Influence of Water Ligands on Structural Diversity: From a One-Dimensional Linear Coordination Polymer to Three-Dimensional Ferrimagnetic Diamondoid Metal−Organic Frameworks

Abstract

Four three-dimensional (3D) metal−organic frameworks [Mn3(3-Me-sal)4(py)4] n (1), [Mn3(4-Me-sal)4(py)4(MeOH)] n ·n(H2O) (2), [Mn3(5-Me-sal)4(py)4(H2O)2] n ·n(MeOH) (3), and [Mn3(3-Me-sal)4(4-Me-py)4] n (4) and the one-dimensional (1D) coordination polymer {[Mn2(4-Me-sal)2(4-Me-py)2(H2O)2(MeOH)2][Mn(4-Me-sal)2(4-Me-py)2]} n (5) have been synthesized, where x-Me-salH2 = x-methyl salicylic acid (x = 3, 4, 5), py = pyridine, and 4-Me-py = 4-methyl-pyridine. The 3D frameworks of compounds 1−4 can be described as diamondoid networks. Magnetic studies show that weak MnII−MnIII antiferromagnetic interactions (in the range of −0.55 to −0.22 K) mediated by syn-anti carboxylate bridges are present in all compounds. While 5 remains paramagnetic down to 1.8 K, the 3D networks exhibit long-range ferrimagnetic ordering below 7.4 K for 1, 4.6 K for 2, 3.0 K for 3, and 7.7 K for 4. The decrease of the critical temperature reflects the increase of the coordination number around the Mn(II) site from four in 1, five in 2, and six in 3 that lower the bond strength and the magnetic interactions. This result also reinforces the hypothesis that the structures of 1 and 4 are similar as suggested by the X-ray analysis.

Self-assembly of heterometallic LnIII–CoIIcoordination polymers: syntheses, structures, and magnetic studies

“…As a result, in the past two decades, a huge number of one-, two-, and three-dimensional CPs, exhibiting novel properties, have been reported, illustrating the explosion of activity in this field. [5][6][7][8][9][10][11][12][13][14][15][16][17] The synthetic strategy for the construction of multi-dimensional CPs has two important aspects: suitable inorganic (metal centers) and organic (ligands) building blocks. Thereinto, lanthanides have become increasingly popular in synthesizing CPs, due to their coordination nature, allowing much more structural styles [18][19][20][21][22][23] than the fixed coordination models for the majority of d-metal ions.…”

Spin-Canting Magnetization in an Unusual Co4 Cluster-Based Layer Compound from a 2,3-Dihydroxyquinoxaline Ligand

“…In studies of the magnetic properties of magnetic frameworks, the main advantage is the availability of numerous types of structures and topologies, in which a large magnetic anisotropy is produced from a single ion and/or there is a situation where structural distortion can result in the production of multifunctional materials with magnetic properties. Several different strategies have been employed, in attempts to achieve such magnetic entities. , However, the design and synthesis of such molecular materials with predictable magnetic properties continues to remain a challenging task because structural factors governing exchange coupling between paramagnetic centers are complex and elusive.…”

Magnetic coordination clusters and networks: synthesis and topological description

“…The two-dimensional magnetic network exhibits spin orientation behaviour at low temperature, which has been confirmed from heat-capacity measurements. (Mukherjee et al 2009). The topology of compounds 12-15 can be described as diamondoid networks (figure 12).…”