Field‐Supported Slow Magnetic Relaxation in Hexacoordinate CoII Complexes with Easy Plane Anisotropy. Issue 11 (23rd March 2017)

• Record Type: Journal Article
• Authors: Rajnák, Cyril; Titiš, Ján; Moncoľ, Ján; Renz, Franz; Boča, Roman
• Is Part Of: European journal of inorganic chemistry. Issue 11(2017)
• Page Start: 1520
• Page End: 1525
• Publication Date: 2017-03-23
• Subjects: Cobalt -- Structure elucidation -- Magnetic properties -- Slow magnetic relaxation -- Single‐molecule magnets; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201601335
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : Two mononuclear cobalt(II) complexes containing four equatorial 4‐benzylpyridine and two axial chlorido and/or thiocyanato ligands {[Co[L]4 X2 ]; X = Cl or NCS} possess easy plane magnetic anisotropy, as determined by magnetic susceptibility and magnetization analyses, and confirmed by ab initio calculations ( D = +106 and +95 cm –1 ). AC susceptibility measurements show a slow magnetic relaxation with two or three relaxation branches. The low‐frequency pathway occurs at about 1–10 Hz, and it disappears progressively upon heating. The high‐frequency mode exists at frequency ranges above 500 Hz. The characteristics of these field‐induced single‐molecule magnets strongly depend upon the applied magnetic field, which causes a prolongation of the low‐frequency relaxation time and a shortening of the high‐frequency one. At 1.0 T and 1.9 K the relaxation time for the low‐frequency pathway is as slow as 756 or 164 ms for X = Cl or X = NCS, respectively. Abstract : Mononuclear cobalt(II) complexes {[Co[L]4 X2 ]; X = Cl or NCS} possess easy plane magnetic anisotropy with large zero‐field‐splitting parameters D . They exhibit a slow magnetic relaxation with two or three relaxation branches. At B = 1.0 T and T = 1.9 K the relaxation time for the low‐frequency pathway is as slow as τ = 756 or 164 ms, for X = Cl or X = NCS, respectively.