- Synthesis of functionalized hexadentate iminopyridine FeII complexes - Toward anion-dependent spin switching in polar media
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We report the syntheses and characterizations of low-spin FeII complexes of hexadentate ligands poised for aniontriggered spin-state switching in polar solutions: [Fe(L5-OH)]- (BF4)2 (1) and [Fe(L5-ONHtBu)](BF4)2 (3), in which L5-OH and L5-ONHtBu are tripodal iminopyridine ligands that contain methanolic or tert-butylamide functional groups, respectively, bound meta to the pyridyl N donor atom. Solid-state evidence for strong hydrogen bonding between Cl- anions and all three amide functional groups in [Fe(L5-ONHtBu)]2+ is provided by the crystal structure of {[Fe(L5-ONHtBu)]∪Cl} 2- [FeCl4] (2). In ambient-temperature acetonitrile solutions of 1 and 3, chloride ion titrations produce marked changes in the 1H NMR spectra, including large downfield shifts for the amide NH and hydroxy OH resonances, which indicates strong anion binding events. Interestingly, for amide-containing 3, we observe small changes in magnetic susceptibility as (nBu4N)Cl is added, which suggests that spin-state control by anion-cation interactions may be accessible for related compounds with weaker ligand fields.
- McDaniel, Ashley M.,Klug, Christina M.,Shores, Matthew P.
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- Development of Gene-Targeted Polypyridyl Triplex-Forming Oligonucleotide Hybrids
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In the field of nucleic acid therapy there is major interest in the development of libraries of DNA-reactive small molecules which are tethered to vectors that recognize and bind specific genes. This approach mimics enzymatic gene editors, such as ZFNs, TALENs and CRISPR-Cas, but overcomes the limitations imposed by the delivery of a large protein endonuclease which is required for DNA cleavage. Here, we introduce a chemistry-based DNA-cleavage system comprising an artificial metallo-nuclease (AMN) that oxidatively cuts DNA, and a triplex-forming oligonucleotide (TFO) that sequence-specifically recognises duplex DNA. The AMN-TFO hybrids coordinate CuII ions to form chimeric catalytic complexes that are programmable – based on the TFO sequence employed – to bind and cut specific DNA sequences. Use of the alkyne-azide cycloaddition click reaction allows scalable and high-throughput generation of hybrid libraries that can be tuned for specific reactivity and gene-of-interest knockout. As a first approach, we demonstrate targeted cleavage of purine-rich sequences, optimisation of the hybrid system to enhance stability, and discrimination between target and off-target sequences. Our results highlight the potential of this approach where the cutting unit, which mimics the endonuclease cleavage machinery, is directly bound to a TFO guide by click chemistry.
- Zuin Fantoni, Nicolò,McGorman, Bríonna,Molphy, Zara,Singleton, Daniel,Walsh, Sarah,El-Sagheer, Afaf H.,McKee, Vickie,Brown, Tom,Kellett, Andrew
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p. 3563 - 3574
(2020/10/02)
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- New Water-Soluble Copper(II) Complexes with Morpholine-Thiosemicarbazone Hybrids: Insights into the Anticancer and Antibacterial Mode of Action
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Six morpholine-(iso)thiosemicarbazone hybrids HL1-HL6 and their Cu(II) complexes with good-to-moderate solubility and stability in water were synthesized and characterized. Cu(II) complexes [Cu(L1-6)Cl] (1-6) formed weak dimeric associates in the solid state, which did not remain intact in solution as evidenced by ESI-MS. The lead proligands and Cu(II) complexes displayed higher antiproliferative activity in cancer cells than triapine. In addition, complexes 2-5 were found to specifically inhibit the growth of Gram-positive bacteria Staphylococcus aureus with MIC50 values at 2-5 μg/mL. Insights into the processes controlling intracellular accumulation and mechanism of action were investigated for 2 and 5, including the role of ribonucleotide reductase (RNR) inhibition, endoplasmic reticulum stress induction, and regulation of other cancer signaling pathways. Their ability to moderately inhibit R2 RNR protein in the presence of dithiothreitol is likely related to Fe chelating properties of the proligands liberated upon reduction.
- Ohui, Kateryna,Afanasenko, Eleonora,Bacher, Felix,Ting, Rachel Lim Xue,Zafar, Ayesha,Blanco-Cabra, Núria,Torrents, Eduard,D?m?t?r, Orsolya,May, Nóra V.,Darvasiova, Denisa,Enyedy, éva A.,Popovi?-Bijeli?, Ana,Reynisson, Jóhannes,Rapta, Peter,Babak, Maria V.,Pastorin, Giorgia,Arion, Vladimir B.
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p. 512 - 530
(2019/01/04)
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- A Ca2+-, Mg2+-, and Zn2+-Based Dendritic Contractile Nanodevice with Two pH-Dependent Motional Functions
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A contractile dendritic motional device is reported where metal ions with biological importance - Ca2+ (the main regulatory and signaling species of the natural muscles), Mg2+, and Zn2+ - initiate two kinds of motional functions. The first motional function is the metal-ion-induced contraction of a linear strand into a Z-shaped dinuclear complex, and the second one is the change of the height of Z-shaped complexes via transmetalation. By means of the pH-dependent counterligand tren, the two motional features of the machine can depend on alternate additions of acid and base. An optical response is associated with the conversion of the linear form (which is yellow) into the metalated Z-shaped one (which is red).
- Stadler, Adrian-Mihail,Karmazin, Lydia,Bailly, Corinne
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supporting information
p. 14570 - 14574
(2016/01/25)
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- Aromatic Retinoic Acid Analogues. 2. Synthesis and Pharmacological Activity
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Aromatic analogues of (E)-1-(4-carboxyphenyl)-2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)butadiene (1b) and its ethyl ester (1a) were synthesized as potential chemopreventive agents for the treatment of epithelial cancer and such skin diseases as psoriasis and cystic acne.The phenyl ring of 1 was replaced by 2-fluorophenyl, 2-methoxyphenyl, thienyl, furanyl, and pyridyl groups.The 1-fluorobutadiene analogue of 1 was also synthesized.With exception for the furanyl analogue, these compounds demonstrated good activity in reversing keratinization in hamster tracheal organ culture and in inhibiting the induction of ornithine decarboxylase in mouse epidermis by a tumor promoter.
- Dawson, Marcia I.,Chan, Rebecca,Hobbs, Peter D.,Chao, Wan-ru,Schiff, Leonard J.
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p. 1282 - 1293
(2007/10/02)
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- Mercaptoalkylpyridine disulfides
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Mercaptoalkylpyridines carrying an ethenyl or ethynyl substituent are prepared from known pyridine compounds, principally pyridoxine, by known chemical procedures, and are useful in the treatment of rheumatoid arthritis and related inflammatory diseases.
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