Casarin Maurizio, Corvaja Carlo, Di Nicola Corrado, Falcomer Daniele, Franco Lorenzo, Monari Magda, Pandolfo Luciano, Pettinari Claudio, Piccinelli Fabio
Department of Chemical Sciences, University of Padova, Via Marzolo, 1, I-35131 Padova, Italy.
Inorg Chem. 2005 Sep 5;44(18):6265-76. doi: 10.1021/ic050678l.
The reactions of pyrazole (Hpz) with some copper(II) carboxylates in the presence of water yield trinuclear copper derivatives characterized by the triangular core [Cu3mu3-OH)(mu-pz)3(RCOO)2] (R = H, C2H5, C3H7). Copper(II) formate gives [Cu3(mu3-OH)(mu-pz)3(HCOO)2(Hpz)2] (1), whereas copper propionate and butyrate afford [Cu3(mu3-OH)(mu-pz)3(C2H5COO)2(EtOH)] (2) and [Cu3(mu3-OH)(mu-pz)3(C3H7COO)2(MeOH)(H2O)] (3), respectively, both containing solvent molecules coordinated to copper atoms. Magnetic susceptibilities are consistent with a single unpaired electron for each trinuclear unit of 1-3, and EPR measurements indicate that higher spin states, generated by exchange coupling between copper atoms, may be populated at room temperature. Density-functional calculations provide the description of the electronic structures of 1-3, allowing, at the same time, the assignment of their UV-vis absorption spectra. X-ray molecular structure determinations show that triangular trinuclear units of 1 are connected to each other through single formate bridges, forming one-dimensional (1D) zigzag coordination polymers, whereas in 2 and 3, two oxygen atoms of two carboxylate ions doubly bridge two copper atoms of different triangles, thus generating hexanuclear units. Moreover, in 2, two other propionate ions link together two hexanuclear units yielding a 12-membered cycle and giving rise to 1D coordination polymers. The supramolecular assemblies of 1-3 are compared to that of the previously reported trinuclear triangular copper(II) derivative [Cu3(mu3-OH)(mu-pz)3(CH3COO)2(Hpz)] (A), where a two-dimensional (2D) coordination polymer is present. The reactions of 3,5-dimethylpyrazole (Hpz) with copper(II) carboxylates in the same conditions yield 1:2 Cu(RCOO)2/Hpz adducts.
吡唑（Hpz）与一些羧酸铜（II）在水存在下反应生成三核铜衍生物，其特征为三角核心[Cu3μ3 - OH)(μ - pz)3(RCOO)2]（R = H、C2H5、C3H7）。甲酸铜生成[Cu3(μ3 - OH)(μ - pz)3(HCOO)2(Hpz)2]（1），而丙酸铜和丁酸铜分别得到[Cu3(μ3 - OH)(μ - pz)3(C2H5COO)2(EtOH)]（2）和[Cu3(μ3 - OH)(μ - pz)3(C3H7COO)2(MeOH)(H2O)]（3），二者均含有与铜原子配位的溶剂分子。磁化率与1 - 3的每个三核单元有单个未成对电子一致，电子顺磁共振测量表明，由铜原子间交换耦合产生的较高自旋态可能在室温下存在。密度泛函计算提供了1 - 3电子结构的描述，同时也对它们的紫外 - 可见吸收光谱进行了归属。X射线分子结构测定表明，1的三角三核单元通过单个甲酸桥相互连接，形成一维（1D）锯齿状配位聚合物，而在2和3中，两个羧酸根离子的两个氧原子双桥连不同三角形的两个铜原子，从而生成六核单元。此外，在2中，另外两个丙酸根离子将两个六核单元连接在一起，形成一个12元环，产生1D配位聚合物。将1 - 3的超分子组装与先前报道的三核三角铜（II）衍生物[Cu3(μ3 - OH)(μ - pz)3(CH3COO)2(Hpz)]（A）的进行比较，后者存在二维（2D）配位聚合物。3,5 - 二甲基吡唑（Hpz）与羧酸铜（II）在相同条件下反应生成1:2的Cu(RCOO)2/Hpz加合物。
