Two new bis(pyridine)-bis(amide)-based copper(II) coordination compounds for the electrochemical detection of trace Cr(VI) and efficient electrocatalytic oxygen evolution

Abstract Two new metal-organic compounds (MOCs) [Cu(L) 0.5 (3-nba) 2 ] ( 1 ) and [Cu(L)(2,5-tdc)] ( 2 ) have been hydrothermally synthesized by employing the ligand N,N′ -di(3-pyridyl)adipoamide (L) and two carboxylic acids (3-Hnba = 3-nitrobenzoic acid, 2,5-H 2 tdc = 2,5-thiophenedicarboxylic acid) as ligands. Compound 1 displays a metal-organic chain-like structure formed by the {Cu 2 (3-nba) 4 } double-paddle wheel units and the µ 2 -bridging L ligands. The adjacent polymeric chains form a supramolecular layered structure through hydrogen bonding. Compound 2 shows a 3D metal-organic polymeric framework derived from Cu-L layers and µ 2 -bridging 2,5-tdc ligands, which presents a 3,5-connected {4.6 2 }{4.6 6 .8 3 } topology. The electrochemical and electrocatalytic behavior of the two compounds has been studied in detail. Carbon paste working electrodes modified with compounds 1 and 2 can be used as highly selective sensors for detecting traces Cr(VI). Both electrodes show also electrocatalytic performance in oxygen evolution reactions (OERs).