Binuclear Cu2+ complex mediated discrimination between L-glutamate and L-aspartate in water.

TLDR: L-glutamate and L-aspartate selectivity is achieved by the action of two Cu2+ metal ions rightly disposed in a cyclophane-type macrocyclic framework.

About: This article is published in Chemical Communications.The article was published on 2005-06-13 and is currently open access. It has received 43 citations till now.

Figures

Fig. 2 SQWVs{ at a GCE modified by a deposit obtained via evaporation of 50 mL of a 2.0 6 1023 mol dm23 CuSO4?5H2O plus 1.0 6 1023 mol dm23 L?6HBr solution at pH 6.5 immersed into a) 0.15 mol dm23 NaClO4; b) idem plus 2.0 6 10 23 mol dm23 aspartic acid; c) idem plus 2.0 6 1023 mol dm23 glutamic acid, all at pH 7.5. Potential step increment 4 mV; square wave amplitude 25 mV; frequency 5 Hz.

Table 1 400 MHz 1H NMR hyperfine-shifted resonances in D2O at 40 uC and pH 5 6.5 for Cu2L and for Cu2L–Glu and Cu2L–Asp complexes, determined for 1:2 molar ratios

Fig. 1 Plot of the percentages of complexed glutamate and aspartate by L as free receptor and as Cu2+ complex.

Frequently asked questions

Q1. What are the contributions in this paper?

In this communication the authors offer means by which L-glutamate and L-aspartate discrimination can be achieved by the action of metal ions rightly disposed in a macrocyclic framework. Additionally, the amino and ammonium groups that L has at this pH could contribute to the binding of anions as hydrogen bond donors and/or acceptors while the pyridine aromatic moiety might provide p–ammonium interactions. A potentiometric study performed in 0. 15 mol dm NaClO4 shows that in the pH range 2–11, L forms adduct species [ HxLA ] ( x 2 2 ) with L-glutamate and L-aspartate, with x varying from 4 to 8. In order to check these conclusions by independent techniques the authors have performed paramagnetic H NMR measurements and electrochemical studies.