Weak M(II)-Azide-4,4‘-Bipy Ferromagnets Based on Unusual Diamondoid (M = Mn) and 2D Arrays (M = Co, Ni)

Abstract

Four compounds of general formula [M(4,4'bipy)(N(3))2](n) (M = Mn (1), Zn (2), Co (3), Ni (4)) have been synthesized and magnetostructurally characterized by means of X-ray diffraction analysis, IR and ESR spectroscopies, and measurements of the magnetic susceptibility and magnetization. Compound 1 (C(10)H(8)N(8)Mn) crystallizes in the tetragonal P4(3)2(1)2 space group, Z = 4, with a = 8.229(2), b = 8.229(2), and c = 16.915(2) A. It exhibits an acentric 3D structure where Mn(II) ions are linked through EE-azide groups resulting in a diamondoid network. The 4,4'bipy ligands are coordinated on the axial positions of the octahedral spheres reinforcing the intermetallic connections. Weak ferromagnetism arising from spin canting is observed for compound 1. Compounds 2, 3, and 4 are proposed to be isomorphous and would consist of a 2D array where alternating EO + EE/EO + EE/EO + EO azide-chains are linked by 4,4'bipy ligands resulting in pi-pi stacked pyridyl-columns. The azido ligand dispositions in compounds 3 and 4 make possible systems of type -AF-AF-F-, which would give rise to a topological ferromagnetic behavior.

Synthesis, spectroscopic characterization, X-ray structure, and DFT calculations of [Cu(tppz)(SCN)2]

“…Azide-and thiocyanate ions are frequently used in combination with polydentated organic ligands for the preparation of coordination compounds of various dimensionalities [3,[11][12][13][14][15]. 2,3,5,6-Tetra-(2-pyridyl)pyrazine (tppz), originally synthesized by Goodwin and Lions in 1959 [16], belongs to such ligands.…”

Self-assembly of iron TCPP (meso-tetra(4-carboxyphenyl)porphyrin) into a chiral 2D coordination polymer

“…Some of these combinations are specially remarkable as they include fullerene [26], silica [27] and 4,4´-bipyridine [28][29]. During the last years, our research has been focused on the preparation of coordination polymers with increasing dimensionality with a variety of metal-ligand combinations, and we have prepared several high dimensional structures with 4,4´-bipyridine, including interpenetrated networks [30][31][32][33][34][35]. In this sense, it is worth mentioning that, when combining an O-donor ligand like TCPP, with a N-donor one, like 4,4´-bipyridine, the Pearson acidity is one of the leading forces to be considered in the extension of the structure, as it is in relationship with the affinity of the metal centre, which is influenced by its oxidation state.…”

Thermodynamics of spin-1∕2antiferromagnet-antiferromagnet-ferromagnet and ferromagnet-ferromagnet-antiferromagnet trimerized quantum Heisenberg chains

“…The examples of AF-AF-F chains are [M n(L) 2 (N 3 ) 2 ] n with spin S = 5/2 [5], [M (4, 4 ′ bipy)(N 3 ) 2 ] n with M = Co (S = 3/2) and N i (S = 1) [6], and [M n(N 3 ) 2 (bpee)] n with S = 5/2 [7].…”