Copper(I) complexes of N-centered aliphatic tripodal trithioether ligands – Adjustment of complex geometry by variation of spacer lengths

Blomenkemper, Marc; Schröder, H.; Pape, Tania; Hahn, F. Ekkehardt

doi:10.1016/j.ica.2010.10.008

Cited by 7 publications

(6 citation statements)

References 41 publications

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“…The Cu–N and average Cu–S bond lengths of 2.161(2) and 2.27(2) Å, respectively, observed for 13a are almost identical to the values of 2.17(1) and 2.26(1) Å previously reported for TMMEA–Cu(I), indicating that the pendant sulfopropyl groups have little effect on the Cu(I)–S interactions. The average Cu–N bond in 14a is shorter by 0.036 Å compared with that in 13a , a difference that may be attributed to the greater basicity of the nitrogen in MCL-2 compared with MCL-1 (vide infra); however, the magnitude of the effect is rather modest in view of the variation of the Cu–N bond lengths observed for the Cu(I) complex of ligand 18 , which differed by up to 0.030 Å within the same unit cell …”

Section: Resultsmentioning

confidence: 97%

“…The average Cu-N bond in 14a is shorter by 0.036 Å compared to 13a , a difference that may be attributed to the greater basicity of the nitrogen in MCL-2 compared to MCL-1 ( vide infra ); however, the magnitude of the effect is rather modest in view of the Cu-N bond variations observed for the Cu(I) complex of ligand 18 , which differed by up to 0.030 Å within the same unit cell. 33 …”

Section: Resultsmentioning

confidence: 99%

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Robust Affinity Standards for Cu(I) Biochemistry

et al. 2013

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The measurement of reliable Cu(I) protein binding affinities requires competing reference ligands with similar binding strengths; however, the literature on such reference ligands is not only sparse but often conflicting. To address this deficiency, we have created and characterized a series of water-soluble monovalent copper ligands, MCL-1, MCL-2, and MCL-3, that form well-defined, air-stable, and colorless complexes with Cu(I) in aqueous solution. Concluding from X-ray structural data, electrochemical measurements, and an extensive network of equilibrium titrations, all three ligands form discrete Cu(I) complexes with 1:1 stoichiometry and are capable of buffering Cu(I) concentrations between 10−10 and 10−17 M. As most Cu(I) protein affinities have been obtained from competition experiments with bathocuproine disulfonate (BCS) or 2,2′-bicinchoninic acid (BCA), we further calibrated their Cu(I) stability constants against the MCL-series. To demonstrate the application of these reagents, we determined the Cu(I) binding affinity of CusF (logK = 14.3±0.1), a periplasmic metalloprotein required for the detoxification of elevated copper levels in E. coli. Altogether, this interconnected set of affinity standards establishes a reliable foundation that will facilitate the precise determination of Cu(I) binding affinities of proteins and small molecule ligands.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Robust Affinity Standards for Cu(I) Biochemistry

et al. 2013

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“…Specifically, the first step of the process corresponds to the isolation of known , 2-aminoethyl alkyl sulfides RSCH 2 CH 2 NH 2 by reacting the inexpensive starting materials (bromoethylamine hydrobromide and RSX, where X = Na for R = Me, X = H for R = Ph and Trt; chloroethylamine hydrochloride and BnSH). Alternatively, all RSCH 2 CH 2 NH 2 are commercially available from several vendors; for example, t BuSCH 2 CH 2 NH 2 used in this study was purchased from Enamine, LLC.…”

Section: Results and Discussionmentioning

confidence: 99%

“…MeSCH 2 CH 2 NH 2 , PhSCH 2 CH 2 NH 2 , and t BuSCH 2 CH 2 NH 2 were purchased from Enamine or prepared using modifications of literature procedures (vide infra). BnSCH 2 CH 2 NH 2 was prepared as described elsewhere. All solvents for aerobic organic syntheses were purchased from Sigma-Aldrich and used as received in air in a fume hood.…”

Section: Experimental Sectionmentioning

confidence: 99%

Engineering Catalysts for Selective Ester Hydrogenation

Dub

Batrice

Gordon

et al. 2020

Org. Process Res. Dev.

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The development of efficient catalysts and processes for synthesizing functionalized (olefinic and/or chiral) primary alcohols and fluoral hemiacetals is currently needed. These are valuable building blocks for pharmaceuticals, agrochemicals, perfumes, and so forth. From an economic standpoint, bench-stable Takasago Int. Corp.’s Ru-PNP, more commonly known as Ru-MACHO, and Gusev’s Ru-SNS complexes are arguably the most appealing molecular catalysts to access primary alcohols from esters and H2 (Waser, M. et al. Org. Proc. Res. Dev. 2018, 22, 862). This work introduces economically competitive Ru-SNP(O) z complexes (z = 0, 1), which combine key structural elements of both of these catalysts. In particular, the incorporation of SNP heteroatoms into the ligand skeleton was found to be crucial for the design of a more product-selective catalyst in the synthesis of fluoral hemiacetals under kinetically controlled conditions. Based on experimental observations and computational analysis, this paper further extends the current state-of-the-art understanding of the accelerative role of KO-t-C4H9 in ester hydrogenation. It attempts to explain why a maximum turnover is seen to occur starting at ∼25 mol % base, in contrast to only ∼10 mol % with ketones as substrates.

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“…At the same time, in another report reaction of BnCl with BnNH 2 in water with NaHCO 3 as a base leads to 79 % yield of the Bn 3 N. [22] In 2011 a similar approach was used by Hahn and co-authors in the synthesis of the N-centered aliphatic tripodal trithioether ligands (Scheme 4). [50] Later these ligands were used for the synthesis of Cu complexes. The same approach was used in 2006 by Gleiter and coauthors.…”

Section: N-alkylation With Alkyl Halidesmentioning

confidence: 99%