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 btzbp²⁻ 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.