Well-Defined Triflylamide-Tethered Arene−Ru(Tsdpen) Complexes for Catalytic Asymmetric Hydrogenation of Ketones

Ito, Masato; Endo, Yoshinori; Ikariya, Takao

doi:10.1021/om800735z

Cited by 60 publications

(28 citation statements)

References 29 publications

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“…[16] The hydrogenolytic deactivation of [1H] + may be generally applicable to amido-based TH catalysts under acidic conditions. Protonation of the TsDPEN ligand would weaken the Ir-NTs bond.…”

Section: Resultsmentioning

confidence: 99%

Activation and Deactivation of Cp*Ir(TsDPEN) Hydrogenation Catalysts in Water

2009

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The addition of H3PO4 to Cp*Ir(TsDPEN‐H), where TsDPEN = H2NCHPhCHPhNTs–, is a simple method to obtain a water‐soluble hydrogenation catalyst capable of reducing aromatic ketones to their corresponding alcohols in aqueous solutions. Key to the reactivity is the low affinity of the coordinatively unsaturated [Cp*Ir(TsDPEN)]+ for H2PO4–. Catalyst degradation proceeds via the protonation of the tosylamido ligand, as was established by the crystallographic characterization of the tosylamine complex [Cp*Ir(NCMe)(HTsDPEN)]2+.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Resultsmentioning

confidence: 99%

Activation and Deactivation of Cp*Ir(TsDPEN) Hydrogenation Catalysts in Water

2009

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“…In general, higher percentages of open‐tether Ru II species are observed with increasing steric hindrance on the nitrogen atoms of the N , N ‐chelating diamine (Figure ). Strikingly, complex 9 (XY=tmen), which has the largest rate constant for the opening process of the series, showed the lowest percentage of open species at equilibrium, perhaps attributable to the lack of H‐bonding capability of tmen …”

Section: Resultsmentioning

confidence: 93%

“…Strikingly,c omplex 9 (XY = tmen), which hast he largestr ate constantf or the opening process of the series,s howedt he lowest percentage of open speciesa te quilibrium, perhaps attributable to the lack of H-bonding capability of tmen. [24] Ad ecreasei nt he concentration of DCl (0.01 m)r esulted in a modest extent of activation of the RuÀN tether bond (ca. 2-5 % of open-tether species at equilibrium).…”

Section: Activation Undera Cidicconditionsmentioning

confidence: 99%

Control of Reversible Activation Dynamics of [Ru{η⁶:κ¹‐C₆H₅(C₆H₄)NH₂}(XY)]ⁿ⁺ and the Effect of Chelating‐Ligand Variation

Martínez‐Peña

Pizarro

2017

Chemistry A European J

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The potential use of organoruthenium complexes as anticancer drugs is well known. Herein, a family of activatable tethered ruthenium(II) arene complexes of general formula [Ru{η :κ -C H (C H )NH }(XY)] (closed tether ring) bearing different chelating XY ligands (XY=aliphatic diamine, phenylenediamine, oxalato, bis(phosphino)ethane) is reported. The activation of these complexes (closed- to open-tether conversion) occurs in methanol and DMSO at different rates and to different reaction extents at equilibrium. Most importantly, Ru -complex activation (cleavage of the Ru-N bond) occurs in aqueous solution at high proton concentration (upon N protonation). The activation dynamics can be modulated by rational variation of the XY chelating ligand. The electron-donating capability and steric hindrance of XY have a direct impact on the reactivity of the Ru-N bond, and XY=N,N'-dimethyl-, N,N'-diethyl-, and N,N,N',N'-tetramethylethylenediamine afford complexes that are more prone to activation. Such activation in acidic media is fully reversible, and proton concentration also governs the deactivation rate, that is, tether-ring closure slows down with decreasing pH. Interaction of a closed-tether complex and its open-tether counterpart with 5'-guanosine monophosphate revealed selectivity of the active (open) complex towards interaction with nucleobases. This work presents ruthenium tether complexes as exceptional pH-dependent switches with potential applications in cancer research.

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“…[Ru(η 6 -1,1,1-trifluoro-N-phenethylmethanesulfonamide)Cl 2 ] 2 [27], [Ru(η 6 -1,1,1-trifluoro-N-(3phenylpropyl)methanesulfonamide)Cl 2 ] 2 [27], [Ru(η 6 -1,1,1-trifluoro-N-(4-phenylbutyl)methanesulfona mide)Cl 2 ] 2 [27], [Ru(η 6 -N-phenethylacetamide)Cl 2 ] 2 [28], [Ru(η 6 -N-phenethylmethanesulfonamide)Cl 2 ] 2 [15] and 2-(cyclohexa-1,4-dien-1-yl)ethan-1-amine [29] were synthesized as previously reported.…”

