Pentamethylcyclopentadienyl‐tantal(V)‐Komplexe (Cp*Ta) mit 1, 2, 3‐Triazolato‐Liganden

Herberhold, Max; Goller, Achim; Milius, Wolfgang

doi:10.1002/zaac.200300025

Cited by 14 publications

(4 citation statements)

References 12 publications

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“…To further complete the characterization of the 1,3-dipole Ti azide moieties in complex 7 , its potential reactivity toward organic dipolarophiles was explored. The [3 + 2] cycloaddition reactions between metal azide complexes and dipolarophiles (known as the “i-click” (inorganic click) reaction and mostly studied with activated alkynes) leading to monodentate anionic 1,2,3-triazolate (Tz) metal complexes are well-known for most of the transition-metal azide complexes (Ta, Mo, Mn, Re, Fe, Ru, , Os, Co, Rh, Ir, Ni, , Pd , ), but are still unexplored for d 0 group 4 metal azide complexes. The reaction of the NHC titanium azide complex 7 with a 5-fold excess of DMAD (=dimethyl acetylenedicarboxylate) in dichloromethane at room temperature afforded the titanium bis-triazolato complex 8 (Scheme ) along with a minor impurity (∼10%), unreacted DMAD, and methanotriazoles CH 2 (Tz) 2 and CH(Tz) 3 arising from the reaction between chlorinated solvent and Ti–N 3 forming azidomethanes, which subsequently react with DMAD) .…”

Section: Resultsmentioning

confidence: 99%

Structural Characterization of Tridentate N-Heterocyclic Carbene Titanium(IV) Benzyloxide, Silyloxide, Acetate, and Azide Complexes and Assessment of Their Efficacies for Catalyzing the Copolymerization of Cyclohexene Oxide with CO₂

et al. 2017

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The reactivity of tridentate bis-aryloxy N-heterocyclic carbene (NHC) titanium complexes ([κ 3 -O,C,O]-NHC)-Ti(X 1 )(X 2 ) (X 1 = X 2 = Cl (1); X 1 = X 2 = OiPr (2)) via salt metathesis (with LiOBn, NaOAc), protonolysis (with (tBuO) 3 SiOH), and σ-bond metathesis (with Me 3 SiN 3 ) were investigated, leading to a series of NHC titanium complexes bearing various X and XL type coligands, ([The molecular structures of complexes 3 and 5 were identified by X-ray crystallographic studies, disclosing fivecoordinate complexes, while complexes 4 and 7 crystallize only in the presence of THF, leading to the six-coordinate Ti−THF adducts ([κ 3 -O,C,O]-NHC)Ti(X 1 )(X 2 )(THF) (4-THF and 7-THF). In contrast, the structure of 6 reveals a rare example of a seven-coordinate Ti complex in which the tridentate NHC and two bidentate OAc ligands are coordinated in a pentagonal-bipyramidal fashion around the titanium atom. The reactivity of the 1,3-dipole Ti azide 7 was also further carried out via a [3 + 2] cycloaddition reaction with the dipolarophile dimethyl acetylenedicarboxylate, exhibiting a unique coordination mode for the newly formed triazolato (Tz) ligands to titanium 8 (i.e., as ([κ 1 -N 1 ]-Tz)). Attempts to access NHC-Ti(III) species from the reduction of 1 with LiBEt 3 H•THF lead mainly to ([κ 5 -O,N,C,N,O]-imidazolidine)Ti(Cl)(THF) (9) via hydride transfer to the NHC carbene atom. The fully characterized NHC-Ti complexes 1−7 were evaluated for the copolymerization of cyclohexene oxide with CO 2 . Upon the addition of [PPN]X cocatalysts (with X = Cl, N 3 ), all of the complexes are active at low CO 2 pressure (<0.5 bar) and are highly selective (>99%) toward the formation of atactic poly(cyclohexene oxide-alt-carbonate). While the variation of the coligands has an overall moderate effect on the activity, the results mostly indicate that, in the presence of [PPN]Cl ([PPN] = (Ph 3 P) 2 N), the sterically less hindered coligands in NHC-Ti(IV) isopropoxide, azide, and acetate complexes show better activity with turnovers up to 930 in comparison to other bulky coligands. On the other hand, when the more nucleophilic [PPN]N 3 salt is employed, the sterically more hindered complexes 2−6 show an increase in activity by approximatively 20%, whereas the less encumbered complexes 1 and 7 exhibit a decrease in activity.

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Section: Resultsmentioning

confidence: 99%

Structural Characterization of Tridentate N-Heterocyclic Carbene Titanium(IV) Benzyloxide, Silyloxide, Acetate, and Azide Complexes and Assessment of Their Efficacies for Catalyzing the Copolymerization of Cyclohexene Oxide with CO₂

et al. 2017

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“…The construction of the solution stable oligomers in part comes from employing inorganic click chemistry (iClick) . iClick originally appeared in the literature to describe the cycloaddition between a metal-azide and a metal-acetylide according to eq . , Cycloadditions between metal-azides − or metal-acetylides and their organic counterparts ,,− are now cited ,, as iClick reactions as well. When M = Au(I) and L = small phosphine, the dinuclear triazolate complex dimerizes via aurophilic bonding to give tetranuclear clusters illustrated in eq .…”

