Synthesis and Characterization of GaIII, InIII and LuIII Complexes of a Set of dtpa Bis‐Amide Ligands

Greiser, Julia; Hagemann, Tino; Niksch, Tobias; Traber, Philipp; Kupfer, Stephan; Gräfe, Stefanie; Görls, Helmar; Weigand, Wolfgang; Freesmeyer, Martin

doi:10.1002/ejic.201500436

Cited by 5 publications

(2 citation statements)

References 39 publications

(42 reference statements)

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“…This trend also holds for the smallest metal studied, where mean Lu−N distances decrease modestly from 8a (2.59 Å) to 8b (2.54 Å), showing weak to moderate metal-ligand interactions, respectively (Table S5). 82,83 Taken together, these structures are in agreement with the hypothesis that the strength of the Lewis base-metal interaction serves to mask the charge of the lanthanide to varying degrees.…”

Section: Implications Of the Alkyne Charge Distribution In Cyclizationsupporting

confidence: 85%

Anion Control of Lanthanoenediyne Cyclization

et al. 2019

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A suite of lanthanoenediyne complexes of the form Ln(macrocycle)X 3 (Ln = La 3+ , Ce 3+ , Eu 3+ , Gd 3+ , Tb 3+ , Lu 3+ ; X = NO 3 − , Cl − , OTf −) was prepared by utilizing an enediyne-containing [2 + 2] hexaaza-macrocycle (2). The solid-state Bergman cyclization temperatures, measured via DSC, decrease with the denticity of X (bidentate NO 3 − , T = 267−292 °C; monodentate Cl − , T = 238-262 °C; noncoordinating OTf − , T = 170-183 °C). 13 C NMR characterization shows that the chemical shifts of the acetylenic carbon atoms also rely on the anion identity. The alkyne carbon closest to the metal binding site, C A , exhibits a Δδ > 3 ppm downfield shift, while the more distal alkyne carbon, C B , displays a concomitant Δδ ≤ 2.5 ppm upfield shift, reflecting a depolarization of the alkyne on metal inclusion. For all metals studied, the degree of perturbation follows the trend 2 < NO 3 − < Cl − < OTf −. This belies a greater degree of electronic rearrangement in the coordinated macrocycle as the denticity of X and its accompanying shielding of the metal's Lewis acidity decrease. Computationally modeled structures of LnX 3 show a systematic increase in the lanthanide-2 coordination number (CN La-mc = 2 (NO 3 −), 4 (Cl −), 5 (H 2 O, model for OTf −)) and a decrease in the mean Ln−N bond length (La−N average = 2.91 Å (NO 3 −), 2.78 Å (Cl −), 2.68 Å (H 2 O)), further suggesting that a decrease in the anion coordination number correlates with an increase in the metal-macrocycle interaction. Taken together, these data illustrate a Bergman cyclization landscape that is influenced by the bonding of metal to an enediyne ligand but whose reaction barrier is ultimately dominated by the coordinating ability of the accompanying anion.

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Section: Implications Of the Alkyne Charge Distribution In Cyclizationsupporting

confidence: 85%

Anion Control of Lanthanoenediyne Cyclization

et al. 2019

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“…Lu was chosen as its natural abundance is 97% 175 Lu, giving a good signal in the mass cytometer. Additionally, Lu does not dramatically perturb 1 H NMR spectra. − Quantitative metalation was assumed based on the affinity of DTPA for lanthanides and observations of characteristic changes to the 1 H NMR spectrum upon metalation, which included a general upfield shift and minor peak broadening in peaks corresponding to DTPA as has been reported − (Figure S36: 1 H NMR spectrum of Cy3-Ac-DTPA/Lu-Poly( l -Lys)- 1 ). A final analysis of the 1 H NMR spectra of this polymer was consistent with previous analysis giving approximately 25 monomers bearing the DTPA/Lu chelate, 7 acetylated amides, and on average 1 Cy3 molecule per polymer.…”

Section: Resultsmentioning

confidence: 96%

Design Parameters for a Mass Cytometry Detectable HaloTag Ligand

Potter,

Latour,

Wong

et al. 2023

Bioconjugate Chem.

