The helicates--chiral assemblies of two or more metal atoms linked by short or relatively rigid multidentate organic ligands--may be regarded as non-peptide mimetics of α-helices because they are of comparable size and have shown some relevant biological activity. Unfortunately, these beautiful helical compounds have remained difficult to use in the medicinal arena because they contain mixtures of isomers, cannot be optimized for specific purposes, are insoluble, or are too difficult to synthesize. Instead, we have now prepared thermodynamically stable single enantiomers of monometallic units connected by organic linkers. Our highly adaptable self-assembly approach enables the rapid preparation of ranges of water-stable, helicate-like compounds with high stereochemical purity. One such iron(II) 'flexicate' system exhibits specific interactions with DNA, promising antimicrobial activity against a Gram-positive bacterium (methicillin-resistant Staphylococcus aureus, MRSA252), but also, unusually, a Gram-negative bacterium (Escherichia coli, MC4100), as well as low toxicity towards a non-mammalian model organism (Caenorhabditis elegans).

No abstract

Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work of researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-forprofit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/ja502789eThe version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. ABSTRACT: Stereochemistry is a very important issue for pharmaceutical industry and can determine drug efficacy. Design and synthesis of small molecules, especially chiral molecules, which selectively target and inhibit amyloid (Aβ) aggregation represent valid therapeutic strategies for treatment of Alzheimer's disease (AD). Herein we report that two triple-helical dinuclear metallo-supramolecular complexes can act as a novel class of chiral amyloid-β inhibitors. Through targeting α/β-discordant stretches at the early steps of aggregation, these metal complexes can enantioselectively inhibit Aβ aggregation, which are demonstrated using fluorescent living cell-based screening and multiple biophysical and biochemical approaches. To the best of our knowledge, there is no report to show that a chiral compound can enantioselectively inhibit Aβ aggregation. Intriguingly, as a promising candidate for AD treatment, the chiral metal complex can cross the blood-brain barrier (BBB) and have SOD activity. Previous studies have demonstrated that chiral discrimination between enantiomers is extremely important, as stereopure drugs can often reduce the total dose of drug given and minimize any toxicity resulting from the inactive enantiomer. And this is also a critical factor which should be carefully considered in AD treatment. Our work provides new insights into chiral inhibition of Aβ aggregation and opens a new avenue for design and screening of chiral agents as Aβ inhibitors against AD.

Optically pure, single diastereomer fac-tris(diimine) complexes of Fe(II) are available from a remarkably facile one-pot procedure using a range of readily available (R)-2-phenylglycinol derivatives.