Co₅/Co₈–Cluster-Based Coordination Polymers Showing High-Connected Self-Penetrating Networks: Syntheses, Crystal Structures, and Magnetic Properties

Abstract

Two novel Co(II)-cluster-based coordination polymers--namely, [Co5(μ3-OH)2(1,4-ndc)4(bix)2]n (1) and {[Co8(μ3-OH)4(1,4-ndc)6(btp)(H2O)6]·H2O}n (2)--were prepared by hydrothermal reactions of Co(II) perchlorate with 1,4-naphthalenedicarboxylic acid (1,4-H2ndc) and different N-donor coligands (bix = 1,4-bis(imidazol-1-ylmethyl)benzene and btp = 4,4'-bis(triazol-1-ylmethyl)biphenyl). In 1, 10-connected [Co5(μ3-OH)2(COO)8] clusters are extended by the μ4-1,4-ndc(2-) and trans-bix ligands to construct a rare, self-penetrating ile framework that can interestingly be regarded as the cross-link of two interpenetrating 6-connected pcu networks. While for 2, [Co8(μ3-OH)4(COO)12] clusters serve as the 8-connected nodes, which are bridged by the μ4/μ5-1,4-ndc(2-) and trans-btp ligands to afford the highest-connected uninodal self-penetrating (4(20).6(8)) network based on octacobalt clusters. A synthetic and structural comparison of 1 and 2 demonstrates that the features of auxiliary N-donor ligands play a key role in governing the in situ formed clusters and the final 3-D coordination frameworks. Magnetic susceptibility measurements indicate that complex 1 shows an antiferromagnetic interaction between the adjacent Co(II) ions, whereas 2 displays the dominant antiferromagnetic exchanges in 300-50 K and a ferrimagnetic-like behavior at lower temperatures.

Crystal structure of poly[diaquabis(μ2-biphenyl-2,4′-dicarboxylato-κ2 O:O′)tris(μ2-1,1′-biphenyl-4,4′-diylbis(1H-imidazole)-κ2 N:N′)dicobalt(II)] monohydrat, C82H64N12O11Co2

“…According to a survey of the previous references, bis(imidazole) ligands, as well-known N-donor ligands, have been widely utilized for tunability of structural frameworks [5,6]. As part of our investigations on the structural diversity, magnetism and photocatalytic properties of metal aromatic polycarboxylic frameworks, some novel Co-CPs with gas adsorption and photocatalysis and magnetic properties are reported [7][8][9][10]. Herein, 2,4′-biphenyldicarboxylic acid (H 2 bpdc) is selected to form a bridging ligand after deprotonation and reacted with a Co(II) salt.…”

Syntheses, structural diversity, magnetic properties and dye absorption of various Co(ii) MOFs based on a semi-flexible 4-(3,5-dicarboxylatobenzyloxy)benzoic acid

“…These results clearly manifest that the presence of antiferromagnetic coupling between octahedral CoIJII) ions and the structure of the [Co 3 IJμ 2 -O) 2 N 6 IJCOO) 2 ] trinuclear cluster may be responsible for this phenomenon. [30][31][32] Meanwhile, the temperature dependence of the reciprocal susceptibilities (χ M −1…”

Crystal Structures and Photoluminescence Properties of Zinc(II) and Cadmium(II) Coordination Polymers with “Y”‐Shaped Ligands

“…[1][2][3][4] In this context, the predesign and assembly of novel crystalline material by structure-directing factors, such as central metal ions, [5] organic ligands, [6] metal-ligand ratio, [7] solvents, [8] temperature, [9] pH value, [10] counterions, [11] and templates, [12] have been validated and summarized. Among them, the critical factor for the construction of coordination polymers is the rational choice of organic building block and central metal atoms.…”