Recent Advances of Imidazolin-2-iminato in Transition Metal Chemistry

raja, P. Karthick; Revathi, S. K.; Ghatak, Tapas

doi:10.30919/es8d1151

Cited by 4 publications

(5 citation statements)

References 104 publications

(121 reference statements)

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“…The 2-electron redox chemistry observed in A and B is enabled by the unexpected redox noninnocence of the Im Dipp N ligand. Imidazolin-2-iminato ligands have been used extensively to support high-valent, monometallic Ti(IV) complexes. − We reasoned that paring the guanidinate ligand from these systems would favor the formation of multimetallic titanium clusters that, upon reduction, would produce highly reducing species. To this end, reduction of (Im Dipp N)TiCl 3 with sodium amalgam produces the dinuclear Ti(III) complex [Cl 2 Ti(μ-NIm Dipp )] 2 ( 1 ), which can be subsequently reduced to afford [(μ-N-η 6 -Im Dipp )Ti] 2 ( 2 ) and {[(Et 2 O) 2 K](μ-N-μ -η 6 :η 6 -Im Dipp )Ti} 2 ( 3 ).…”

Section: Introductionmentioning

confidence: 99%

Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

et al. 2022

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Reduction of the diamagnetic Ti(III)/Ti(III) dimer [Cl 2 Ti(μ-NIm Dipp )] 2 (1) (NIm Dipp = [1,3-bis(Dipp)imidazolin-2-iminato] − , Dipp = C 6 H 3 -2,6-i Pr 2 ) with 4 and 6 equiv of KC 8 generates the intramolecularly arene-masked, dinuclear titanium compounds [(μ-Nη 6 -Im Dipp )Ti] 2 (2) and {[(Et 2 O) 2 K](μ-N-μ-η 6 :η 6 -Im Dipp )Ti} 2 (3), respectively, in modest yields. The compounds have been structurally characterized by X-ray crystallographic analysis, and inspection of the bond metrics within the η 6 -coordinated aryl substituent of the bridging imidazolin-2-iminato ligand shows perturbation of the aromatic system most consistent with two-electron reduction of the ring. As such, 2 and 3 can be assigned respectively as possessing metal centers in formal Ti(III)/Ti(III) and Ti(II)/Ti(II) oxidation states. Exploration of their redox chemistry reveal the ability to reduce several substrate equivalents. For instance, treatment of 2 with excess C 8 H 8 (COT) forms the novel COTbridged complex [(Im Dipp N)(η 8 -COT)Ti](μ-η 2 :η 3 -COT)[Ti(η 4 -COT)(NIm Dipp )] (4) that dissociates in THF solutions to give mononuclear (Im Dipp N)Ti(η 8 -COT)(THF) (5). Addition of COT to 3 yields heterometallic [(Im Dipp N)(η 4 -COT)Ti(μ-η 4 :η 5 -COT)K(THF)-(μ-η 6 :η 4 -COT)Ti(NIm Dipp )(μ-η 4 :η 4 -COT)K(THF) 2 ] n (6). Compounds 4 and 5 are the products of the 4-electron oxidation of 2, while 6 stands as the 8-electron oxidation product of 3. Reduction of organozides was also explored. Low temperature reaction of 2 with 4 equiv of AdN 3 gives the terminal and bridged imido complex [(Im Dipp N)Ti(�NAd)](μ-NAd) 2 [Ti(NIm Dipp )(N 3 Ad)] (7) that undergoes intermolecular C−H activation of toluene at room temperature to afford the amido compound [(Im Dipp N)Ti-(NHAd)](μ-NAd) 2 [Ti(C 6 H 4 Me)(NIm Dipp )] (8-tol). These complexes are the 6-electron oxidation products of the reaction of 2 with AdN 3 . Furthermore, treatment of 3 with 4 equiv of AdN 3 produces the thermally stable Ti(III)/Ti(III) terminal and bridged imido [K(18-crown-6)(THF) 2 ]{[(Im Dipp N)Ti(NAd)](μ-NAd) 2 K[Ti(NIm Dipp )]} (10). Altogether, these reactions firmly establish 2 and 3 as unprecedented Ti(I)/Ti(I) and Ti(0)/Ti(0) synthons with the clear capacity to effect multielectron reductions ranging from 4 to 8 electrons.

