Optically Activated Uptake and Release of Cu²⁺ or Ag⁺ Ions by or from a Photoisomerizable Monolayer-Modified Electrode

Abstract

Di-(N-butanoic acid-1,8-naphthalimide)-piperazine dithienylethene was covalently linked to a cysteamine monolayer associated with a Au surface to yield a photoisomerizable monolayer composed of the open or closed dithienylcyclopentene isomers (3a or 3b), respectively. Electrochemical and XPS analyses reveal that the association of metal ions to the monolayer is controlled by its photoisomerization state. We find that Cu(2+) ions reveal a high affinity for the open (3a) monolayer state, K(a) = 4.6 × 10(5) M(-1), whereas the closed monolayer state (3b) exhibits a substantially lower binding affinity for Cu(2+), K(a) = 4.1 × 10(4) M(-1). Similarly, Ag(+) ions bind strongly to the 3a monolayer state but lack binding affinity for the 3b state. The reversible photoinduced binding and dissociation of the metal ions (Cu(2+) or Ag(+)) with respect to the photoisomerizable monolayer are demonstrated, and the systems may be used for the photochemically controlled uptake and release of polluting ions. Furthermore, we demonstrate that the photoinduced reversible binding and dissociation of the metal ions to and from the photoisomerizable electrode control the wettability properties of the surface.

Modified Electrodes and Electrochemical Systems Switchable by Light Signals

“…Another diarylethene derivative (di‐( N ‐butanoic acid‐1,8‐naphthalimide)‐piperazine dithienylethene) was covalently linked to a cysteamine monolayer associated with a Au surface to yield a photoisomerizable monolayer reversibly switchable between open‐ring and closed‐ring isomeric states , Figure . An interesting phenomenon was found for the switchable monolayer – association of metal ions (particularly Cu 2+ and Ag + ) to the monolayer was controlled by its photoisomerization state.…”

“…The processes of the uptake and release of the Ag + cations can be repeated reversibly by applying optical signals with different wavelength, Figure B, inset. Similar results were obtained for the complex formation with Cu 2+ cations . The micro‐variations in the molecular structure corresponding to the metal‐complex formation‐dissociation resulted in a macro‐effect at the electrode surface changing its wettability.…”

“…The micro‐variations in the molecular structure corresponding to the metal‐complex formation‐dissociation resulted in a macro‐effect at the electrode surface changing its wettability. The contact angle measured for the monolayer in the open‐ring form with the included Ag + cations was smaller, thus demonstrating more hydrophilic surface, than the contact angle measured for the closed‐ring form repealing Ag + cations, thus resulting in more hydrophobic interface , Figure C.…”

Intracellular pH sensing and targeted imaging of lysosome by a galactosyl naphthalimide-piperazine probe

“…Since the piperazine moiety is a commonly used chelating group [22,23], competition experiments were carried out in different pH solutions (acidic/neutral/basic) with metal ions that might interact with piperazine (Figs. S2eS4).…”

Fluorescent “turn-on” detecting CN− by nucleophilic addition induced Schiff-base hydrolysis

“…Plenty of chemosensor systems for cyanide anion detection reported to date are based on the mechanism of coordination [14][15][16][17][18][19], hydrogen-bonding interaction [20][21][22][23][24], nucleophilic addition reaction [25][26][27] and so on [28][29][30][31][32][33]. There are defects more or less among these cyanide sensors, for example, the sensors based on hydrogen-bonding interaction is often interfered by fluoride ions or acetic anions or other alkaline anions.…”