New Types of Heterospin Complexes from trans-Oxamido-Bridged Copper(II) Binuclear Units and Nitronyl Nitroxide Radicals: Crystal Structure and Magnetic Characterization
详细信息 查看全文
- 作者：Zhiliang Liu ; Zhengliang Lü ; Deqing Zhang ; Zonghui Jiang ; Licun Li ; Caiming Liu ; and Daoben Zhu
- 刊名：Inorganic Chemistry
- 出版年：2004
- 出版时间：October 18, 2004
- 年：2004
- 卷：43
- 期：21
- 页码：6620 - 6627
- 全文大小：278K
- 年卷期：v.43,no.21(October 18, 2004)
- ISSN：1520-510X
文摘
Three new heterospin complexes derived from trans-oxamido-bridged copper(II) binuclear units [Cu2(oxen), oxen= N,N-bis(2-aminoethyl)oxamide] and pyridine-substituted nitronyl nitroxides (o-, m-, and p-PYNN) were synthesizedand characterized structurally and magnetically. Complexes 1 and 2 are four-spin complexes. Interestingly, it isfound that in complex 3, the Cu(II) ions and m-PYNN units are arranged to form 1D double-stranded helical chains,which to the best of our knowledge is the first example of a metal nitronyl nitroxide complex with such a 1D helicalstructure. The temperature dependencies of the magnetic susceptibilities of 1 and 2 were fitted to the four-spinmodel with the Hamiltonian 
= -2J
Cu1Cu2 - 2j(Cu1rad1 - Cu2rad2), leading to J = -150.5 cm-1 and j = 47.2cm-1 for complex 1 and J = -191.7 cm-1 and j = -18.9 cm-1 for complex 2. The temperature dependence ofthe magnetic susceptibility of complex 3 was approximately simulated with a simple model composed of a dimerof Cu(II) ions and two m-PYNN molecules. The best fitting leads to the values of J = -183.0 cm-1 and zJ' =-0.55 cm-1 for the magnetic exchange of two Cu(II) ions through the oxamide bridge and that between the dimerof Cu(II) ions and two m-PYNN molecules, respectively. The antiferromagnetic exchange of oxamido-bridged Cu(II)ions in complexes 1-3 is strong. The strength of such antiferromagnetic interactions is also similar for the threecomplexes.
= -2JCu1Cu2 - 2j(Cu1rad1 - Cu2rad2), leading to J = -150.5 cm-1 and j = 47.2cm-1 for complex 1 and J = -191.7 cm-1 and j = -18.9 cm-1 for complex 2. The temperature dependence ofthe magnetic susceptibility of complex 3 was approximately simulated with a simple model composed of a dimerof Cu(II) ions and two m-PYNN molecules. The best fitting leads to the values of J = -183.0 cm-1 and zJ' =-0.55 cm-1 for the magnetic exchange of two Cu(II) ions through the oxamide bridge and that between the dimerof Cu(II) ions and two m-PYNN molecules, respectively. The antiferromagnetic exchange of oxamido-bridged Cu(II)ions in complexes 1-3 is strong. The strength of such antiferromagnetic interactions is also similar for the threecomplexes.