Azido-cobalt(II) coordination polymers exhibiting slow magnetic relaxation and metamagnetic transition. (15th September 2019) - Mautner, Franz A.
Graphical abstract: Two 1D CPs of doubly bridged-azido-cobalt(II) complexes catena -[Co(2, 6-lutidine- N -oxide)(μ1, 1 -N3 )2 ] (1 ) and catena -{[Co(μ1, 1 -N3 )2 (H2 O)2 ](3-picoline- N -oxide)2 } (2 ) were synthesized, structurally and magnetically characterized. The SCM behavior of the complexes was verified. Abstract: Two coordination polymers of mono-dimensional doubly bridged-azido-cobalt(II) complexes catena -[Co(2, 6-lutidine- N -oxide)(μ1, 1 -N3 )2 ] (1 ) and catena -{[Co(μ1, 1 -N3 )2 (H2 O)2 ](3-picoline- N -oxide)2 } (2 ), where 2, 6-lutidine- N -oxide = 2, 6-dimethylpyridine- N -oxide and 3-picoline- N -oxide = 3-methylpyridine- N -oxide, were synthesized, and structurally characterized by single crystal X-ray crystallography. The Co(II) cations in complexes1 and2 are penta- and hexa-coordinate, respectively with four μ1, 1 -bridging azido groups and a terminal 2, 6-lutidine- N -oxide molecule in1 or two trans aqua molecules in2 . Magnetic relaxations in the zero field are consistent with single chain magnetic behavior (SCM) and the ac susceptibility measurements revealed that the weak ferromagnetic exchanges in the two complexes are associated with slow relaxation of magnetization. Complex2 exhibits metamagnetic transition with an antiferromagnetic phase transition at 12 K at the applied field of 200 Oe.