Synthesis and structural studies of some fluorescent group XII metal complexes with a terpyridine based ligand Ali Nemati Kharat ⇑ , Abolghasem Bakhoda, Sara Zamanian School of Chemistry, University College of Science, University of Tehran, Tehran, Iran article info Article history: Received 5 September 2010 Accepted 13 January 2011 Available online 31 January 2011 Keywords: 4 0 -(2-Thienyl)-2,2 0 ,6 0 ,2 00 -terpyridine Cadmium(II) Mercury(II) X-ray crystallography Fluorescence spectroscopy abstract Three 4 0 -(2-thienyl) substituted terpyridine (thioterpy) complexes of cadmium(II) and mercury(II) have been synthesized and fully characterized by spectroscopies. According to the crystallographic studies, the packing of these complexes was stabilized by several intermolecular interactions such as hydrogen bonding, C–Hp and pp. Finally, the florescent properties of the prepared complexes have been investigated. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction 2,2 0 ;6 0 ,2 00 -Terpyridine (terpy) based ligands are noticeable build- ing blocks in both organic and inorganic supramolecular chemistry, with their non-covalent pp stacking ability, directional hydrogen bonding and coordination properties [1,2]. The luminescence prop- erties stemming from the conjugated aromatic cores of these mol- ecules have been studied with varying applications including liquid crystals, photosensitizers and studying biochemical DNA interca- lating reaction mechanisms [3–5]. Moreover, there has been con- siderable interest in terpy complexes because of their properties as intercalating metalloreagents to nucleic acids as well as their intriguing spectroscopic behavior [6,7]. The design and construc- tion of inorganic–organic hybrid materials, containing group XII metal ions such as Cd 2+ and Hg 2+ , have attracted considerable atten- tion in recent years for their special functional properties such as optics [8,9], separation [10,11] and catalysis [12–16], as well as the variety of architectures and topologies [17–20]. Recently, metal complexes based on terpy and its derivatives have been extensively investigated [21–24]. Che and co-workers have synthesized a new class of Zinc-terpyridyl based polymer via self-assembly reactions, which are promising light-emitting materials for polymer light- emitting diodes [25]. Interestingly, both Alcock et al. [26] and Hannan et al. [24] carefully designed terpyridine-based ligands and obtained luminescent metallo-supramolecular coordination polymers assembled through pp interactions and the blue or bluish violet emission is attributed to the pp / transition of the ligands. The donor–acceptor system is an effective approach to adjust the optical properties of organic-inorganic hybrid materials [27,28]. Herein, we present the synthesis of a series of 4 0 -(2-thienyl) substituted terpyridine (thioterpy) complexes with Cd 2+ and Hg 2+ ions. Further, the spectral properties, solid state structures and luminescent characteristics of these complexes are presented. 2. Experimental 2.1. Materials and instruments The ligand was synthesized according to the previously pub- lished procedures, with a slight modification [29]. All solvents were obtained from commercial sources and were used without further purification. 2-Acetylpyridine, thiophene-2-carboxalde- hyde, ammonium hydroxide and potassium tert-butoxide were purchased from Merck chemicals and were used as received. The metal salts were obtained from Fluka and Merck. Melting points are uncorrected and were obtained with an Electrothermal 9200 melting point apparatus. Infrared spectra from 250 to 4000 cm 1 of solid samples were taken as 1% dispersions in CsI pellets using a Shimadzu-470 spectrometer. 1 H and 13 C NMR spectra were recorded at room temperature on a Bruker AVANCE 300 MHz. The NMR spectra are referenced to Me 4 Si as an external standard. Elemental analysis was performed using a Heraeus CHN–O Rapid analyzer. UV–Vis spectra were recorded on a Shimadzu 2100 spec- trometer using a 1 cm path length cell. Corrected luminescence 0277-5387/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.poly.2011.01.024 ⇑ Corresponding author. Tel.: +98 21 61112499; fax: +98 21 66495291. E-mail address: alnema@khayam.ut.ac.ir (A.N. Kharat). Polyhedron 30 (2011) 1134–1142 Contents lists available at ScienceDirect Polyhedron journal homepage: www.elsevier.com/locate/poly