Bisferrocenyl-functionalized pseudopeptides: access to separated ionic and electronic contributions for electrochemical anion sensing
Pseudopeptidic receptors containing ferrocene fragments have been prepared and their response to a series of anions was measured by a voltammetry of microparticles methodology. Such water-insoluble compounds yield anion-assisted reversible solid-state oxidations differing in their open-circuit potential and their midpeak potential recorded in cyclic voltammetric measurements. The difference between those potentials provides the individual thermodynamic contributions of electron and proton transfer, revealing that the mechanism of an ion-sensitive electrode can differ in potentiometry and voltammetry. The studied receptors are potentially interesting for potentiometric sensing, showing relat…
Azonia spiro polyaza macrocycles containing biphenyl subunits as anion and cation receptors
Abstract The reaction of N-Boc triprotected cyclam with bis(chloromethyl)biphenyl followed by the corresponding deprotection of the nitrogen atoms allows the preparation of receptor 3 containing an azonia spiro subunit. This receptor shows slightly increased basicity than cyclam, in particular for the formation of the appropriate triply charged species as a consequence of the reduced capacity of the structure present in 3 to stabilize the species with lower protonation degrees through the formation of intramolecular hydrogen bonds. The properties of 3 as a receptor for Cu2+ and Zn2+ and the anions derived from PO 4 3 − ( Pi ) , P 2 O 7 4 − ( PPi ) , P 3 O 10 5 − ( TPP ) and ATP have been st…
Damming an electronic energy reservoir: ion-regulated electronic energy shuttling in a [2]rotaxane
We demonstrate the first example of bidirectional reversible electronic energy transfer (REET) between the mechanically bonded components of a rotaxane. Our prototypical system was designed such that photoexcitation of a chromophore in the axle results in temporary storage of electronic energy in a quasi-isoenergetic “reservoir” chromophore in the macrocycle. Over time, the emissive state of the axle is repopulated from this reservoir, resulting in long-lived, delayed luminescence. Importantly, we show that cation binding in the cavity formed by the mechanical bond perturbs the axle chromophore energy levels, modulating the REET process, and ultimately providing a luminescence read-out of c…