Coordination Polymers Containing Manganese(II)-Azido Layers Connected by Dipyridyl-tetrazine and 4,4′-Azobis(pyridine) Linkers

Two new polynuclear manganese­(II) complexes [Mn­(dptz)­(N3)2]n (1) and [Mn­(azpy)­(N3)2]n (2) (where dptz = dipyridyl-tetrazine and azpy
= 4,4′-azobis­(pyridine)) have been synthesized by self-assembly
of the ligand azide, together with dptz and azpy as secondary spacers.
The compounds are characterized by single-crystal X-ray diffraction
analyses and variable-temperature magnetic measurements. The structural
analyses reveal that in complex 1, which is the first
reported Mn­(II) complex with the ligand dptz, two μ1,3 bridging azides connect neighboring manganese ions in a zigzag manner
to generate a neutral two-dimensional (2D) sheet which is further
connected by the dptz ligands to form a three-dimensional (3D) framework.
By contrast, complex 2 contains dimeric [Mn2(μ1,1-N3)2]2+ fragments
linked to four identical motifs by means of four single μ1,3-N3 bridges, that generates a neutral 2D MnII–azide sheet which is further interconnected by azpy
ligands to neighboring manganese ions forming an unprecedented 3D
network. Variable-temperature (2–300 K) magnetic susceptibility
measurements show the presence of predominantly antiferromagnetic
coupling for both complexes that has been reproduced with a regular
antiferromagnetic S = 5/2 chain (J) with interchain interactions (j) modeled with
the molecular field approximation with J = −7.1
cm–1 and j′ = −0.8
cm–1 for 1 and J =
−4.2 cm–1 and j′
= 0.1 cm–1 for 2.