Dataset Information

Linking of Cu^I Units by Tetrahedral Mo₂ E₂ Complexes (E=P, As).

ABSTRACT: The reaction of [Cp₂ Mo₂ (CO)₄ (?,?^2:2 -E₂ )] (A: E=P, B: E=As, Cp=C₅ H₅ ) with the WCA-containing Cu^I salts ([Cu(CH₃ CN)₄ ][Al{OC(CF₃ )₃ }₄ ] (CuTEF, C), [Cu(CH₃ CN)₄ ][BF₄ ] (D) and [Cu(CH₃ CN)_3.5 ][FAl{OC₆ F₁₀ (C₆ F₅ )}₃ ] (CuFAl, E)) affords seven unprecedented coordination compounds. Depending on the E₂ ligand complex, the counter anion of the copper salt and the stoichiometry, four dinuclear copper dimers and three trinuclear copper compounds are accessible. The latter complexes reveal first linear Cu₃ arrays linked by E₂ units (E=P, As) coordinated in an ?^2:1:1 coordination mode. All compounds were characterized by X-ray crystallography, NMR and IR spectroscopy, mass spectrometry and elemental analysis. To define the nature of the Cu???Cu???Cu interactions, DFT calculations were performed.

SUBMITTER: Schiller J

PROVIDER: S-EPMC7756472 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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Publications

Linking of CuI Units by Tetrahedral Mo2 E2 Complexes (E=P, As).

Schiller Jana J Schreiner Andrea A Seidl Michael M Balázs Gábor G Scheer Manfred M

Chemistry (Weinheim an der Bergstrasse, Germany) 20201008 64

The reaction of [Cp2 Mo2 (CO)4 (μ,η2:2 -E2 )] (A: E=P, B: E=As, Cp=C5 H5 ) with the WCA-containing CuI salts ([Cu(CH3 CN)4 ][Al{OC(CF3 )3 }4 ] (CuTEF, C), [Cu(CH3 CN)4 ][BF4 ] (D) and [Cu(CH3 CN)3.5 ][FAl{OC6 F10 (C6 F5 )}3 ] (CuFAl, E)) affords s ...[more]

PMID: 32614109

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Project description:The mechanisms of photoextrusion reactions are determined theoretically for the model system of six-coordinated M(CO)5(CS) (M = Cr, Mo, and W), using both CASSCF and MP2-CAS methods and the Def2-SVPD basis set. Three types of elimination reaction pathways (i.e., path I, path II, and path III for axial CO extrusion, equatorial CO extrusion, and CS ligand extrusion, respectively) are considered in this study. Theoretical findings show that the photoextrusion mechanism for Cr and Mo complexes proceeds as follows: M-S0-Rea + hν → M-S1-FC → M-CI → M-Pro + CO. This study shows that when the reactant, M(CO)5(CS) (M-S0-Rea), is photoirradiated by UV light, it is excited vertically to many low-lying singlet excited states. It then relaxes to the first singlet excited state from the Franck-Condon point (M-S1-FC). After passing through a conical intersection point (M-CI), this species eliminates a CO group to yield a five-coordinated product, M(CO)4(CS) (M-S0-Pro). However, for the W analogue, the photolysis mechanism is represented as W-S0-Rea + hν → W-T1-Min → W-T1-TS → W-T1/S0 → W-S0-Pro + CO. That is to say, when the reactant, W(CO)5(CS) (W-S0-Rea), absorbs UV light, it is excited to its several low-lying excited states by a vertical excitation. This species may then return to an intermediate at the first triplet excited state (W-T1-Min) by means of intersystem crossings or conical intersections. After passing through a triplet transition state (W-T1-TS) and a subsequent intersystem crossing (W-T1/S0), this molecule finally loses a CO ligand to produce a photoproduct at the ground singlet state (W-S0-Pro). In other words, conical intersections and intersystem crossings play a decisive role in these photoextrusion reactions for M(CO)5(CS). Theoretical evidence from a kinetic viewpoint strongly supports the theory that the photolysis of M(CO)5(CS) only produces CO-loss photoproducts rather than the CS-loss photoproduct. Theoretical analysis using the results of this study allows a good interpretation of the available experimental observations.

Project description:BackgroundDiacetyl-bis(N4-methylthiosemicarbazone), labeled with 64Cu (64Cu-ATSM) has been suggested as a promising tracer for imaging hypoxia. However, various controversial studies highlighted potential pitfalls that may disable its use as a selective hypoxic marker. They also highlighted that the results may be tumor location dependent. Here, we first analyzed uptake of Cu-ATSM and its less lipophilic counterpart Cu-Cl2 in the tumor over time in an orthotopic glioblastoma model. An in vitro study was also conducted to investigate the hypoxia-dependent copper uptake in tumor cells. We then further performed a comprehensive ex vivo study to compare 64Cu uptake to hypoxic markers, specific cellular reactions, and also transporter expression.MethodsμPET was performed 14 days (18F-FMISO), 15 days (64Cu-ATSM and 64Cu-Cl2), and 16 days (64Cu-ATSM and 64Cu-Cl2) after C6 cell inoculation. Thereafter, the brains were withdrawn for further autoradiography and immunohistochemistry. C6 cells were also grown in hypoxic workstation to analyze cellular uptake of Cu complexes in different oxygen levels.ResultsIn vivo results showed that Cu-ASTM and Cu-Cl2 accumulated in hypoxic areas of the tumors. Cu-ATSM also stained, to a lesser extent, non-hypoxic regions, such as regions of astrogliosis, with high expression of copper transporters and in particular DMT-1 and CTR1, and also characterized by the expression of elevated astrogliosis. In vitro results show that 64Cu-ATSM showed an increase in the uptake only in severe hypoxia at 0.5 and 0.2% of oxygen while for 64Cu-Cl2, the cell retention was significantly increased at 5% and 1% of oxygen with no significant rise at lower oxygen percentages.ConclusionIn the present study, we show that Cu-complexes undoubtedly accumulate in hypoxic areas of the tumors. This uptake may be the reflection of a direct dependency to a redox metabolism and also a reflection of hypoxic-induced overexpression of transporters. We also show that Cu-ATSM also stained non-hypoxic regions such as astrogliosis.

Dataset Information

Linking of Cu^I Units by Tetrahedral Mo₂ E₂ Complexes (E=P, As).

Publications

Linking of Cu<sup>I</sup> Units by Tetrahedral Mo<sub>2</sub> E<sub>2</sub> Complexes (E=P, As).

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