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Mass cytometry permits the high dimensional analysis of complex biological samples; however, some techniquesare not yet integrated into the mass cytometry workflow due to reagent availability. The use of self-labeling protein systems, such as HaloTag, are one such application. Here, we describe the design and implementation of the first mass cytometry ligands for use with HaloTag. "Click"-amenable HaloTag warheads were first conjugated onto poly(L-lysine) or poly(acrylic acid) polymers that were then functionalized with diethylenetriaminepentaacetic acid (DTPA) lutetium metal chelates. Kinetic analysis of the HaloTag labeling rates demonstrated that the structure appended to the 1chlorohexyl warhead was key to success. A construct with a diethylene glycol spacer appended to a benzamide gave similar rates (k obs ∼ 10 2 M −1 s −1 ), regardless of the nature of the polymer. Comparison of the polymer with a small molecule chelate having rapid HaloTag labeling kinetics (k obs ∼ 10 4 M −1 s −1 ) suggests the polymers significantly reduced the HaloTag labeling rate. HEK293T cells expressing surface-exposed GFP-HaloTag fusions were labeled with the polymeric constructs and 175 Lu content measured by cytometry by time-of-flight (CyTOF). Robust labeling was observed; however, significant nonspecific binding of the constructs to cells was also present. Heavily pegylated polymers demonstrated that nonspecific binding could be reduced to allow cells bearing the HaloTag protein to be distinguished from nonexpressing cells.

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Heteroscorpionate Rare-Earth Catalysts for the Hydroalkoxylation/Cyclization of Alkynyl Alcohols

et al. 2016

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The chiral, enantiopure bis(pyrazol-1-yl)methane-based NNO-donor scorpionate ligands in the form of the alcohol compounds bpzbeH (bpzbe = 1,1-bis(3,5dimethylpyrazol-1-yl)-3,3-dimethyl-2-butoxide), bpzteH (bpzte = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1-p-tolylethoxide), and (R,R)-bpzmmH ((R,R)-bpzmm = (1R)-1-{(1R)-6,6dimethylbicyclo[3.1.1]-2-hepten-2-yl}-2,2-bis(3,5-dimethylpyrazol-1-yl)ethoxide) have been used to obtain new NNOheteroscorpionate yttrium and lutetium complexes. The reactions of bpzbeH, bpzteH (racemic mixtures), and (R,R)-bpzmmH (enantiopure compound) with [M{N(SiHMe 2 ) 2 } 3 (thf) 2 ] (M = Y, Lu) in a 1:1 molar ratio in toluene afforded the mononuclear bis(silylamide) complexes [M{N(SiHMe 2 ) 2 } 2 (κ 3 -NNO)(thf)] (M = Y, Lu; 1−6), respectively. When the reaction was carried out with a 2:1 molar ratio (ligand to metal precursor) or with excess ligand, homoleptic complexes of the type [Y(κ 3 -NNO) 2 (κ-O-NN)] (κ 3 -NNO = κ-O-NN = bpzbe (7), bpzte (8)) were obtained. Compounds 1 and 3 were used as convenient starting materials for the synthesis of the aryloxide and alkoxide yttrium compounds [Y(OR) 2 (κ 3 -bpzbe)] (OR = O-2,6-Me 2 C 6 H 3 (9), O-CH 2 (2-CHC)C 6 H 4 (10)) and [Y(OR) 2 (κ 3 -bpzte)] (OR = O-2,6-Me 2 C 6 H 3 (11), O-CH 2 (2-CHC)C 6 H 4 ( 12)). The structures of the complexes were determined by spectroscopic methods, and the X-ray crystal structures of 1, 2, and 7 were also established. Complexes 1−6 are efficient catalysts for the intramolecular hydroalkoxylation of alkynyl alcohols and give TOF values up to 19.4 h −1 at 90 °C for (2-ethynylphenyl)methanol (13) by using the single enantiopure complex 5 as catalyst, producing exclusively the exo-methylene products. The activation parameters ΔH ⧧ = 19.93(0.2) kcal/mol, ΔS ⧧ = −28.75(0.2) eu, and E a = 18.61(0.2) kcal/mol are consistent with observations for other catalyst-mediated insertive hydroelementation processes.

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Synthesis and Characterization of Ga^III, In^III and Lu^III Complexes of a Set of dtpa Bis‐Amide Ligands

Cited by 5 publications

References 39 publications

Anion Control of Lanthanoenediyne Cyclization

Anion Control of Lanthanoenediyne Cyclization

Design Parameters for a Mass Cytometry Detectable HaloTag Ligand

Heteroscorpionate Rare-Earth Catalysts for the Hydroalkoxylation/Cyclization of Alkynyl Alcohols

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