The chiral Zn(II)–Na(I) coordination polymer: Synthesis, crystal structure, thermal and optical properties Fatma Yuksel a,b , Yurii Chumakov a,c , Dominique Luneau a, * a Université Claude Bernard Lyon1, Laboratoire des Multimatériaux et Interfaces (UMR 5615), Campus de La Doua, 69622 Villeurbanne, France b Gebze Institute of Technology, Department of Chemistry, P.O. Box 141, Gebze 41400, Turkey c Institute of Applied Physics of Academy of Sciences of Moldova, Academy street, 5, MD-2028 Chisinau, Republic of Moldova article info Article history: Received 23 November 2007 Accepted 17 March 2008 Available online 25 March 2008 Keywords: Coordination polymer NLO Zn(II) complex Chiral complex Crystal engineering abstract The chiral Zn(II)–Na(I) coordination polymer with formula [NaZn(acac) 2 (AcO)(EtOH)] (1) has been syn- thesized, and characterized by 1 H NMR and FT-IR spectra, elemental, X-ray, and thermogravimetric anal- ysis (TGA). X-ray crystallographic study revealed that 1 crystallizes in the non-centrosymmetric space groups P2 1 2 1 2 1 and exhibits a one-dimensional polymer chain. Linear optical properties were investi- gated by UV/Vis spectrophotometer techniques. Kurtz–Perry powder second-harmonic-generation (SHG) test confirms the non-linear optical (NLO) property of the grown crystal. Ó 2008 Elsevier B.V. All rights reserved. The field of crystal engineering has rapidly developed to pro- duce new materials with interesting structural features and poten- tial applications, and is also one of the most active branches in current coordination chemistry [1–7]. By self-assembly of organic ligands and metal ions under appropriate conditions, a variety of novel metallo supramolecular architectures, such as coordination polymers and host-guest compounds, have been achieved so far [1–7]. The most important goal in this area is to synthesis func- tional materials with specific properties [8,9]. Chiral materials deserve a lot of investigations because of their importance in chemistry, biochemistry, pharmaceutics, and phys- ics (NLO, piezoelectricity) [10–13]. In this field chiral coordination complexes attracts intense interests due to their potential applica- tions in asymmetric catalysis [14,15], enantioselective separation [15,16] and optical activity [17–20], magnetic materials [21–26]. Generally, the chiral coordination complexes are synthesized from chiral ligands [18–20]. Another effective approach is to use achiral ligands and chiral templates to induce the chirality [17,27]. One of our interests lies in the synthesis and studies of chiral coordination compounds that may have magnetic or 2nd order non-linear optical properties [20,23–25]. For the second-har- monic-generation the interesting metal ions are Zn(II), Cd(II) and Hg(II) because of the lack of d–d transitions [20,28–32]. Among them the Zn(II) compounds generally exhibit the largest hyperpo- larizability [31,32]. Thus it was previously reported that square-pyramidal coordi- nation compounds, L Zn(acac) 2 , have a high probability to form non-centrosymmetric crystals [33]. Later Anthony and Radhakrishnan have presented the screw shaped asymmetric L Zn(acac) 2 crystals which formed in perfect assembly by self- poling [34]. Afterwards Quin and co-workers tried to extend conju- gation length of L but they obtained L Zn(acac) 2 crystallizing in centrosymmetric space groups [35,36]. They concluded that the screw shape of the molecule can not guarantee the formation of non-centrosymmetric crystals and that the ratio between the length and width in the screw has to be considered [37]. We present here in the synthesis, crystal structure, thermal and optical properties of a Zn(II)–Na(I) coordination polymer with formula [NaZn(acac) 2 (AcO)(EtOH)] (1). Complex 1 was obtained by the reaction of Zn(OAc) 2 .2H 2 O and acetyl acetone (acacH) with NaHCO 3 in ethanol as summarized in Scheme 1 [38]. The novel compound has been characterized by 1 H NMR and FT-IR spectra, elemental, X-ray, and thermogravimetric analysis (TGA) [39,40]. The use of NaCO 3 or sodium acetate instead of NaHCO 3 also gave the same product. The single crystal X-ray analysis revealed that complex 1 crys- tallizes in the orthorhombic non-centrosymmetric space group P2 1 2 1 2 1 [41]. Molecular structure is represented in Scheme 1 with atom numbering system used in Table 1, which lists the most rel- evant bond distances and angles. In 1, the asymmetric unit con- tains one Zn(II) and one Na(I) as cations and two acetylacetonate (acac) and one acetate ligands plus one ethanol molecule as depicted in Scheme 1. The Zn(II) metal ion is five-coordinated in 1387-7003/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2008.03.018 * Corresponding author. Fax: +33 472 431 160. E-mail address: luneau@univ-lyon1.fr (D. Luneau). Inorganic Chemistry Communications 11 (2008) 749–753 Contents lists available at ScienceDirect Inorganic Chemistry Communications journal homepage: www.elsevier.com/locate/inoche