Synthesis, structure and properties of a fumarate bridged Ni(II) coordination polymer Sanchay J. Bora 1 , Birinchi K. Das ⇑ Department of Chemistry, Gauhati University, Guwajhati 781 014, India article info Article history: Received 14 March 2011 Received in revised form 20 May 2011 Accepted 21 May 2011 Available online 13 June 2011 Keywords: 1-D coordination polymer Nickel(II) fumarate 4-Cyanopyridine ligand Graph-set analysis Metallosupramolecular assembly abstract A 1-D coordination polymer catena[l-fumaratobis(4-cyanopyridine)diaquanickel(II)],[Ni(l-C 4 H 2 O 4 )(4- CNpy) 2 (H 2 O) 2 ] n 1 has been synthesized and structurally characterized. Compound 1 is monoclinic, P2 1 / c with unit cell parameters a = 8.8759(9) Å, b = 11.4112(11) Å, c = 8.8908(9) Å, b = 106.010(6)°, V = 865.6(1) Å 3 , Z = 2 and D calc. = 1.600 g cm 3 . The structure refined to R 1 = 0.0245, wR 2 = 0.0626 for all 2014 unique reflections and 152 parameters; GooF = 1.056. It consists of a polymeric chain of nearly octa- hedral Ni 2+ centers bridged by bidentate fumarato ligands. Non-covalent interactions lead these chains to aggregate into an interesting metallosupramolecular assembly. Indexed PXRD pattern, solid state UV– vis–NIR spectral data, thermogravimetric behavior and variable temperature magnetic susceptibility data on 1 are presented. Ó 2011 Elsevier B.V. All rights reserved. 1. Introduction Coordinated ligand systems containing electron donor and acceptor sites lead to metallosupramolecular assemblies [1], and in this context 4-cyanopyridine (4-CNpy) with the electron -withdrawing nitrile group as the acceptor and the pyridyl nitro- gen as the donor represents a suitable candidate [2]. Presence of two regions of delocalized electron density also brings in the pos- sibility of pp interactions so as to direct preferences for thermo- dynamically favoured solid state structures [3,4]. On the other hand, presence of the dianion of fumaric acid (C 4 H 2 O 2 4 ) as a ligand in metal organic compounds is known to give coordination poly- mers of various dimensionalities [5,6]. Coordination polymer is a family which is composed of 1-D chains, 2-D sheets, and 3-D frameworks of building blocks connected via metal ligand coordi- nation bonds. Hydrogen bonding and pp stacking interaction may further be utilized to generate low-dimensional coordination polymers into supramolecular networks of higher dimensionality. Coordination polymers based on transition metals and multi- functional organic ligands have received considerable recent atten- tion in the design of supramolecular assemblies having potential applications in diverse fields such as catalysis, cooperative magne- tism, luminescence, NLO behavior, electrical conductivity, among others [7]. It is also a notable fact that such compounds have been described as promising materials for gas sorption as well as storage [8,9]. These compounds have also been described as precursors for the synthesis of nanomaterials [10,11]. In this paper we describe our results on the synthesis, crystal structure determination and properties of a new 1-D coordination polymer of Ni(II), formulated as [Ni(l-C 4 H 2 O 4 )(4-CNpy) 2 (H 2 O) 2 ] n 1. 2. Experimental 2.1. Materials Reagents and solvents used in this work were used as obtained from commercial sources. Disodium fumarate was prepared by evaporating a NaOH-neutralized aqueous solution of fumaric acid. The off-white residue so obtained was dried at 110 °C. Ni(H 2 O) 3 (SO 4 )(4-CNpy) 2 H 2 O has been prepared by following a published method [12]. 2.2. Instrumentation The C,H,N analysis was performed using a Perkin–Elmer 2400 Series II CHNS/O Analyzer. FT-IR spectra were recorded in a Perkin–Elmer RX1 spectrophotometer in the mid-IR region (4000–400 cm 1 ) for KBr pellets. The solid state UV–vis–NIR (240–2600 nm) spectra were obtained using a Hitachi U-4100 spectrophotometer equipped with an integrating sphere. BaSO 4 powder was used as reference (100% reflectance). Absorption data were calculated from the diffuse reflectance data using the Kub- elka–Munk function (a/S = (1  R) 2 /2R where a is the absorption 0022-2860/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.molstruc.2011.05.039 ⇑ Corresponding author. Tel.: +91 361 2570535; fax: +91 361 2700311. E-mail addresses: snachay.bora@gmail.com (S.J. Bora), das_bk@rediffmail.com (B.K. Das). 1 Present address: Pandu College, Guwahati 781 012, India. Journal of Molecular Structure 999 (2011) 83–88 Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstruc