Old dog, new tricks: 2,2′-biphenol as a bridging and book-end ligand in discrete and extended Co(ii) architectures

Abstract

We report the first Co(II) based discrete and extended network materials comprising the 2,2´-biphenol ligand. We first present the synthesis and magnetic characterisation of the Co(II) dinuclear complexes [Co(II) 2 (L) 2 (py) 4 ].2EtOH (1) and [Co(II) 2 (L) 2 (4-pic) 4 ].2LH 2 (2), both of which exhibit antiferromagnetic exchange between their Co(II) centres. The introduction of the co-ligand 2-hydroxypyridine (2-hpH) leads to the production of planar octametallic complex [Co(II) 8 (OMe) 2 (L) 4 (LH) 2 (2-hp) 4 (MeCN) 4 ].MeCN (3). Magnetic susceptibility and magnetisation measurements on 3 indicate dominant ferromagnetic exchange between the Co(II) centres. We also 10 describe the first Co(II) / 2,2'-biphenol extended networks in the shape of the 1D coordination polymer {[Co(II)(LH)(4,4-tmdp) 2 (NO 3 )](LH 2 )} n (4) (where 4,4'-tmdp = 4,4'-trimethylenedipyridine) and the 2D brickwall network [Co(II)(LH)(trans-bpe) 1.5 (NO 3 )] (5) (where trans-bpe = trans-1,2-bis(4-pyridyl)ethylene), comprising T-shaped nodes.

Mesoporous MOF Based on a Hexagonal Bipyramid Co8-Cluster: High Catalytic Efficiency on the Cycloaddition Reaction of CO2 with Bulky Epoxides

“…Interestingly, each O 2– anion bridges four Co atoms to give a Co 4 (μ 4 -O) tetrahedron and three such tetrahedrons are fused together via edge sharing of axial Co01···Co01 to form a hexagonal bipyramid Co 8 (μ 4 -O) 3 cluster, with the remaining coordination sites capped by twelve carboxylate groups and six water molecules. We note that several octanuclear cobalt oxide clusters have been documented in discrete molecules − or polymeric species. ,,− In these cases, the common configurations of octanuclear cobalt oxide clusters are either the Co 4 (μ 3 -O) 4 cubane with four dangling cobalt atoms ,− or Co 8 (μ 4 -OH) 6 cubes. , Obviously, the present hexagonal bipyramid Co 8 (μ 4 -O) 3 cluster formed by three fused Co 4 (μ 4 -O) tetrahedrons is distinct from those of previously reported octacobalt clusters. ,,− …”

Octanuclear Cobalt(II) Cluster-Based Metal–Organic Framework with Caged Structure Exhibiting the Selective Adsorption of Ethane over Ethylene

“…Each μ 3 -OH group is further coordinated to a Co2 atom to generate four-pointed star-like Co 8 (μ 3 -OH) 4 clusters with Co1···Co2, Co1···Co2C, and Co1···Co1C of 3.141, 3.232, and 3.932 Å (Figure S4), respectively. Many kinds of octanuclear cobalt oxide clusters with diverse structures have been documented. , The common configurations for octanuclear cobalt oxide clusters are the Co 4 (μ 3 -O) 4 cubic cluster with four dangling cobalt atoms and three fused Co 4 (μ 3 -O) 4 cubic clusters sharing the faces (I and II in Figure S4). , Obviously, the present unique octanuclear cobalt oxide cluster formed from a eight-membered Co 4 (μ 3 -O) 4 ring and four dangling cobalt atoms is distinct from those of the previously reported octanuclear cobalt oxide clusters (Figure S4).…”

Enhancing the Magnetic Anisotropy in Low-Symmetry Dy-Based Complexes by Tuning the Bond Length

“…To better understand the effect of bond length tuning on the magnetic dynamics, we summarized some previously reported nona-coordinated Dy-SMMs, in which the shortest bond distances change from 2.203 to 2.384 Å, and the bond length differences Δ r around the Dy III center vary between 0.197 and 0.613 Å (Table ). − Careful analysis of the magnetostructural parameters indicates that the shorter the shortest bond length and the greater the bond length difference, the better the performance of the SMMs.…”