Section: Introductionmentioning

confidence: 99%

An Application Exploiting Aurophilic Bonding and iClick to Produce White Light Emitting Materials

et al. 2020

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The paper focuses on exploiting aurophilic bonding to produce white light emitting materials. Inorganic Click (iClick) is employed to link two or four Au(I) metal ions through a triazolate bridge. Depending on the choice of phosphine ligand (PEt3 or PPh3), dinuclear Au2-FO or tetranuclear Au4-FO complexes can be controllably synthesized (FO = 2-(9,9-dioctylfluoreneyl-)). The iClick products Au2-FO and Au4-FO are characterized by combustion analysis and multinuclear NMR, TOCSY 1D, 1H–13C gHMBC, and 1H–13C gHSQC. In addition, the photophysical properties of Au2-FO and Au4-FO were examined in THF solution. Transient absorption spectroscopy was employed to elucidate the excited state features of the gold compounds. Solution processed OLEDs were fabricated and characterized, which gave white light electroluminescence with CIE coordinates (0.34, 0.36), as seen referenced to CIE standard illuminant D65 (0.31, 0.32). TDDFT computational analysis of Au2-FO and Au4-FO reveals the origin of light emission. In the case of Au4-FO, direct excitation leads to increased aurophilic bonding in the excited state, and as a result the emission profile is broadened to cover a larger region of the visible spectrum, thus giving white light emission. Designing molecules that can access or increase aurophilic bonding in the excited state provides another tool for fine-tuning the emission profiles of gold complexes.

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“…Metal-azides from all three rows of the transition metal series ([M]-N 3 where M = Fe, Co, − Ni, , Ta, Ru, − Mn, Os, Mo, and Au) can undergo thermal ( not Cu-catalyzed) azide–alkyne cycloaddition to provide M-triazolate complexes. In most cases, the alkynes are either electron deficient, such as dimethyl-but-2-ynedioate, or highly strained, such as cyclooctyne and its derivatives.…”

Section: Introductionmentioning

confidence: 99%

Single versus Double Cu(I) Catalyzed [3 + 2] Azide/Platinum Diacetylide Cycloaddition Reactions

et al. 2017

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This report focuses on Cu(I) catalyzed cycloaddition reactions between organic azides and the platinum diacetylide complexes trans-(PR3)2Pt(CCR′)2 (where PR3 = P(OEt)3, PEt3, P n Bu3, PPhMe2, PPh3, and PBn3; and R′ = H, Ph, and p-PhNO2). Pt(II)-Diacetylides supported by P(OEt)3, PEt3, P n Bu3, and PPhMe2 react with benzyl azide to provide syn/anti isomers of double cycloaddition products. In contrast, Pt(II)-diacetylide complexes supported by PPh3 and PBn3 afford single cycloaddition products, exclusively. Steric congestion enforced by the larger phosphines PPh3 and PBn3 prevent the second cycloaddition. Ground state DFT computations provide some insight into the divergent reactivity and indicate that the π-acidity of the phosphine ligands is a variable in the single vs double cycloaddition outcome.

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Pentamethylcyclopentadienyl‐tantal(V)‐Komplexe (Cp*Ta) mit 1, 2, 3‐Triazolato‐Liganden

Cited by 14 publications

References 12 publications

Structural Characterization of Tridentate N-Heterocyclic Carbene Titanium(IV) Benzyloxide, Silyloxide, Acetate, and Azide Complexes and Assessment of Their Efficacies for Catalyzing the Copolymerization of Cyclohexene Oxide with CO₂

Structural Characterization of Tridentate N-Heterocyclic Carbene Titanium(IV) Benzyloxide, Silyloxide, Acetate, and Azide Complexes and Assessment of Their Efficacies for Catalyzing the Copolymerization of Cyclohexene Oxide with CO₂

An Application Exploiting Aurophilic Bonding and iClick to Produce White Light Emitting Materials

Single versus Double Cu(I) Catalyzed [3 + 2] Azide/Platinum Diacetylide Cycloaddition Reactions

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Pentamethylcyclopentadienyl‐tantal(V)‐Komplexe (Cp*Ta) mit 1, 2, 3‐Triazolato‐Liganden

Cited by 14 publications

References 12 publications

Structural Characterization of Tridentate N-Heterocyclic Carbene Titanium(IV) Benzyloxide, Silyloxide, Acetate, and Azide Complexes and Assessment of Their Efficacies for Catalyzing the Copolymerization of Cyclohexene Oxide with CO2

Structural Characterization of Tridentate N-Heterocyclic Carbene Titanium(IV) Benzyloxide, Silyloxide, Acetate, and Azide Complexes and Assessment of Their Efficacies for Catalyzing the Copolymerization of Cyclohexene Oxide with CO2

An Application Exploiting Aurophilic Bonding and iClick to Produce White Light Emitting Materials

Single versus Double Cu(I) Catalyzed [3 + 2] Azide/Platinum Diacetylide Cycloaddition Reactions

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Structural Characterization of Tridentate N-Heterocyclic Carbene Titanium(IV) Benzyloxide, Silyloxide, Acetate, and Azide Complexes and Assessment of Their Efficacies for Catalyzing the Copolymerization of Cyclohexene Oxide with CO₂

Structural Characterization of Tridentate N-Heterocyclic Carbene Titanium(IV) Benzyloxide, Silyloxide, Acetate, and Azide Complexes and Assessment of Their Efficacies for Catalyzing the Copolymerization of Cyclohexene Oxide with CO₂