Syntheses, crystal structures and magnetic properties of two mixed-valence Co(iii)Co(ii) compounds derived from Schiff base ligands: field-supported single-ion-magnet behavior with easy-plane anisotropy

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 46; no. 38; pp. 13135 - 13144
• Main Authors: Mandal, Shuvankar, Mondal, Suraj, Rajnák, Cyril, Titiš, Ján, Boča, Roman, Mohanta, Sasankasekhar
• Format: Journal Article
• Language: English
• Published: England 14.10.2017
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c7dt02455j

Two μ-phenoxo-μ -azide dinuclear Co Co complexes [Co (N ) L (μ -N )Co (N )]·MeOH (1) and [Co (N ) L (μ -N )Co (N )]·MeOH (2) (HL and HL are two Schiff base ligands having N O-N O compartments) both possess one hexacoordinate Co(iii) and one pentacoordinate Co(ii) center. DC magnetic susceptibility and magnetization measurements show an appreciable amount of positive magnetic anisotropy (D/hc∼ 40 cm ) that is also confirmed by ab initio CASSCF calculations. AC susceptibility measurements of 1 reveal that it exhibits a slow magnetic relaxation with two relaxation channels. The external magnetic field supports the low-frequency (LF) channel that escapes on heating more progressively than the high-frequency (HF) branch. The relaxation time is as slow as τ = 255 ms at T = 1.9 K and B = 0.6 T, where the LF mole fraction is 69%. The complex 2 also displays similar field-supported slow magnetic relaxation with two relaxation channels.