%0 Journal Article
%T Electrochemical Behavior of Ni(II)-Salen at the Mercury Electrode
%A P¨¦rcio Augusto Mardini Farias
%A Margarida Bethlem Rodrigues Bastos
%J International Journal of Electrochemistry
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/257926
%X The complex Ni(II)-salen has been studied using cyclic and square-wave cathodic stripping voltammetry at the static mercury drop electrode in an aqueous media of phosphate and Hepes buffers (at pH 7.0). The resulting voltammograms consist of a totally irreversible one-electron transfer attributable to the coupling of Ni(II) salen/Ni(I) salen via an EC mechanism. The mean value for the transfer coefficient ¦Á in both supporting electrolytes was calculated as 0.35 ¡À 0.05. The amount of reactant adsorbed after 60£¿s of accumulation at £¿700£¿mV was calculated to be 2.8 ¡Á 10£¿8£¿mol¡¤cm£¿2. The detection limit for nickel determination was found to be 3.4 ¡Á 10£¿9£¿mol£¿L£¿1. 1. Introduction The effective clinical use of cis-diammine dichloro platinum(II) complex and other platinum complexes in the treatment of human cancer has stimulated studies in the interaction of DNA with different metal complexes. While some metal complexes possess potential antitumor activities, many others are persistent environmental hazards. The understanding of the precise nature of the interaction of different metal complexes with DNA is crucial to better predict their utilization for diverse purposes such as pharmacology, controlling genetic information, and the elucidation of protein-DNA contacts or gene therapy [1]. Several areas of chemistry have taken great interest in salen-type Schiff bases and their complexes with transition metals. This is mainly due to their biological activity [2, 3], optical [4, 5], catalytic [6¨C9], chromophoric [10], thermochromic [11], and photochromic [12] properties. In analytical chemistry, this class of compounds has been used to impregnate ion exchange resins for the study of Cu(II), Co(II), and Ni(II) complexes [13], in the fluorescent analysis of some amines [14] and amino acids [15] and in solvent extraction of Ga(II) and Fe(III) complexes [16]. Ni(II)-selective ion sensors of salen-type Schiff base chelates have also been developed [17]. Recently, it was found that some transition metal complexes, such as manganese [1, 18], nickel [19¨C23], iron [24], ruthenium [25], and copper [26], with ligands of the salen type can selectively modify DNA and RNA [27¨C29]. The oxidative and reductive chemistry of nickel(II) complexes with Schiff bases of salen type has been studied extensively in organic solvents with different coordinating strength [30¨C37]. In the present work, the electrochemical behavior of Ni(II)-salen (Figure 1) at a mercury electrode in an aqueous phosphate and Hepes buffers (pH 7.0) by cyclic and square-wave stripping voltammetry has been
%U http://www.hindawi.com/journals/ijelc/2013/257926/