We have synthesized three new cobalt based inorganic-organic hybrid materials by solvothermal method, these structure have either angular or linear trimeric cobalt cluster as a secondary building unit. In case of compounds 1 and 2, the cobalt centers were corner shared through common bridging –OH group to form the triangular cluster. Interestingly in compound 1, the monomeric cobalt center is linked with framework while in compound 2 the monomeric cobalt unit is trapped inside the pore of the framework. In compound 3, the cobalt centers are corner shared to form the linear trimeric cluster. These trimeric cobalt clusters are connected through BTB ligands to form two-dimensional coordination polymer structure. All three structures have common BTB (1,3,5-Tris(4-carboxyphenyl)benzene) ligand, whereas in case of compound 1 and 2, BPE (1,2-bis (4-pyridyl) ethane) and for 3, DPB (1,4-Di(4-pyridyl)benzene) have been used as co-ligand. The magnetic measurements revealed the large and positive values of θ_CW in compounds 1 and 2. This implies that the dominant interaction between the Co spins are antiferromagnetic in nature. In case of compound 3, the structure is quite different from the other two compounds. In compound 3 the coupling between the Co-atoms drastically reduce compared to compounds 1 and 2, respectively, resulting in a paramagnetic behavior. We have also measured the optical band gap energy for all three compounds and results show that the band gap is relatively low and it is in the range of 1.82 eV to 1.89 eV.

我们已经通过溶剂热法合成了三种新型的钴基无机-有机杂化材料，这些结构具有角型或线性三聚体钴簇作为二级结构单元。在化合物1和2的情况下，钴中心通过共同的-OH基桥接形成角簇，从而形成三角形簇。有趣的是，在化合物1中，单体钴中心与骨架相连，而在化合物2中，单体钴单元被捕集在骨架的孔中。在化合物3中，钴中心被角共享以形成线性三聚体簇。这些三聚体钴簇通过BTB配体连接形成二维配位聚合物结构。这三个结构都具有相同的BTB（1,3,5-Tris（4-羧苯基）苯）配体，而对于化合物1和2，则是BPE（1,2-双（4-吡啶基）乙烷）和对于3而言， DPB（1，4-二（4-吡啶基）苯）已被用作共配体。磁测量显示化合物1和2中的_θCW值较大且为正值。这意味着Co自旋之间的主要相互作用本质上是反铁磁性的。如果是化合物3，其结构与其他两种化合物完全不同。与化合物1和2相比，在化合物3中，Co原子之间的耦合急剧减少，从而导致顺磁行为。我们还测量了所有三种化合物的光学带隙能量，结果表明，带隙相对较低，在1.82 eV至1.89 eV的范围内。