Dibenzocyclamnickel(II) as Ionophore in PVC-Matrix for Ni 2+-Selective Sensor

Abstract

The tetramethyldibenzocyclam derivative, was synthesized and characterized and was used for fabrication of potentiometric sensor for Ni2+ metal ion. 5,7,8,14-tetramethyldibenzo[b,i]-1,4,8,11-tetrazacyclotetradecanenickel(II) chloride, ([Ni(Me4Bzo2[14]ane N4)]Cl 2) (II) was obtained in good yield as orange red salt by Fe/HCl reduction of the corresponding tetraazaannulene complex [Ni(Me 4Bzo2taa)], (I). Membrane having [Ni(Me 4Bzo2[14]aneN4)]Cl2 (II) as electroactive material, sodium tetraphenylborate (NaTPB) as an anion discriminator, dibutyl butylphosphonate (DBBP) as plasticizer in PVC matrix in the percentage ratio 5.0:2.5:200:200 (II:NaTPB:DBBP:PVC)(w/w) exhibits a linear response to Ni2+ in the concentration range 7.0×10 -6- 1.0×10-1M with a slope of 29.8±0.2 mV/decade of activity and a fast response time of 12s. The sensor works well in the pH range 2.0-7.6 and can be satisfactorily used in presence of 40% (v/v) methanol, ethanol or acetone. The sensor is highly selective for Ni2+ over a large number of mono-, bi-and trivalent cations. The sensor has been successfully used as indicator electrode in the potentiometric titration of Ni2+ against EDTA. These electrodes can be used to determine the concentration of Ni2+ in real samples. © 2002 by MDPI.