A Chain of Vertex-Sharing {CoIII2CoII2}n Squares with Single-Ion Magnet Behavior

A new mixed-valence one-dimensional coordination polymer of formula {[CoII(MeOH)2][(μ-NC)2CoIII(dmphen)(CN)2]2}n·2nH2O (1) was obtained by reacting the Ph4P[CoII(dmphen)(CN)3] metalloligand (dmphen = 2,9-dimethyl-1,10-phenanthroline and Ph4P+ tetraphenylphosphonium ion) with cobalt(II) acetate tetrahydrate. The structural analysis shows formation a neutral 4,2-ribbon-like chain vertex-sharing cyanido-bridged {CoIII2CoII2} squares in which underwent an oxidation process reorganization to form {CoIII(dmphen)(CN)4}− linkers that coordinate [CoII(MeOH)2]2+ units through single cyanido ligands. Both Co(III) cations are six-coordinated distorted octahedral environments. shortest intrachain distance between paramagnetic ions is 7.36 Å, value shorter than interchain one (10.36 Å). Variable-temperature (1.9–300 K) static (dc) magnetic measurements for 1 indicate occurrence magnetically isolated high-spin D +67.0 cm−1. Dynamic alternating current (ac) 2.0–13 K reveal exhibits slow relaxation under non-zero applied dc fields, being thus example field-induced SIM easy-plane anisotropy. Theoretical calculations CASSCF/NEVPT2 on support results from magnetometry. magnetization occurs ground state external fields two-phonon Raman intra-Kramers mechanism.