A reusable zigzag copper(II) coordination polymer with bio-essential constituents as a facile DNA scission agent Sanjib Das, C. Madhavaiah, Sandeep Verma * , Parimal K. Bharadwaj * Department of Chemistry, Indian Institute of Technology Kanpur, 208016, India Received 18 February 2005; accepted 1 April 2005 Available online 23 May 2005 Abstract A copper(II) coordination polymer has been synthesized in the form of an infinite zigzag chain where each metal is bonded to one glycine, two adenine, one nitrate anion and a water molecule giving a distorted octahedral coordination geometry with N 3 O 3 donor set. Each chain is hydrogen-bonded through C–HO and N–HO interactions on both sides leading to an overall polymeric structure. This compound not only shows facile chemical nuclease activity for pBR322 supercoiled DNA but also can be reused keeping its scission activity unchanged. Ó 2005 Elsevier B.V. All rights reserved. Keywords: Copper(II) complex; Coordination polymer; Plasmid DNA cleavage; Reusability; Intermolecular interactions 1. Introduction Designing of metal complexes for cleaving DNA is currently an area of considerable interest from chemical as well as biological standpoints and offers potential applications in the field of medicine in the post-genomic era. Transition metal complexes as an artificial nucleases are a matter of an extensive research due to their diverse structural features and reactivities [1]. Exploration of copper(II) complexes as chemical nucleases have seen an upsurge in recent years due to biologically accessible redox potential and high affinity toward nucleobases [2]. There are several reports in the literature on copper-in- duced DNA cleavage by using various exogenously added co-reactants such as hydrogen peroxide, peroxy- acids and thiols [3]. The best studied examples are mononuclear copper(II) complexes containing 1,10-phe- nanthroline and its derivatives since they are extensively used as a footprinting reagent for DNA, RNA, and important cellular processes [4]. But unfortunately very little attention is paid on coordination polynuclear com- plexes [5]. Modular synthesis of coordination polynu- clear complexes is a subject of considerable current interest [6–10] for potential application in opto-electron- ics, supramolecular storage, catalysis, magnetic materi- als and so on. These structures can be rapidly, accurately and efficiently built from relatively simple sub-units where metal ions, multi-dentate organic li- gands and coordinate bonding are the parameters for directing the self-assembly process. Of these, polynu- clear copper complexes are attracting attention because of their interesting magnetic properties and their rele- vance to the active centers of a number of metallo-pro- teins [11]. Adenine is an important nucleobase forming a large family of biological compounds. Recently, it has been found that the potential of adenine moieties ad- sorbed on inorganic surfaces to act as coding and recog- nition elements at the air–water interface [12]. Besides, copper complexes of amino acids are of continuing interest since they are simple model systems for the 0020-1693/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ica.2005.04.003 * Corresponding author. Tel.: +91 512 259 7304; fax: +91 512 259 7436. E-mail address: pkb@iitk.ac.in (P.K. Bharadwaj). www.elsevier.com/locate/ica Inorganica Chimica Acta 358 (2005) 3236–3240