Utilization of a ligand containing 2,2′-bipyridyl and tetrazolate groups to construct a 2D Co(ii) coordination polymer: spin canting and metamagnetism

Abstract

The use of anions of 6,6'-bis(1H-tetrazol-5-yl)-2,2'-bipyridine (H2btzbp) as chelating ligands in preparing a coordination polymer is described. The synthesis, X-ray crystal structure and magnetic properties of a new Co(II) coordination polymer, [Co(btzbp)]n (1), are reported. The in situ [2 + 3] cycloaddition reaction of 6,6'-dicyano-2,2'-bipyridine with sodium azide in the presence of Co(ClO4)2 under hydrothermal conditions afforded compound 1. Structural characterization revealed that 1 features a distorted two-dimensional (2D) grid layer generated by both tetrazolate and 2,2'-bipyridyl bridges of the btzbp(2-) ligand. Variable temperature and field magnetic susceptibility measurements indicate that compound 1 exhibits spin canting with T(N) = 4.0 K and metamagnetism with H(c) = 300 G.

Two New Three-Dimensional Pillared-Layer Co(II) and Cu(II) Frameworks Involving a [M2(EO-N3)2] Motif from a Semi-Flexible N-Donor Ligand, 5,5′-Bipyrimidin: Syntheses, Structures and Magnetic Properties

“…Moreover, the distortion of the octahedral Co(II) site might display considerable anisotropy, which also contributes to the spin canting in 1. Some similar results have been reported for other Co(II) compounds [29][30][31][32]. indicative of the spontaneous, ferromagnetic-like magnetization, due to spin canting.…”

“…Moreover, the distortion of the octahedral Co(II) site might display considerable anisotropy, which also contributes to the spin canting in 1. Some similar results have been reported for other Co(II) compounds [29][30][31][32]. To investigate low-temperature magnetic behavior, zero-field-cooled (ZFC) and field-cooled (FC) magnetizations were performed for 1 at 10 Oe in the range of 2.0-40 K ( Figure S5).…”

Utilization of mixed ligands to construct two new coordination polymers: Syntheses, structures and properties

“…S1). The Co-N distance is 2.1101(18) Å, and Co-O distances fall in the range 2.0257(17)-2.0583(16) Å, which are comparable to the reported compound [Co(btzbp)] n (btzbp ¼6,6 0 -dicyano-2,2 0 -bipyridine) [53]. In compound 1, the binuclear cobalt units are linked by four syn,syn-μ 2 -η 1 :η 1 :η 0 :η 0 carboxyl groups with Co Á Á Á Co distance of 2.90 Å.…”

“…The large negative Weiss constant further confirms the antiferromagnetic behavior. Such antiferromagnetic coupling has been observed before for some cobalt-containing coordination polymers [47,52,53,61].…”

A Three-Dimensional Nickel(II) Framework from a Semi-Flexible Bipyrimidyl Ligand Showing Weak Ferromagnetic Behavior

“…Spin canting is generally attributed to the existence of (1) antisymmetric superexchange interactions (Dzyaloshinsky−Moriya interaction) and/or (2) the appropriate single-ion magnetic anisotropy of metal ions. These two factors could induce a different preferential direction in the magnetic moments for metal ions that are located in different sublattices [34,35]. The antisymmetric exchange coupling would be predicted to disappear in the presence of an inversion center between adjacent spin centers [35].…”