萘基二膦酸钴配合物的合成、晶体结构和磁性质

基于萘二膦酸,采用水热法合成两例新型钴配合物Co₄(1,4-ndpa)₂(4,4′-bpy)₂]·5H₂O (1)和Co(1,4-ndpaH)]·1.5H₂O (2),其中1,4-ndpa^4-为1,4-萘二膦酸去质子化,4,4′-bpy为4,4′-联吡啶。在配合物1和2中,钴原子呈四配位的畸变四面体构型。配合物1的晶体结构中包含有共用顶点的四面体{CoNO₃}和{PO₃C}的梯形链,这些梯形链分别由1,4-ndpa^4-和4,4′-bpy配体与相邻的梯形链连接,形成开放的三维框架结构,结晶水分子通过氢键作用填充在骨架的空隙中。配合物2的晶体结构中包含有不同于配合物1的链结构,共用顶点四面体{CoO₄}和{PO₃C}组成的无机链仅通过1,4-ndpaH^3-配体交联形成三维开放框架结构。磁性研究表明,配合物1中Co^II存在自旋轨道耦合和/或Co^II之间存在反铁磁相互作用。

Synthesis,Crystal Structure and Magnetic Properties of Naphthalene-Based Cobalt Diphosphonates Compound

Two new cobalt diphosphonates with formulae Co₄(1,4-ndpa)₂(4,4′-bpy)₂]·5H₂O (1) and Co(1,4-ndpaH)]·1.5H₂O (2) are isolated based on naphthalene scaffold, where 1,4-ndpa^4- represents deprotonation of 1,4-naphthalene diphosphonic acid and 4,4′-bpy is 4,4′-bipyridine. The cobalt atoms are four coordinated with distorted tetrahedral geometries in both 1 and 2. Compound 1 displays a three dimensional framework structure containing ladder-like chains made up of corner-sharing tetrahedra {CoNO₃} and {PO₃C}. These ladder-like chains are then connected with adjacent ladder-like chains through 1,4-ndpa^4-and 4,4′-bpy ligands respectively. Lattice water molecules fill the gaps in the skeleton by hydrogen bond. Compound 2 has a different type of chain structure, where the inorganic chains composed of corner-sharing {CoO₄} and {PO₃C} are cross-linked by only 1,4-ndpaH^3- ligands into 3D open framework structures. Magnetic studies reveal that spin-orbit coupling and/or antiferromagnetic interaction of Co^II is observed in compound 1.