Recyclable chemosensor for oxalate based on bimetallic complexes of a dinucleating bis(iminopyridine) ligand

Abstract

Herein we describe bimetallic di-nickel and di-copper complexes [Ni2(L)Br4] (1) and [Cu2(L)Br4(NCMe)2] (2) (L = (1E,1'E)-N,N'-(1,4-phenylenebis(methylene))bis(1-(6-(2,4,6-triisopropylphenyl)pyridin-2-yl)methanimine)) that bind oxalate intramolecularly to form [Ni2(L)Br2(C2O4)(NCMe)] (3) and [Cu2(L)Br2(C2O4)] (4). For the di-nickel complex 1, oxalate incorporation is accompanied by a significant colour change, from red-pink (1) to deep green (3). Mass spectrometric experiments demonstrate that the compound 1 is selective for oxalate versus related mono- and di-carboxylates tested. Oxalate can be released by the addition of slight excess of calcium bromide that forms insoluble calcium oxalate and restores the original Ni2(L)Br4 species. The product of the oxalate release was crystallized as [Ni2(L)Br4]·CaBr2(THF)4 species.

Electrocatalytic Reduction of CO2by Group 6 M(CO)6Species without “Non-Innocent” Ligands

“…Tetrabutylammonium oxalate was independently synthesized, and the 13 C­{ 1 H} NMR spectrum of the synthesized oxalate was used to confirm that oxalate was not present in any of the bulk electrolyses (Figures S20 and S21). When water (0.98 M) was included in the electrochemical cell, the bulk electrolysis current was decreased compared to that of the anhydrous reactions, consistent with the cyclic voltammetry experiments. When the headspace was analyzed by gas chromatography, carbon monoxide was observed at low faradaic efficiencies (35%), and hydrogen was also observed (47% faradaic efficiency).…”

“…Calibration curves for carbon monoxide and hydrogen were created by injecting known quantities of CO or H 2 into the electrochemical cell and then sampling the headspace (see Figures S22 and S23 of the Supporting Information). Tetrabutylammonium oxalate was synthesized as described in literature reports, and spectral data matched literature values. , …”

Cu2+, Zn2+, and Ni2+ Complexes of C2-Symmetric Pseudopeptides with an Aromatic Central Spacer

“…Again, the slow kinetics associated with Ni 2+ precluded an appropriate study of the corresponding complexes. The ESI-MS technique allows the detection in a solution of species at low concentration, and this makes it attractive to analyze complexation processes . This confirmed the formation of deprotonated complex species even at acidic pH regions.…”

Molecular Recognition of Biologically Relevant Anions with an Expanded Dinuclear Copper(II) Complex: An Efficient Sensor for Oxalate Anion in Aqueous Solution

“…[27][28] Using a supramolecular approach, there has been an immense interest in developing efficient chemical sensors for oxalate by colorimetric and fluorescence methods. [29][30][31][32][33][34][35][36][37][38][39][40][41] Previous studies demonstrated that the complexes of certain metal ions including zinc, [32][33] copper, [34][35][36][37][38][39] nickel, [40][41] and calcium [42] can be used as suitable chemosensors for detecting an oxalate anion in solution.…”