A remarkable anion effect on the crystal packing of two analogous copper complexes from a thiophene-containing phenol-based ligand Iryna A. Koval a , Maila Sgobba a , Mieke Huisman a , Matthias Lu ¨ken b , Eric Saint-Aman c , Patrick Gamez a , Bernt Krebs b , Jan Reedijk a, * a Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands b Institut fu ¨ r Anorganische und Analytische Chemie der Westfa ¨ lischen Wilhelms-Universita ¨t Mu ¨ nster, Wilhelm-Klemm-Straße 8, 48149 Mu ¨ nster, Germany c Laboratoire d’Electrochimie Organique et de Photochimie Redox, UMR CNRS 5630, Universite ´ J. Fourier, B.P. 53, 38041 Grenoble Cedex, France Received 15 March 2006; accepted 10 April 2006 Available online 22 April 2006 Abstract The new asymmetric phenol-based N,O,S-ligand Hpy2th1as was prepared by the straightforward reductive amination of 3-{[bis(pyri- din-2-ylmethyl)amino]methyl}-2-hydroxybenzaldehyde with (thiophen-2-yl)methylamine. This potentially hexadentate ligand was used to coordinate to copper(II) chloride. Two dinuclear copper complexes were thus synthesised and fully characterized. Although the two coordination compounds exhibit identical complex cations, the crystal packings of both molecules significantly differ, which is most likely induced by the distinct, but geometrically related anions, namely tetrachlorocuprate(II) and perchlorate. Ó 2006 Elsevier B.V. All rights reserved. Keywords: Copper; N,S,O-ligand; Compartmental phenol-based ligand; Supramolecular interactions; Tetrachlorocuprate 1. Introduction Supramolecular assemblies result from a variety of intra- and inter-molecular interactions which may inter- play. In crystal engineering, synergistic effects between intermolecular non-covalent interactions are of great importance and must be considered as a single interrelated entity [1]. Among the different non-covalent interactions, H bonding is a key interaction in supramolecular chemistry [2], and particularly in the field of crystal engineering where it often involves the solvent of crystallization [3]. Since the past five years, we have been involved in the design of novel sulfur-containing dinucleating phenol- based ‘‘end-off’’ compartmental ligands to appraise the binding abilities of the thiophenyl ring [4,5], since it has been shown that the S-donor aromatic ring may act as semi-coordinating ligand [6]. Furthermore, it has recently been shown that many parameters influence the crystal packing, one of these being the nature of the anion [7], as detailed in the present study. An unsymmetrical compartmental ligand bearing a thio- phenyl group is herein reported together with two copper complexes. Although the two coordination compounds exhibit exactly the same cationic moiety, their crystal pac- kings are significantly different, clearly as a result of the presence of distinct anions which play an important role in the formation of different hydrogen bond networks. 2. Experimental 2.1. General All chemicals were commercially available and used with- out further purification. (Thiophen-2-yl)methylamine was purchased from Acros. Ligand field spectra of the solid-state compounds were recorded on a Perkin Elmer Lambda 900 UV/Vis/NIR spectrophotometer equipped with a Paragon 900 work station, using the diffuse reflectance technique 0020-1693/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.ica.2006.04.012 * Corresponding author. Tel.: +31 715274459; fax: +31 715274671. E-mail address: reedijk@chem.leidenuniv.nl (J. Reedijk). www.elsevier.com/locate/ica Inorganica Chimica Acta 359 (2006) 4071–4078