Synthesis, structural studies and solubility properties of zinc(II), nickel(II) and copper(II) complexes of bulky tris(triazolyl)borate ligands

Bongiovanni, Jessica L.; Rowe, Brittany W.; Fadden, Patrick; Taylor, Michael T.; Wells, Kirsten R.; Kumar, M. Saravana; Papish, Elizabeth T.; Yap, Glenn P. A.; Zeller, Mat­thias

doi:10.1016/j.ica.2010.03.010

Cited by 16 publications

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“…For example, when (Ttz t Bu,Me )ZnCl ( 3 ) is treated with NaOH ( aq ) in CH 3 CN, the isolated organic ligand containing product is (Ttz t Bu,Me )NaOH 2 ( SP‐1 , in this paper SP denotes side products) (Figure , a). This product has been characterized by 1 H and 13 C‐NMR spectra, IR, and X‐ray crystallography (see the Supporting Information for more details).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Biomimetic Zinc Complexes for CO2 Activation and the Influence of Steric Changes in the Ttz Ligands [Ttz = Tris(triazolyl)borate]

et al. 2015

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Carbon dioxide fixation with zinc complexes of the anionic tris(triazolyl)borate (Ttz) ligand offers biomimetic structures in a hydrophilic environment. However, the synthetic result depends greatly on the steric bulk of the Ttz ligand. Synthetic routes adapted from the synthesis of (Tp)ZnOH have been applied to bulky Ttz ligands, but side products often result because Ttz frequently forms complexes with +1 metals or cations used in the synthesis. Nonetheless, (Ttz tBu,Me )-ZnOH (1) has been successfully synthesized and crystallographically characterized, but only via the hydrolysis of the zinc (hex-(1) [a] 2495 Scheme 2. The application of synthetic routes that are known in the literature to form TpZnOH leads to different results when applied to the formation of biomimetic Ttz zinc complexes. However, zinc hydroxide complexes of Ttz can be achieved in some cases. In this Scheme M = Na, K, NMe 4 and L = Tp or Ttz of varied steric bulk (this work focuses on L = Ttz tBu,Me , Ttz iPr2 , Ttz Ph,Me ). 2496Scheme 3. Successful route to (Ttz tBu,Me )ZnOH (1) via Zn amide (6). Zn amide structure is tentatively assigned as κ 3 or κ 2 .Scheme 4. Synthesis of the zinc hydroxide (2a) and zinc carbonate (2b) complexes. Two equivalents of 2a react with CO 2 to eliminate water and form one equivalent of 2b.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Biomimetic Zinc Complexes for CO2 Activation and the Influence of Steric Changes in the Ttz Ligands [Ttz = Tris(triazolyl)borate]

et al. 2015

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“…The syntheses of the complexes (1-6) in Figure 4 [Htz tBu,Me , H(Ttz tBu,Me ), K(Ttz tBu,Me ), (Ttz tBu,Me )ZnCl, (Ttz tBu,Me )CuCl, and (Ttz tBu,Me )Cu(NO 2 )] were carried out according to literature procedures (Scheme 1). [8,31,34,35] and NaNO 2 (Sigma Aldrich) were used as received.…”

Section: Methodsmentioning

confidence: 99%

“…The complexes used in this study have been made previously (by the routes in Scheme 1) and were synthesized by known methods. [8,31,34,35] These are copper and zinc complexes [(Ttz tBu,Me )CuCl (1), (Ttz tBu, Me )CuNO 2 (2), (Ttz tBu,Me )ZnCl (3)] which allow us to contrast a redox active metal (copper) with a redox inactive metal (zinc). Furthermore, K(Ttz tBu,Me ) (4), (Ttz tBu,Me )H (5), and Htz tBu, Me (6) allow us to probe the electrochemical behavior of the free triazole rings.…”

Section: Synthesismentioning

confidence: 99%

“…[38][39][40][41][42][43][44][45][46] Unlike Ttz, Tp complexes have poor water solubility and are sensitive to acids, thus preventing their use as catalysts in water, alcohols, or acidic solutions. Ttz R,R' is a weaker electron donor compared to Tp R,R' , [35,47] as evident from the difference in CO stretching frequencies (solid state) for (Ttz tBu,Me )Cu I CO (2080 cm -1 ) and (Tp tBu,Me )Cu I CO (2060 cm -1 ). [30] Figure 2: General structure of Tp R,R' (left) and Ttz R,R' (right).…”

