Solvent-controlled metal coordination polymers of Co(ii) with different topological structures and properties

Abstract

Three new Co(II) coordination polymers {[Co(TTPA)·(H₂O)₂]·H₂O}_n (Co-1), {[Co₃(TTPA)₃(H₂O)₂]·4DMSO}_n (Co-2), and {[Co(TTPA)·(H₂TTPA)]·2DMSO}_n (Co-3) were successfully synthesized based on a multidentate bridging organic ligand 2,5-bis-(1,2,4-triazol-1-yl)-terephthalic acid (H₂TTPA) under solvent-controlled thermal reaction conditions. Single-crystal X-ray diffraction studies show that complex Co-1 has a 4,4-linked two-dimensional layered structure, which is formed in a H₂O–DMF–methanol mixed solvent. Co-2 displays a novel complicated topology—a 4,4,5,6-c tetranodal 3D framework with 1D channels along the a direction and is obtained under the condition of an equal volume ratio of DMSO and methanol as a solvent. Co-3 presents another 3D porous framework with a 4,6-dinodal 3D framework with a pore volume of 36.3% and is synthesized under the volume ratio of DMSO to methanol of 3 : 1. In addition, the static and/or dynamic magnetic properties of the three polymers were determined. The microporous MOF Co-2 also underwent gas sorption measurements.