Design and Synthesis of a 4-(2‘-Pyridyl)-1,2,3,5-Dithiadiazolyl Cobalt Complex

Abstract

The 4-(2'-pyridyl)-1,2,3,5-dithiadiazolyl neutral radical 1 has been prepared for use as a spin-bearing bidentate ligand. The coordination of this ligand to bis(hexafluoroacetylacetonato)cobalt affords a thermally stable complex 2. Magnetic susceptibility measurements of the crystalline complex indicate ferromagnetic coupling between the ligand-centered spin and the unpaired electrons of the high-spin Co(II).

Metal-radical coordination complexes of thiazyl and selenazyl ligands

“…The bidentate pyDTDA ligand was coordinated to the Co(hfac) 2 fragment and structural and magnetic properties of the sublimed, crystalline complex ( Fig. 7) were reported (where hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato-) [47]. There are number of points regarding the Co(hfac) 2 (pyDTDA) complex that are worth noting.…”

“…In 2004, Preuss et al reported the first N-coordination complex of a DTDA radical [47]. The 2′-pyridyl-1,2,3,5-dithiadiazolyl radical (pyDTDA) was designed as a chelating ligand, intended to remain paramagnetic, with little disruption to the thiazyl heterocycle upon coordination.…”

“…In this way, bidentate chelating ligands pyDTDA and pymDTDA respectively (Fig. 6), were designed to be paramagnetic analogs of 2,2′-bipyridine and 2,2′-bipyrimidine [47,52]. The pyridyl and pyrimidyl heterocycles can be decorated with groups such as halides and nitriles in order to promote electrostatic contacts in the solid state and manipulate the crystal packing of the complexes.…”

Radical ligand-containing single-molecule magnets

“…The ligand 4-(2 -pyridyl)-1,2,3,5-dithiadiazolyl (pyDTDA) [142], is similar to the aforementioned verdazyl-derived ligands in terms of coordination environment and distribution of electron density on the ligand. Although the ligand composition within the molecule is identical in complexes of the type (pyDTDA)M(hfac) 2 geometries around each metal ion resulted in significantly different crystal packing.…”

Radical–Radical Recognition: Switchable Magnetic Properties and Re-entrant Behavior

“…The pyDTDA ligands are N-coordinated to La(III) in a bidentate fashion (Figure 1), similar to previously reported transition metal coordination complexes of this radical ligand. [16][17][18] In both monoclinic phases (vide infra), the pyDTDA ligands are symmetry-related. Although the symmetry is lowered in the triclinic phase, the coordination geometry does not change dramatically as a function of temperature and, in all phases, it is best described as a sphenocorona, 34 typical of 10-coordinate lanthanide species.…”