Lariat Ether Carboxylic Acids, O-Benzylhydroxamates and Hydroxamic Acids with Fluorinated Substituents: Synthesis, Metal Ion Complexation and Solubility in Supercritical Carbon Dioxide

Synthesis of lariat ether carboxylic acids based on dibenzo‐16‐crown‐5

“…Lariat ether carboxylic acids 9-11 (Table 1) with lipophilic groups at both the geminal position and on the side arm were prepared by reaction of the appropriate lariat ether alcohol and sodium or potassium hydride in tetrahydrofuran and the appropriate 2-bromocarboxylic acid as shown in Scheme 2. The sym-(R)(hydroxy)dibenzo-16-crown-5 precursors were prepared by reaction of [9] and the appropriate Grignard reagent [9,19,21,27]. In addition to reducing ligand loss from the organic phase during extraction of metal ions from aqueous solutions, the geminal substituent preorganizes the metal ion binding site by orienting the carboxylic acid group over the crown ether cavity [36].…”

“…These ligands have been found to be effective chelating agents for alkali and alkaline earth metal cations and trivalent lanthanide ions . In addition to their use as metal ion complexing agents, lariat ether carboxylic acids are important starting materials for the synthesis of lariat ethers with pendant alcohol [26,27], amide [26,28], ester [29], hydroxamate [19,21], and N-(X)sulfonyl carboxamide [30,31] groups, as well as bis(crown ether)s and macrotricyclic polyether compounds [26].…”

Synthesis of cobalt(II) complexes with p-tert-butylcalix[4]arene-supported dihydroxamic acids

“…7 Macrocyclic compound-tethered hydroxamic acid has been also reported. [8][9][10] Previously, we reported the dioxygen affinities of cobalt(II) hydroxamates and biomimetic catalytic oxidation performance of transition-metal hydroxamates. 11,12 In order to investigate the effects of calixarenes binding hydroxamic acid on some important performance of dihydroxamic acid, namely, ability for complexation with bivalent transition-metal ions and the dioxygen affinities of cobalt complexes, we designed and synthesised new p-tert-butylcalix [4]arene supported dihydroxamic acids 5a-5d (H 2 L 1 -H 2 L 4 ) (Fig.…”

Synthesis and Ionophoric Properties of Crown Ether Capped with a Convergent Hydroxamic Acid Function

“…Furthermore, as is well known, the hydroxamate function in the prepared compound can act as a counter ion in addition to the ligating site for the guest metal ions, that is definitely favorable for the action as an efficient ionophore. 16,17 The ionophoric properties of prepared compounds were investigated by the solvent extraction and transport experiments. To have a general idea about the ionophoric properties of 3, a preliminary solvent extraction experiment of metal ions from aqueous phase (buffered at pH 6 with HOAc/NaOAc) into chloroform solution was performed.…”