Reported here is a face-capped Fe(ii) molecular tetrahedron, [Fe(4)L(4)](BF(4))(8), . Single crystal X-ray diffraction at 153 and 293 K suggest spin crossover (SCO) and variable temperature magnetic susceptibility measurements confirm displays thermally driven SCO behaviour in the solid state and in dilute acetone solution centred around 284-288 K.
Large amplitude molecular switches have been developed using oxonium ions as the novel switching mechanism. Macrocycles that contain a polyether ring that are preorganized and of optimum geometry such that strong, linear Low-Barrier Hydrogen Bonds (LBHB, 2.4 to 2.6 A in length) are formed between a protonated amide oxygen and a cyclic ether, that lend significant iminol character to the amide. Deprotonation yields a large conformational change between closed and open forms, mindful of a new hinged, latch-type mechanical proton switch. Numerous open and closed forms have been characterized by X-ray crystallography, and the intramolecular hydrogen bond that forms between the protonated amide oxygen and the cyclic polyether oxygen accounts for the stability of these new acids. The open form of the deprotonated adducts persist in solution as indicated by the magnitude of coupling constants and other Nuclear Overhauser Effect experiments. Different saturated and unsaturated solid acids have been characterized including products derived from acetonitrile, propionitrile, caprylonitrile, acrylonitrile and adiponitrile, and also by reaction with primary amides in the case of phenyl and norbornene derivatives. We have also demonstrated that metal cations can replace the proton in the switching mechanism, characteristic of nascent synthetic pores.
Tear down the wall: Ready methods for the construction of libraries of both α‐ and β‐aza‐C‐rhamnomimetics with high levels of diastereoselectivity have allowed the identification of inhibitors of rhamnosyl‐processing enzymes. These include the first examples of analogues of the Mycobacterium tuberculosis sugar L‐rhamnose that are inhibitors of mycobacterial biosynthetic pathways.
Sweet medicine: Glycosylated analogues of pramlintide, in which specific Asn residues bear extended N‐glycan structures, may be accessed by a combination of solid‐phase peptide synthesis and highly efficient enzymatic glycosylation (see scheme; ENGases=endo‐β‐N‐acetylglucosaminidases). Glycopeptides display both in vitro and in vivo activity as amylin receptor agonists and effect ‘smoothing’ of blood glucose.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.