Section: Introductionmentioning

confidence: 98%

“…Bulky tris(3,5-R,R'-1, 2, 4-triazolyl)borate (Ttz R,R' ) ligands support low coordinate metalcenters that are suitable for catalysis. [8,[29][30][31][32][33][34][35][36][37] Ttz complexes of copper(I) show that electrophilic C-H activation reactions can be enhanced by ligand protonation. [29] Ttz ligands offer facial coordination and ease of steric modification at the metal center similar to the more commonly used tris(3-R-5-R'-1,2-pyrazolyl)hydroborate (Tp R,R' ) ligands ( Figure 2).…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical reduction of Ttz copper(II) complexes in the presence and absence of protons: Processes relevant to enzymatic nitrite reduction (TtzR,R′= tris(3-R, 5-R′-1, 2, 4-triazolyl)borate)

Siek

Dixon

Papish

2017

Inorganica Chimica Acta

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Tris(triazolyl)borate (Ttz) is a proton responsive ligand, and the redox potential of Ttz complexes can be altered by protonation. Protonation events can therefore alter the thermodynamics of reduction of copper complexes, and this is relevant to nitrite reduction mediated by copper complexes wherein Cu(II) reduction to Cu(I) is the first step. The electrochemical behavior of tris(triazolyl)borate and the corresponding copper complexes, Ttz tBu,Me CuCl (1) and Ttz tBu,Me CuNO 2 (2), was investigated under both neutral and acidic conditions. Upon protonation, reduction of 1 is shifted more positive (E pc = 290 mV) upon addition of 1.0 equiv. of acid. This result indicates that ligand protonation facilitates the reduction process, which is also evident from the UV-Vis spectral data. In contrast, with the Ttz tBuMe CuNO 2 (2) analogue, the reduction peak shifted towards a more negative potential while UV-Vis spectra shows no significant changes as acid is added. This suggests that the protons may not be involved in assisting the redox process but rather lead to decomposition events at reducing potentials. Other electrochemical control studies on a series of compounds, namely (Ttz tBu,Me)ZnCl (3), (Ttz tBu,Me)K (4), H(Ttz tBu,Me) (5), and Htz tBu,Me (6), were also conducted with and without acid present. These studies have shown that triazole rings, by themselves and in metal complexes, are not redox active under the conditions we have used. We therefore conclude that the Ttz ligand (including in 1 and 2) is not a site for reduction in our studies.

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Synthesis and Characterization of Tris(oxazolinyl)borato Copper(II) and Copper(I) Complexes

Sadow

Eedugurala

Wang

et al. 2021

Helvetica Chimica Acta

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The reaction of ToMTl (ToM=tris(4,4‐dimethyl‐2‐oxazolinyl)phenylborate) and CuBr2 in benzene at 60 °C provides ToMCuBr (1) as an entry‐point into tris(oxazolinyl)phenylborato copper chemistry. ToMCuOtBu (2) and ToMCuOAc (3) are prepared by the reactions of ToMCuBr with KOtBu and NaOAc, respectively. ToMCuOtBu is transformed into (ToMCuOH)2 (4) through hydrolysis. NMR, FT‐IR, and EPR spectroscopies are used to determine the electronic and structural properties of these copper(II) compounds, and the solid‐state structures were characterized by X‐ray crystallography. Reduction of copper is observed upon treatment of ToMCuOtBu with phenylsilane in an attempt to synthesize monomeric copper(II) hydride. ToMCu (5) and ToM2Cu (6) were independently synthesized and characterized for comparison.

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Synthesis, structural studies and solubility properties of zinc(II), nickel(II) and copper(II) complexes of bulky tris(triazolyl)borate ligands

Cited by 16 publications

References 57 publications

Synthesis of Biomimetic Zinc Complexes for CO2 Activation and the Influence of Steric Changes in the Ttz Ligands [Ttz = Tris(triazolyl)borate]

Synthesis of Biomimetic Zinc Complexes for CO2 Activation and the Influence of Steric Changes in the Ttz Ligands [Ttz = Tris(triazolyl)borate]

Electrochemical reduction of Ttz copper(II) complexes in the presence and absence of protons: Processes relevant to enzymatic nitrite reduction (TtzR,R′= tris(3-R, 5-R′-1, 2, 4-triazolyl)borate)

Synthesis and Characterization of Tris(oxazolinyl)borato Copper(II) and Copper(I) Complexes

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