Field-Induced Slow Magnetic Relaxation in Mononuclear Cobalt(II) Complexes Decorated by Macrocyclic Pentaaza Ligands.

Two cobalt(II) complexes [CoL 1 ](OTf) 2 ( 1 , L 1 = 6,6''-di(anilino)-4'-phenyl-2,2':6',2''-terpyridine) and [CoL 2 ](OTf) 2 ·MeOH ( 2 , L 2 = 6,6''-di( N , N -dimethylamino)-4'-phenyl-2,2':6',2''-terpyridine) were synthesized and characterized. Crystal structure analyses showed that the spin carries were coordinated by five N atoms from the neutral pentaaza ligands, forming distorted trigonal bipyramidal coordination environments. Ab initio calculations revealed large easy-axial anisotropy in complexes 1 and 2 . Magnetic measurements suggest that complexes 1 and 2 are field-induced single-molecule magnets, whose relaxations are mainly predominated by Raman and direct processes.