Cobalt and copper pyridylmethylphosphonates with two- and three-dimensional structures and field-induced magnetic transitions

Abstract

Two novel metal pyridylmethylphosphonates, namely, [Co(4-pmp)] (1) and [Cu(4-pmp)(H2O)] (2), (4-pmpH2 = 4-pyridylmethylphosphonic acid), have been hydrothermally synthesized and characterized by X-ray diffraction, infrared spectroscopy, elemental analysis, and thermogravimetric analysis. In compound 1, each {PO3C} tetrahedron is corner-shared with three {CoNO3} tetrahedra and vice versa, thus forming a one-dimensional (1-D) inorganic chain along the a axis containing 8-membered rings of [(Co-O-P-O)2]. The inorganic chains are further connected by a 4-pmp(2-) ligand, generating a 2-D layered structure. Compound 2 displays a three-dimensional (3-D) framework structure, in which the inorganic layers are pillared by the pyridyl groups of the ligand, generating a 3-D pillared-layered structure. The magnetic properties of 1 and 2 have been studied. Compounds 1 and 2 behave as metamagnets at low temperature. The critical fields are about 70 kOe for 1 and 47 kOe for 2 at 1.8 K.

Cobalt(II)‐dianthracene Frameworks: Assembly, Exfoliation and Properties

“…Assuming that Co‐PO 3 chain structure in MDAF‐3 was maintained after phase transitions, the susceptibility data of MDAF‐3‐120 and MDAF‐3‐230 can be analyzed similarly resulting in parameters J =−0.85 cm −1 and g =2.31 for MDAF‐3‐120 , and J =−1.37 cm −1 and g =2.48 for MDAF‐3‐230 (Figure 6b, 6c). The M vs. H curve of MDAF‐3‐230 revealed a pronounced S ‐shape at 2 K, indicating a metamagnetic behavior, similar to a few other cobalt phosphonates in which the Co(II) ions are connected by O−P−O units into layers or chains [43–45] . The critical field is 17.5 kOe.…”

“…The M vs. H curve of MDAF-3-230 revealed a pronounced S-shape at 2 K, indicating a metamagnetic behavior, similar to a few other cobalt phosphonates in which the Co(II) ions are connected by OÀ PÀ O units into layers or chains. [43][44][45] The critical field is 17.5 kOe. The ac magnetic susceptibility measurements in the temperature range of 2.0-25.0 K revealed a round peak at ca.…”

Construction of Novel Coordination Polymers Based on Pyrazole Carboxylic Acid and Doping for Enhancing the Photocatalytic Property Under Visible Light

“…Recently, the rational design and synthesis of functional coordination polymers (CPs) have received considerable attention due to their diverse structures and potential applications in sorption, catalysis, luminescent materials, magnetism, proton conductivity, etc. − In these potential applications, some CPs have shown photocatalytic performance in reducing carbon dioxide, splitting water, degrading environmental pollutants, etc. − because these functional CPs exhibit an efficient separation of photogenerated charge carriers. Accordingly, a lot of interest has been paid to developing novel CPs photocatalytic catalysts through varying organic bridging linker structures and metal ions with different electronic configurations. ,− …”