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Section: Introductionmentioning

confidence: 99%

Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

et al. 2022

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“…33 This aspect will be under investigation in due course. In general, these ligands enrich the portfolio of available imidazolin-2-imine systems, which are not only widely used ligands in transition metal, 6 rare earth metal, 19 and actinide chemistry, 23 but have also found considerable attention in main group element chemistry. 34…”

Section: Discussionmentioning

confidence: 99%

“…3–5 The intermediate silylated imines Im R NSiMe 3 may serve as suitable precursors for the preparation of imidazolin-2-iminato transition metal complexes, which feature short metal–nitrogen bonds owing to the ability of these ligands to act as strong 2σ-/4π-electron donors, preferably to early transition metals and/or metals in higher oxidation states. 6 Accordingly, numerous homogeneous d 0 -metal (pre-)catalysts with ancillary imidazolin-2-iminato ligands have been developed, with titanium( iv ) complexes of type I and their use in olefin polymerisation representing the most prominent application (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Titanium complexes with unsymmetrically substituted imidazolin-2-iminato ligands

et al. 2022

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“…Fast Uranium Recovery from Uranium-Containing Solutions in Small Scale. Many highly efficient composite adsorbents have been developed to remove metal ions in wastewater, 63,64 such as extracting hexavalent chromium 65 or rare earth ions, 66 from wastewater with lowconcentration ions. However, there are few good adsorbents for fast and massive uranium recovery from uraniumcontaining wastewater.…”

Section: Uranium Adsorption Performance Of Various Plmrs By Different...mentioning

confidence: 99%

Supramolecularly Poly(amidoxime)-Loaded Macroporous Resin for Fast Uranium Recovery from Seawater and Uranium-Containing Wastewater

Wen

Sun

Liu

et al. 2021

ACS Appl. Mater. Interfaces

108

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Uranium is an extremely abundant resource in seawater that could supply nuclear fuel for over the long-term, but it is tremendously difficult to extract. Here, a new supramolecular poly(amidoxime) (PAO)-loaded macroporous resin (PLMR) adsorbent has been explored for highly efficient uranium adsorption. Through simply immersing the macroporous resin in the PAO solution, PAOs can be firmly loaded on the surface of the nanopores mainly by hydrophobic interaction, to achieve the as-prepared PLMR. Unlike existing amidoxime-based adsorbents containing many inner minimally effective PAOs, almost all the PAOs of PLMR have high uranium adsorption efficiency because they can form a PAO-layer on the nanopores with molecular-level thickness and ultrahigh specific surface area. As a result, this PLMR has highly efficient uranium adsorbing performance. The uranium adsorption capacity of the PLMR was 157 mg/g (the U PAO in the PLMR was 1039 mg/g), in 32 ppm uranium-spiked seawater for 120 h. Additionally, uranium in 1.0 L 100 ppb U-spiked both water and seawater can be removed quickly and the recovery efficiency can reach 91.1 ± 1.7% and 86.5 ± 1.9%, respectively, after being filtered by a column filled with 200 mg PLMR at 300 mL/min for 24 h. More importantly, after filtering 200 T natural seawater with 200 g PLMR for only 10 days, the uranium-uptake amount of the PLMR reached 2.14 ± 0.21 mg/g, and its average uranium adsorption speed reached 0.214 mg/(g·day) which is very fast among reported amidoxime-based adsorbents. This new adsorbent has great potential to quickly and massively recover uranium from seawater and uranium-containing wastewater. Most importantly, this work will provide a simple but general strategy to greatly enhance the uranium adsorption efficiency of amidoxime-functionalized adsorbents with ultrahigh specific surface area via supramolecular interaction, and even inspire the exploration of other adsorbents.

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Recent Advances of Imidazolin-2-iminato in Transition Metal Chemistry

Cited by 4 publications

References 104 publications

Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

Molecular Capacitors: Accessible 6- and 8-Electron Redox Chemistry from Dimeric “Ti(I)” and “Ti(0)” Synthons Supported by Imidazolin-2-Iminato Ligands

Titanium complexes with unsymmetrically substituted imidazolin-2-iminato ligands

Supramolecularly Poly(amidoxime)-Loaded Macroporous Resin for Fast Uranium Recovery from Seawater and Uranium-Containing Wastewater

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