Hydrothermal synthesis, X-ray structure and DFT and magnetic studies of a (H₂SiW₁₂O₄₀)²⁻based one-dimensional linear coordination polymer

Abstract

In this paper, we report the synthesis and characterization of a novel hybrid with an inorganic-organic structure formulated as [[Nd2(L(1))2(L(2))(H2O)7][H2SiW12O40]]n·4H2O (1), in which HL(1) = nicotinic acid and H2L(2) = 2-hydroxynicotinic acid. Interestingly, L(1) and L(2) are generated from an in situ transformation of the original ligand, pyridine-2,3-dicarboxylic acid under hydrothermal conditions. Structural analysis showed that this compound is a one-dimensional linear coordination polymer constructed from a repetition of the Keggin anion as a bidentate bridging ligand and one propeller-like dinuclear neodymium complex. Furthermore, in the packing arrangement, hydrogen bonds and anion-π interactions connect the adjacent chains to extend the structure into a 3D architecture. The magnetic properties of this compound have also been studied by measuring its magnetic susceptibility in the temperature range 1.8-300 K. We also analyzed the coordination ability of the SiW12 Keggin anion in the reported structures up to now. Finally, we have performed a DFT computational study on the noncovalent anion-π interactions between the Keggin anion and the aromatic ligands coordinated to Nd.

Surface-grafted lanthanoid complexes of the tungstosilicate polyanion [SiW12O40]4−: a synthetic, structural and computational investigation

“…POMs themselves can form one-to three-dimensional polymeric structures (Mandic et al, 2013;Ritchie et al, 2008;Streb et al, 2007), while their hybrids can be either covalent POM-based MOFs or supramolecular MOFs (SMOFs). The organic ligand (flexible or rigid), the POM charge and the oxidation state of the metal affect the hybrid structure (Alipour et al, 2016;Mirzaei, Eshtiagh-Hosseini, Alipour et al, 2015;Najafi et al, 2016). Moreover, the reaction conditions, such as temperature, time, pH, solvothermal, reflux, etc., are also very important for the final architecture of either MOFs or SMOFs.…”

K6[P2Mo18O62] as DNase-Mimetic Artificial Nucleases to Promote Extracellular Deoxyribonucleic Acid Degradation in Bacterial Biofilms

“…), which have been discovered over the past 200 years . To date, 10 basic topology structures of POMs (Keggin, Dawson, Silverton, Anderson, Waugh, Lindqvist, Weakley, Standberg, Finke, and Preyssler) have been discovered, with Keggin and Dawson structures being most extensively studied. – Recently, emerging multidisciplinary research in POM chemistry further revealed a series of POM clusters with novel topologies and high-dimensional extended architectures, such as lanthanide-functionalized POMs, – POM-based supramolecular frameworks, POM-based inorganic–organic hybrids, – etc.…”

Selective Adsorption of Hemoglobin in Human Whole Blood with a Nickel Monosubstituted Silicotungstic Acid Hybrid

“…There are weak intermolecular interactions, including hydrogen bonds and anion−π interactions in POMs, due to many oxygen atoms of POMs, which is better for constructing high-dimensional supramolecular architectures . Many ligands can be used to build inorganic–organic hybrid materials, for example, N -heterocyclic carboxylic acids, H 2 PDA (1,10-phenanthroline-2,9-dicarboxylic acid), and pyridine-2,3-dicarboxylic acid (2,3-pydc). − POMs possess a variable structure and favorable physical and chemical properties, such as catalytic, photochemical, and electrochemical activity . For example, Fashapoyeh’s group has reported the first example of hydrogen evolution reactivity of lanthanide-substituted Keggin-type polyoxotungstates under photochemical and electrochemical conditions .…”