GO composite encompassing a tetraruthenated cobalt porphyrin-Ni coordination polymer and its behavior as isoniazid BIA sensor

A new cobalt(III) tetrapyridylporphyrin species (CoTPyP) coordinated to four ruthenium dicarboxybipyridine complexes, [Ru(H(2)dcbpy)(2)Cl](+) was synthesized and successfully deposited onto graphene oxide (GO) sheets by forming in situ a coordination polymer with nickel(II) ions, [CoTRP(dcbpy)(2)]-Ni. Because of the high negative charge of the [CoTRP(dcbpy)(2)](11-) species, such strategy helped overcoming the electrostatic repulsion with the carboxylate groups on the GO surface, allowing an effective binding through the available Ni(II) sites. In this way, a stable layered composite material was generated, and its characterization performed by means of spectroscopic, XRD and confocal Raman techniques. The material preserves the characteristics of the supramolecular tetraruthenated cobalt porphyrin species, and exhibits an unusual electrocatalytic activity in the oxidation of isoniazid, performing at low potentials in aqueous solution (0.10 V vs Ag/AgCl) and pH 7. The GC electrodes modified with this material were used for isoniazid analysis with the BIA assay, revealing an interesting amperometric sensor capable of working under very mild conditions, with a detection limit of 3.5 mu M. (C) 2019 Elsevier Ltd. All rights reserved.