The regulation research of topology and magnetic exchange models of CPs through Co(II) concentration adjustment

We have designed and synthesized two new Co-CPs by modulating the concentration of cobalt ions, namely [Co3(HL)2(4,4'-bibp)3(H2O)4]n (1) and {[Co9(L)4(4,4'-bibp)4(H2O)6(mu 2-OH)2].4,4'-bibp.2H2O}n (2) (H4L = 1,1',2',1''-terphenyl-4,4',4'',5'-tetracarboxylic acid and 4,4'-bipb = 1,4-di(pyridin-4-yl)benzene). CP 1 is a threedimensional (3D) pillar-layered network constructed by HL3- and bridging 4,4'-bibp co-ligands with a 10-connected (424.512.68.7) topology. CP 2 is a 3D reticular framework with (4,4,5,5,6)-connected topology. The structural diversity of the two CPs suggests that the cluster numbers and the different local coordination geometries of Co(II) ions can be induced by the reaction material ratio. Focusing on the bridging system, CP 1 cnsists of centrosymmetric trinuclear octahedral cobalt(II) units, and within the units, the cobalt(II) ions are found to be ferromagnetically coupled. CP 2 cnsists of centrosymmetric nonanuclear cobalt(II) units, including five octahedral and four trigonal-bipyramidal cobalt(II) ions. Antiferromagnetic interactions are observed in the partial triangular units, and also in the other parts, showing an overall antiferromagnetic behavior.

Automated summary

We have synthesized two new Co-CPs with different structures by adjusting the concentration of cobalt ions. CP 1 is a three-dimensional pillar-layered network with a 10-connected topology, while CP 2 is a three-dimensional reticular framework with a (4,4,5,5,6)-connected topology. The structural diversity of the two CPs is attributed to the variation of cluster numbers and local coordination geometries of Co(II) ions. The magnetic interactions between cobalt ions in CP 1 and CP 2 are different, with ferromagnetic coupling in CP 1 and antiferromagnetic behavior in CP 2.