in an overall octahedral geometry about the rhenium(V) center. DFT studies revealed the stability of complexes 1 and 2 arises from a π-backbonding interaction between the d(xy) orbital of rhenium, the π orbital of the oxo ligands, and the π* orbital of CO/isocyanide.

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“…In a similar vein, the active centers in tungsten-containing enzymes such as aldehyde oxidoreductase and formate dehydrogenase [55,56] have been modeled using a variety of Tp RR 0 complexes [52,57], as exemplified by an ene-1,2-dithiolate complex (Fig. 5) described by Young and coworkers [58].…”

Section: Tris(pyrazolyl)boratesmentioning

confidence: 99%

Synthetic Bioinorganic Chemistry: Scorpionates Turn 50

Rabinovich

2016

Structure and Bonding

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The coordination chemistry of scorpionates, anionic tripodal boroncentered ligands that readily bind to virtually all main group, transition, and f-block metals, has had a profound effect in the development of synthetic bioinorganic chemistry during the past 50 years. Highlighted in this article are some of the most meaningful results published in the area, primarily in the preparation of structural and functional model compounds for the active sites in metalloproteins and metalloenzymes, a theme that encompasses topics as diverse as nitrogen fixation and heavy metal poisoning. It has also been 50 years since the genesis of Structure and Bonding, so let this account also be a celebration of the many contributions that the staunch serial has had on the entire field of inorganic chemistry during the past half century.

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Synthesis, Structures, and Reactivity of Four-Electron-Donor η²-Organonitrile, Carbonyl Oxo, and Carbonyl Thio Complexes of Tungsten

Cited by 50 publications

References 24 publications

X-ray Absorption Spectroscopy Systematics at the Tungsten L-Edge

X-ray Absorption Spectroscopy Systematics at the Tungsten L-Edge

Concurrent Stabilization of π‐Donor and π‐Acceptor Ligands in Aromatized and Dearomatized Pincer [(PNN)Re(CO)(O)₂] Complexes

Synthetic Bioinorganic Chemistry: Scorpionates Turn 50

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Synthesis, Structures, and Reactivity of Four-Electron-Donor η2-Organonitrile, Carbonyl Oxo, and Carbonyl Thio Complexes of Tungsten

Cited by 50 publications

References 24 publications

X-ray Absorption Spectroscopy Systematics at the Tungsten L-Edge

X-ray Absorption Spectroscopy Systematics at the Tungsten L-Edge

Concurrent Stabilization of π‐Donor and π‐Acceptor Ligands in Aromatized and Dearomatized Pincer [(PNN)Re(CO)(O)2] Complexes

Synthetic Bioinorganic Chemistry: Scorpionates Turn 50

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Synthesis, Structures, and Reactivity of Four-Electron-Donor η²-Organonitrile, Carbonyl Oxo, and Carbonyl Thio Complexes of Tungsten

Concurrent Stabilization of π‐Donor and π‐Acceptor Ligands in Aromatized and Dearomatized Pincer [(PNN)Re(CO)(O)₂] Complexes