Reaction of the metalloligand IrIII(ppy-COOH)3 and the anisotropic paramagnetic CoII ion under solvothermal conditions resulted in a metal–metalloligand coordination polymer, [CoII3(μ3-O)(μ-OH2)IrIII(ppy-COO)2(ppy-COOH)}2(H2O)4]·2DMF·xH2O (I). It consists of trimeric Co3O secondary building units (SBUs) bridged by pairs of Ir to form chains of alternate orthogonal squares. The compound undergoes two single-crystal to single-crystal transformations while retaining its general structural features. A chemical transformation occurs to give [CoII3(μ3-O)IrIII(ppy-COO)2(ppy-COOH)}2(H2O)4(DMF)]·DMF·H2O (II) by soaking in acetone, where a bridging water molecule departs and the solvent DMF bonds to the vacant site of the Co center. Both I and II undergo a temperature-induced transformation to [CoII3(μ3-O)IrIII(ppy-COO)2(ppy-COOH)}2(H2O)3(DMF)]·DMF (III), where one more coordinated water molecule is lost. The major difference in the three phases is in the Co coordination spheres, which have considerable consequences on the magnetism. Compound I displays paramagnetism down to 2 K, whereas II and III show weak ferromagnetism with TC values of 14 and 17 K, respectively.
在溶剂热条件下,
金属
配体IrIII(ppy-COOH)3和异向性顺磁性CoII离子的反应产生了
金属-
金属
配体配合聚合物[CoII3(μ3-O)(μ-OH2)IrIII(ppy-COO)2(ppy-COOH)}2(
H2O)4]·2
DMF·x (I)。它由三聚Co3O二级结构单元(SBU)组成,这些单元由成对的Ir桥接,形成交替的正交方块链。该化合物在保持其一般结构特征的同时经历了两次单晶到单晶的转变。通过在
丙酮中浸泡,发生
化学转变,形成[CoII3(μ3-O)IrIII(ppy-COO)2(ppy-COOH)}2( )4(
DMF)]·
DMF· (II),其中桥接
水分子离开,溶剂
DMF与Co中心的空位结合。I和II都经历了温度诱导的转变,形成[CoII3(μ3-O)IrIII(ppy-COO)2(ppy-COOH)}2( )3(
DMF)]·
DMF (III),其中又失去了一个配位
水分子。三个阶段的主要区别在于Co的配位层,这对磁性有相当大的影响。化合物I在2 K以下表现出顺磁性,