Influence of Copper(II) and Nickel(II) Ions in the Topology of Systems Based on a Flexible Bis-Oxamate and Bipyridine Building Blocks

• Published in: Crystal growth & design 2014-11, Vol.14 (11), p.5929-5937
• Main Authors: do Pim, Walace D, Simões, Tatiana R. G, Oliveira, Willian X. C, Fernandes, Isabella R. A, Pinheiro, Carlos B, Lloret, Francesc, Julve, Miguel, Stumpf, Humberto O, Pereira, Cynthia L. M
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Physics; Solid-solid transitions; Specific phase transitions
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg501134y

Single crystals of the mononuclear bis-oxamate nickel(II) complex [Ni(bipy)(H2edpba)]·dmso (1) are obtained by reacting [Ni(bipy)Cl2]·H2O and the flexible K2(H2edpba) ligand [bipy = 2,2′-bipyridine; H4edpba = N,N′-2,2′-ethylenediphenylenebis(oxamic acid)]. The reaction of 1 with copper(II) ions resulted in two products in which the replacement of the nickel(II) ion by copper(II) took place: the chain compound [Cu(bipy)(H2edpba)] n ·3nH2O·ndmso [dmso = dimethyl sulfoxide] (2) and the analogous chain compound without dmso crystallization molecules [Cu(bipy)(H2edpba)] n ·1.5nH2O (3a) in its polycrystalline form. The reaction of [Cu(bipy)Cl2] and K2(H2edpba) yielded single crystals of [Cu(bipy)(H2edpba)] n ·1.5nH2O (3b). The H2edpba2– ligand exhibits the anti conformation in 1, 2, and 3b, but it adopts different coordination modes: terminal bis-bidentate (1) and bridging bis-bidentate (2 and 3b) through the two pairs of carbonyl-oxygen atoms of the two oxamate arms. Magnetic susceptibility measurements carried out on a polycrystalline sample of 3b in the temperature range 1.9–295 K showed the occurrence of very weak intrachain antiferromagnetic interactions [J = −0.40 cm–1, the Hamiltonian being defined as H = −J ∑ i S i · S i+1], in agreement with the large values of the copper–copper separation [8.308(3) Å].