Section: Synthesismentioning

confidence: 99%

The Application of Reversible Intramolecular Sulfonamide Ligation to Modulate Reactivity in Organometallic Ruthenium(II) Diamine Complexes

et al. 2020

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Metallation of biomacromolecular species forms the basis for the anticancer activity of many metallodrugs. A major limitation of these compounds is that their reactivity is indiscriminate and can, in principle, occur in healthy tissue as well as cancerous tissue, potentially leading to side effects in vivo. Here we present pH-dependent intramolecular coordination of an arene-tethered sulfonamide functionality in organometallic ruthenium(II) ethylenediamine complexes as a route to controlling the coordination environment about the central metal atom. Through variation of the sulfonamide R group and the length of the tether linking it to the arene ligand the acidity of the sulfonamide NH group, and hence the pH-region over which regulation of metal coordination occurs, can be modulated. Intramolecular sulfonamide ligation controlled the reactivity of complex 4 within the physiologically relevant pH-region, rendering it more reactive towards 5 -GMP in mildly acidic pH-conditions typical of tumour tissue compared to the mildly alkaline pH-conditions typical of healthy tissue. However, the activation of 4 by ring-opening of the chelate was found to be a slow process relative to the timescale of typical cell culture assays and members of this series of complexes were found not to be cytotoxic towards the HT-29 cell line. These complexes provide the basis for the development of analogues of increased potency where intramolecular sulfonamide ligation regulates reactivity and therefore cytotoxicity in a pH-dependent, and potentially, tissue-dependent manner.Sadler et al. explored the reversible and pH-dependent equilibrium between ring-open and ring-closed forms of bis(aminophosphine) Pt(II) complexes [6,7].pH titrations with cis-[PtCl(Me 2 N(CH 2 ) 2 PPh 2 -N,P)(Me 2 N(CH 2 ) 2 PPh 2 -P)]Cl ( Figure 1A) yielded a pK a value of 6.9 and the equilibrium was also found to be dependent on Cl − concentration. cis-[PtCl(Me 2 N(CH 2 ) 2 PPh 2 -N,P)(Me 2 N(CH 2 ) 2 PPh 2 -P)]Cl was reported to be active against several cell lines, in conditions in which the open form of the complex would be present, but both cis-[PtCl(Me 2 N(CH 2 ) 2 PPh 2 -N,P)(Me 2 N(CH 2 ) 2 PPh 2 -P)]Cl and the ring closed form were found to react rapidly with 5 -GMP. This indicates the closed form of the complex is unable to regulate coordination of DNA to the metal center, although coordination of S-donor ligands to Pt(II) was prevented in the ring-closed form of the complex. A series of bis(O-alkyldithiocarbonato)platinum(II) complexes ( Figure 1B) were found to be more active at pH 6.8 versus 7.4 with average IC 50 (pH 7.0)/IC 50 (pH 6.8) ratios >2 found across six tumor cell lines for selected complexes [8]. The increase in activity of the complexes at acidic pH was attributed to increased ligand protonation and consequential destabilization of the complex, leading to increased reactivity. A bis(2-aminoethanolato-κ 2 N,O) platinum(II) complex ( Figure 1C) was also shown to exhibit increased reactivity toward 5 -GMP at pH 6.0 versus pH 7.4 [9], although r...

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Well-Defined Triflylamide-Tethered Arene−Ru(Tsdpen) Complexes for Catalytic Asymmetric Hydrogenation of Ketones

Cited by 60 publications

References 29 publications

Activation and Deactivation of Cp*Ir(TsDPEN) Hydrogenation Catalysts in Water

Activation and Deactivation of Cp*Ir(TsDPEN) Hydrogenation Catalysts in Water

Control of Reversible Activation Dynamics of [Ru{η⁶:κ¹‐C₆H₅(C₆H₄)NH₂}(XY)]ⁿ⁺ and the Effect of Chelating‐Ligand Variation

The Application of Reversible Intramolecular Sulfonamide Ligation to Modulate Reactivity in Organometallic Ruthenium(II) Diamine Complexes

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Well-Defined Triflylamide-Tethered Arene−Ru(Tsdpen) Complexes for Catalytic Asymmetric Hydrogenation of Ketones

Cited by 60 publications

References 29 publications

Activation and Deactivation of Cp*Ir(TsDPEN) Hydrogenation Catalysts in Water

Activation and Deactivation of Cp*Ir(TsDPEN) Hydrogenation Catalysts in Water

Control of Reversible Activation Dynamics of [Ru{η6:κ1‐C6H5(C6H4)NH2}(XY)]n+ and the Effect of Chelating‐Ligand Variation

The Application of Reversible Intramolecular Sulfonamide Ligation to Modulate Reactivity in Organometallic Ruthenium(II) Diamine Complexes

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Control of Reversible Activation Dynamics of [Ru{η⁶:κ¹‐C₆H₅(C₆H₄)NH₂}(XY)]ⁿ⁺ and the Effect of Chelating‐Ligand Variation