Triki Smaïl, Thétiot Franck, Vandevelde Fanny, Sala-Pala Jean, Gómez-García Carlos J
UMR CNRS 6521, Université de Bretagne Occidentale, BP 809, 29285 Brest Cedex, France.
Inorg Chem. 2005 May 30;44(11):4086-93. doi: 10.1021/ic050235h.
Reactions between CuCl2 and K2tcpd (tcpd2- = [C10N6]2- = (C[C(CN)2]3)2-) in the presence of neutral co-ligands (bpym = 2,2'-bipyrimidine, and tn = 1,3-diaminopropane) in aqueous solution yield the new compounds [Cu2(bpym)(tcpd)2(H2O)4] x 2H2O (1), [Cu(tn)(tcpd)] (2), and [Cu(tn)2(tcpd)] x H2O (3), which are characterized by X-ray crystallography and magnetic measurements. Compound 1 displays a one-dimensional structure in which the bpym ligand, acting with a bis-chelating coordination mode, leads to [Cu2(bpym)]4+ dinuclear units which are connected by two mu2-tcpd2- bridging ligands. Compound 2 consists of a three-dimensional structure generated by [Cu(tn)]2+ units connected by a mu4-tcpd2- ligand. The structure of 3 is made up of centrosymmetric planar [Cu(tn)]2+ units connected by a mu2-tcpd2- ligand leading to infinite zigzag chains. In compounds 1 and 3, the bridging coordination mode of the tcpd2- unit involves only two nitrogen atoms of one C(CN)2 wing, while in 2, this ligand acts via four nitrogen atoms of two C(CN)2 wings. Despite this difference, the structural features of the tcpd2- units in 1-3 are essentially similar. Magnetic measurements for compound 1 exhibit a maximum in the chi(m) vs T plot (at approximately 150 K) which is characteristic of strong antiferromagnetic exchange interactions between the Cu(II) metal ions dominated by the magnetic exchange through the bis-chelating bpym. The fit of the magnetic data to a dimer model gives J and g values of -90.0 cm(-1) and 2.12, respectively. For compounds 2 and 3 the thermal variations of the magnetic susceptibility show weak antiferromagnetic interactions between the Cu(II) metal ions that can be well reproduced with an antiferromagnetic regular S = 1/2 chain model that gives J values of -0.07(2) and -0.18(1) cm(-1) with g values of 2.12(1) and 2.13(1) for compounds 2 and 3, respectively (the Hamiltonian is written in all the cases as H = -2JS(a)S(b)).
在水溶液中，氯化铜（CuCl₂）与K₂tcpd（tcpd²⁻ = [C₁₀N₆]²⁻ = (C[C(CN)₂]₃)₂⁻）在中性共配体（bpym = 2,2'-联嘧啶，tn = 1,3 - 二氨基丙烷）存在下反应，生成新化合物[Cu₂(bpym)(tcpd)₂(H₂O)₄]·2H₂O（1）、[Cu(tn)(tcpd)]（2）和[Cu(tn)₂(tcpd)]·H₂O（3），通过X射线晶体学和磁性测量对其进行了表征。化合物1呈现一维结构，其中bpym配体以双螯合配位模式起作用，形成[Cu₂(bpym)]⁴⁺双核单元，这些单元通过两个μ₂ - tcpd²⁻桥连配体相连。化合物2由[Cu(tn)]²⁺单元通过μ₄ - tcpd²⁻配体连接形成三维结构。化合物3的结构由中心对称的平面[Cu(tn)]²⁺单元通过μ₂ - tcpd²⁻配体连接形成无限之字形链。在化合物1和3中，tcpd²⁻单元的桥连配位模式仅涉及一个C(CN)₂侧翼的两个氮原子，而在2中，该配体通过两个C(CN)₂侧翼的四个氮原子起作用。尽管存在这种差异，但1 - 3中tcpd²⁻单元的结构特征基本相似。化合物1的磁性测量在χ(m)对T的图中显示出最大值（约150 K），这是由通过双螯合bpym进行磁交换主导的Cu(II)金属离子之间强反铁磁交换相互作用的特征。将磁性数据拟合到二聚体模型得到的J和g值分别为 - 90.0 cm⁻¹和2.12。对于化合物2和3，磁化率的热变化表明Cu(II)金属离子之间存在弱反铁磁相互作用，这可以用反铁磁规则S = 1/2链模型很好地再现，对于化合物2和3，该模型给出的J值分别为 - 0.07(2)和 - 0.18(1) cm⁻¹，g值分别为2.12(1)和2.13(1)（在所有情况下哈密顿量写为H = - 2JS(a)S(b)）。
