Designer Ligands. Part 10.¹ Novel Nickel(Ii)-Selective Ligands for Use in the Construction of Molecularly Imprinted Polymers

Abstract

Novel, bidentate nickel(II)-selective ligands have been developed for use in the construction of molecularly imprinted polymers (MIPs), preliminary evaluation of which indicates high selectivity for nickel(II) over iron(III).

Designer ligands. Part 11. Electron-ionisation mass spectrometric studies of polydentate malonamide-derived ligands

“…Alkylation 5 of the sodium enolate of diethyl malonate 1 with selected alkyl halides (RX) afforded the alkylated derivatives 2b-j in yields ranging from 47 to 83%. 1 H and 13 C NMR analysis of these esters revealed the presence of both keto and enol tautomers in CDCl 3 solution, the former being dominant under these conditions. Treatment of diethyl malonate 1 and its C-alkylated dervatives 2b-j with ethanolamine 6 at room temperature (for periods of between 2 and 168 hours) gave the corresponding N,N'-bis(2-hydroxyethyl)malonamides 4a-j ( Table 1).…”

“…The latter fragment (m/z 228) also appears to be formed directly from the molecular ion and from the odd-electron species (m/z 258). The common fragmentations of the malonamides 4a, j-l (Scheme 4) appear to involve loss of a radical species R 1 • from the molecular ion I to give a resonance-stabilised cation II, which undergoes sequential fission to yield acylium cations of types III and IV. These fragmentation patterns were observed regardless of the nature of the substituents R 1 and R 2 .…”

Designer ligands: The search for metal ion selectivity

“…In the mixing (or pre-arrangement) step, solutions of the nickel(II) salts (the print species) with two equivalents of each of the bidentate ligands 25a-g (the functional monomers) in methanol (the porogenic solvent) were stirred overnight -the colour of the solutions typically changed from light-yellow to light-green. 32 MIPs were prepared using each of the seven ligands 25a-g and then subjected to preliminary evaluation of their relative extraction efficiencies, equilibration times, and mesh-size and counter-ion effects. 31 Residual nickel(II) and iron(III) concentrations following extraction were determined initially by atomic absorption spectroscopy.…”