Aqua{4,4 00 0 -dimethoxy-2,2 00 0 -[pyridine-2,3-diylbis(nitrilomethanylylidene)]-diphenolato}copper(II)

Abstract

The title compound is one of the targeted materials to elaborate modified electrodes in order to use them in heterogeneous electrocatalysis. Therefore, this work is a continuation of investigations where 2,3-diaminophenol and 2,3-diamino-pyridine were involved (Ourari et al., 2006; Ouari et al., 2010; Ourari, Ouari et al., 2008). The resulting ligands or complexes may be functionalized by etherification (Vyas & Shah, 1963) or quaternization (Kataoka et al., 1979) reactions using N-(3-bromopropyl)pyrrole. These materials are mainly applied in catalysis, electrocatalysis and sensors (Ourari, Baameur et al., 2008; Coche-Guerente et al., 1995). The synthesis of new salicylaldehyde derivatives containing electropolymerizable units can be considered as the main source of functionalized π-conjugated conducting polymers as those of poly(pyrrole), poly(thiophene) and poly(aniline) (Huo et al., 1999; Khedkar & Radhakrishnan, 1997; Guo & Wong, 1999). We report here the synthesis of the title compound, [Cu(C21H17N3O4)(H2O)], (I) and its crystal structure. The molecular geometry of (I), and the atomic numbering used, is illustrated in Fig. 1. The asymmetric unit of (I) consists of one-half of the molecule, with the other half generated by a crystallographic mirror plane. Due to this symmetry the N2 and C10 atoms of the pyridine ring are equally disordered. The Cu II atom is five-coordinate in a distorted square pyramidal geometry by the O atoms of two 5-methoxysalicylidene groups, the imine N atoms and one molecule of water in the apical position. The bond lengths of the coordination sphere range from 1.9126 (14) to 2.416 (3) Å for Cu—O distances and is 1.9561 (16) Å for the Cu—N distance. The crystal packing in (I) can be described by alterning layers along [001] (Fig. 2). There are one intramolecular C—H···Nand two intermolecular C—H···O and O— H···O hydrogen bonding interactions in this packing (Fig. 3), which is further stabilized by C—H···πinteractions (Table 2) and π–πstacking (shortest centroid-to-centroid distance 3.799 (8); interplanar distance of 3.469 (2) Å).