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

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• 作者：Walace D. do Pim ; Tatiana R. G. Sim玫es ; Willian X. C. Oliveira ; Isabella R. A. Fernandes ; Carlos B. Pinheiro ; Francesc Lloret ; Miguel Julve ; Humberto O. Stumpf ; Cynthia L. M. Pereira
• 刊名：Crystal Growth & Design
• 出版年：2014
• 出版时间：November 5, 2014
• 年：2014
• 卷：14
• 期：11
• 页码：5929-5937
• 全文大小：475K
• ISSN：1528-7505

文摘

Single crystals of the mononuclear bis-oxamate nickel(II) complex [Ni(bipy)(H₂edpba)]路dmso (1) are obtained by reacting [Ni(bipy)Cl₂]路H₂O and the flexible K₂(H₂edpba) ligand [bipy = 2,2鈥?b>-bipyridine; H₄edpba = N,N鈥?2,2鈥?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路3nH₂O路ndmso [dmso = dimethyl sulfoxide] (2) and the analogous chain compound without dmso crystallization molecules [Cu(bipy)(H₂edpba)]_n路1.5nH₂O (3a) in its polycrystalline form. The reaction of [Cu(bipy)Cl₂] and K₂(H₂edpba) yielded single crystals of [Cu(bipy)(H₂edpba)]_n路1.5nH₂O (3b). The H₂edpba^{2鈥?/sup> 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鈥?95 K showed the occurrence of very weak intrachain antiferromagnetic interactions [J = 鈭?.40 cm鈥?, the Hamiltonian being defined as H = 鈭?i>J 鈭?sub>iS_i路S_i+1], in agreement with the large values of the copper鈥揷opper separation [8.308(3) 脜].}