Anion recognition and sensing of ruthenium(ii) and cobalt(ii) sulfonamido complexes

Abstract

A series of artificial receptors, based on a sulfonamido system, have been designed and synthesized. The interaction of these receptors with biologically important anions was determined by UV-vis, (1)H NMR titration and electrochemical experiments. Results indicate that these receptors show high recognition abilities for fluoride (F(-)) or acetate (AcO(-)), moderate affinities for dihydrogen phosphate (H(2)PO(4)(-)) or hydroxyl (OH(-)) and almost no affinities for chloride (Cl(-)), bromide (Br(-)) or iodide (I(-)). (1)H NMR titration shows that the interaction between the receptors and anions depends on the hydrogen-bond formation. The Co(III)/Co(II) redox signals of receptor and disappear gradually when the fluoride or acetate anions are added. Moreover, visual color changes accompany guest binding, enabling this system to act as colorimetric anion sensors. The colorimetric properties of these sensors are ascribed to the hydrogen-bond formation and the colorimetric group quinoxaline.

Functionalized Quinoxaline for Chromogenic and Fluorogenic Anion Sensing

“…Shang et al. compared ruthenium(II) and cobalt(III) sulfonamide–quinoxaline complexes as electrochemical sensors (Figure ) . Spectrophotometric results indicate that 22‐Ru II ‐BP and 23‐Co III ‐BP have strong affinities for F − or AcO − , and moderate affinities for H 2 PO 4 − or OH − .…”

Chromogenic and fluorogenic chemosensors and reagents for anions. A comprehensive review of the year 2009

“…73 32 shows an intense absorption band at 340 nm that, upon addition of the anions AcO -and F -, decreases, whereas three new absorptions at 380, 475 and 500 nm were developed (change in colour from orange-red to red). A family of bishydrazide derivatives of isoindolines, compounds 36-39 ( Figure 12), was prepared and the anion binding properties investigated by UV-visible studied.…”

N,O-ditosylethanolamine as effective reagent for the synthesis of heterocyclic tertiary amine salts

“…15 It should be noted that N(2) has an almost planar geometry (sum of angles is 359.55 o ) similar to related neutral sulfonamides. 16 The cation has a gauche- The compound 3a is a colorless solid soluble in common organic solvents.…”