New Solvatomorph of Tetrakis(Μ2-Acetato-O,O')-Bis(Isonicotinamide-N)-Di-Copper(II): Synthesis, IR, TGA and X-Ray Study

Abstract

Abstract. Dinuclear tetracarboxylato-bridged copper(II) complex, [Cu 2 (OAc) 4 (ina) 2 ]·2dmso (1), where OAc -= CH 3 COO -, ina=isonicotinamide and dmso=dimethylsulfoxide, has been prepared and crystal structure has been determined by single X-ray diffraction. The compound consists of dinuclear units, in which two Cu(II) ions are bridged by four syn,syn-η 1 :η 1 :μ-acetato bridges, showing a paddle-wheel cage-type with a square-pyramidal geometry. In the crystal structure, intermolecular N-H···O hydrogen bonds link the molecules into a 1D linear chain.Keywords: copper, isonicotinamide, X-ray, paddle-wheel structure. IntroductionThe design and preparation of metal-organic frameworks have attracted intense interest in the fi eld of supramolecular chemistry and crystal engineering owing to their potential applications as well as their structural variations that are currently of interest in the fi eld of materials [1][2][3][4][5][6][7]. A successful strategy in building such networks is to employ appropriate bridging ligands that can bind metal ions in different modes and provide a possible way to achieve diverse dimensionalities. Copper(II) metal-organic frameworks are of considerable interest because of their structural and photoluminescent biological function, catalytic and magnetic properties [8][9][10][11]. Isonicotinamide and its related compounds are reported to represent a group of small molecules as a drug candidate to prevent and/or reverse diabetes by protecting β-cells from damage and death [12].The retrieval of Cambridge Structural Database (CSD) revealed that the combination of Cu(II) with isonicotinamide resulted in structural diversity, including mono- [13][14][15], binuclear [14,[16][17][18], 1D [7,16,[19][20][21] and 2D polymeric arrays [7,22,23]. In all studies isonicotinamide coordinates to the copper(II) ion in a monodentate form through the pyridine N atom or in a bidentate one [16] thus providing possibilities for polymeric coordination networks. Pyridine-2,5-dicarboxylic acid combines the advantages of both organic multicarboxylic acids and heteroaromatic compounds and displays versatile coordination modes through its one N atom and four carboxylate O atoms, which in alliance with Cu(II) leads to the formation of coordination homometallic [23][24][25][26][27] and/or heterometallic [26,[28][29][30] polymers. With that in mind, in this contribution, we intended to extend the dimensionality of a new coordination compound obtained by the combination of isonicotinamide with pyridine-2,5-dicarboxylate ligands. However, in the synthetic conditions we were unable to obtain any new coordination compounds with simultaneous presence of pyridine-2,5-dicarboxylic acid and isonicotinamide ligand in one molecule, and a new solvatomorph of tetrakis(μ 2 -acetato-O,O')-bis(isonicotinamide-N)-di-copper(II) was obtained instead. So, we report herein the synthesis and X-ray characterization of a binuclear mixed-ligand Cu(II) complex, [Cu 2 (OAc) 4 (ina) 2 ]·2dmso (1), where OAc -= CH 3 COO -, ina = isonicotinam...

Solvent dependent formation of Cu(II) complexes based on isonicotinamide ligand

“…Compounds 2a and 6 have been previously reported by C.B. Aakeröy et al [26], and compound 5 by D. Chisca et al [27] but in all the cases via different synthetic method that the described in this paper. Compound 6 was directly isolated and crystallized in the monomeric form without the previous synthesis of the paddle-wheel array.…”