Studies of the supramolecular chemistry of iso-tellurazole N-oxides have been confined to non-polar media until now. To overcome that limitation, an iso-tellurazole N-oxide was derivatized with a primary alcohol group; the compound is soluble in polar solvents and stable in acidic to neutral aqueous media. Nickel (II) and iron (II) form macrocyclic complexes with six molecules of that isotellurazole N-oxide in a hitherto not-observed macrocyclic arrangement defined by CTe…O chalcogen bonds and κ6-O bound to the metal ion. This behaviour is in sharp contrast with the κn-Te (n = 1,2,4) complexes formed by soft metal ions.

The synthesis and characterization of novel N-heterocyclic carbene (NHC) stabilized dialanes Al2Mes4 as well as first investigations concerning the reactivity of these compounds are reported. The synthesis of these compounds proceeds via the Mesityl-substituted alanes (NHC)·AlHMes2 (NHC = IMeMe3, IiPrMe4) and iodo-alanes (NHC)·AlIMes2 (NHC = IMeMe5, IiPrMe6). Metallic reduction of 5 and 6 afforded the new NHC-stabilized dialanes (NHC)2·Al2Mes4 (NHC = IMeMe7, IiPrMe8). The NHC-ligated dialanes are thermally robust and storable synthons for the dialane Al2Mes4. First reactivity studies on (IMeMe)2·Al2Mes47 towards small molecules confirm this, as 7 shows controlled and selective reactions with several substrates. Reaction with CuCl leads to oxidation of the dialane and formation of (IMeMe)·AlClMes210, reactions with pyridine N-oxide and tBu-N=C=S, respectively, gave the chalcogenide-bridged dimers ((IMeMe)·AlMes2)2-μ-E (E= O 11, S 12), and reaction with acetylene afforded the dimetallaacetylide ((IMeMe)·AlMes2)2-μ-(C≡C) 13.

While many dye binding aptamers have been reported, most of them were for light-up aptamers that can significantly enhance the quantum yield of fluorophores. Sulforhodamine B (SRhB) was used as a target previously to select both DNA and RNA aptamers, and the DNA aptamer was a G-quadruplex that can bind to a number of rhodamine analogs. In addition, the previous selections were performed by immobilizing the target molecules. In this work, we used the library immobilization method to respectively select aptamers for SRhB and fluorescein. The SRhB aptamer has a non-G-quadruplex structure with a Kd of 1.0 µM measured from isothermal titration calorimetry. Upon titration of the aptamer, the fluorescence of SRhB increased 2.5-fold, and this aptamer does not require Mg2+ for binding. Rhodamine B has even tighter binding suggesting binding through the xanthene moiety of the dyes. No binding was detected for fluorescein. For the fluorescein selection, a dominant aptamer sequence with a Kd of 147 µM was obtained. This study provides two new aptamers for two important fluorophores that can be used to study aptamer-based separation, dye detection and catalysis. Comparison of these aptamers also provide insights into the effect of functional groups on aptamer binding.

The anion recognition and electrochemical anion sensing properties of halogen bonding (XB) tripodal zinc (II)-receptors strategically designed and constructed for tetrahedral anion guest binding are described. The XB tris(iodotriazole)-containing hosts exhibit high affinities and selectivities for inorganic phosphate over other more basic, mono-charged oxoanions such as acetate and the halides in a competitive CH3CN/ D2O 9:1 v/v aqueous solvent mixture. 1H NMR anion binding and electrochemical voltammetric anion sensing studies with redox-active ferrocene functionalised metallo-tripodal receptor analogues, reveal each of the XB tripods as superior anion complexants when compared to their tris(prototriazole)-containing, hydrogen bonding (HB) counterparts, not only exemplifying the halogen bond as a strong alternative interaction to the traditional hydrogen bond for molecular recognition but also providing rare evidence of the ability of XB receptors to preferentially bind the ‘harder’ phosphate oxoanion over the ‘softer’ and less hydrated halides in aqueous containing media.