Note A phenyl-salicyliden-imine as a suitable ligand to build functional materials Archimede Rotondo a, * , Giuseppe Bruno a , Giovanna Brancatelli a , Francesco Nicolo ` a , Donatella Armentano b a Dipartimento di Chimica Inorganica, Analitica e Chimica Fisica, Universita ` di Messina, Salita Sperone 31, Vill. S. Agata, 98166 Messina, Italy b Dipartimento di Chimica, Universita ` della Calabria, Campus Arcavacata, via Bucci-87036, Cosenza, Italy Received 29 October 2007; received in revised form 29 January 2008; accepted 31 January 2008 Available online 7 February 2008 Abstract The synthesis and characterization of 1,4-dicarboxy-phenyl-2-salicyliden-imine (DPSI), a new multi-functional and tridentate ligand, is presented together with the crystal structure of its copper(II) complex. DPSI chemical groups result very attractive because of the straightforward crystal engineering applications, so that we believe this is the first among a wide gamma of materials with promising features and properties. Ó 2008 Elsevier B.V. All rights reserved. Keywords: Crystal engineering; Schiff-base; Structural properties; Inorganic complexes 1. Introduction The field of crystal engineering is primarily concerned with the ability to predictably synthesize supramolecular structures from well-designed building blocks [1]. To date, is still a big challenge the precise prediction of the structure of a molecular solid because crystal packing is driven by many weak non-covalent interactions [2] and even taking into account all the thermodynamic contributions to the stability, often experimental data show different arrange- ments driven by kinetically favoured processes [3]. To design specific architectures, suitable substrates should bear functional groups that are apt to develop predefined interactions (synthones [4]); for this purpose, often, planar (aromatic) molecules with carboxylic and/or aminic groups [5,6] were exploited as the building blocks (tectons [7]). In this field, our group was attracted by the structural features of the 1,4–dicarboxy-2-amino-benzene or 2-amino-there- phtalic acid (2a-TPT) [8]. Aromatic salicyliden-imines (PSI) are accustomed mole- cules (because of the simultaneous presence of a p-conju- gated system and different functional groups) to generate intermolecular or ligand-to-metal interactions; indeed many studies present important applications [9] and phar- macological activities [10] flanked by structural and theo- retical PSI reports [11,12]. Albeit PSI are readily obtained by a well-known condensation with salicylaldehyde (SA) (Scheme 1), to our knowledge the product coming from 2a-TPT: the 1,4-dicarboxy-phenyl-2-salycilyden-imine (H 2 DPSI) (Scheme 1) is still not known. Inorganic chemis- try, on the other side, provides useful tools in order to design new functional materials, especially by embedding customized bridging ligands within metal–organic frame- works (MOF) with the subsequent obtainment of coordi- nation polymers [13]. Metal centres often tune and enhance the macroscopic properties of ligands such as NLO, magnetic behaviour, and electric conductivity [14–16]. It is also demonstrated for PSI complexes [17–20]. On these bases here we present the synthesis of the new ligand H 2 DPSI together with the preparation and struc- tural resolution of its Cu(II) complex of the formula [Cu 2 (DPSI) 2 (2a-TPT)(H 2 O)(MeOH)]  4H 2 O (1). Albeit 0020-1693/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.ica.2008.01.040 * Corresponding author. Tel.: +39 090 6765729; fax: +39 090 393756. E-mail address: arotondo@unime.it (A. Rotondo). www.elsevier.com/locate/ica Available online at www.sciencedirect.com Inorganica Chimica Acta 362 (2009) 247–252