Single‐Ion Magnetic Behavior in CoII–CoIII Mixed‐Valence Dinuclear and Pseudodinuclear Complexes. Issue 19 (23rd May 2017)

• Record Type: Journal Article
• Authors: Manna, Soumen; Bhunia, Apurba; Mistri, Soumen; Vallejo, Julia; Zangrando, Ennio; Puschmann, Horst; Cano, Joan; Manna, Subal Chandra
• Is Part Of: European journal of inorganic chemistry. Issue 19(2017)
• Page Start: 2585
• Page End: 2594
• Publication Date: 2017-05-23
• Subjects: Cobalt -- Structure elucidation -- Magnetic properties -- Single‐ion magnets; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201700046
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : Two Co II –Co III mixed‐valance complexes of molecular formulas [Co2 (H2 L)2 (H2 O)2 ][Co2 (H2 L)2 (H2 O)( m ‐phth)]· 8(H2 O) {1 ; H2 L 2– = 2‐[(2‐hydroxy‐3‐methoxybenzylidene)amino]‐2‐(hydroxymethyl)propane‐1, 3‐diolato, m ‐phth = 1, 3‐benzenedicarboxylate} and [Co4 (H2 L)4 (H2 O)2 (ppda)]· 2(dmf)· 3.2(H2 O) {2 ; ppda = 1, 4‐phenylenediacrylate; dmf = N, N ‐dimethylformamide} were synthesized and characterized by single‐crystal X‐ray diffraction and magnetic studies at low temperature. The structural determination reveals that1 is composed of dinuclear ion pairs, namely, a cationic [Co2 (H2 L)2 (H2 O)2 ] + (1 + ) and an anionic [Co2 (H2 L)2 (H2 O)( m ‐phth)] – (1 – ) unit. In each of these ions, the Co II and Co III centers present distorted octahedral geometries. Compound2 is a centrosymmetric tetranuclear complex comprising two symmetry‐related dinuclear Co II –Co III units bridged by ppda anions. Alternating current/direct current (ac/dc) magnetic studies revealed that the individual Co II –Co III unit exhibits field‐induced slow magnetic relaxation consistent with single‐ion magnet (SIM) behavior. Ab initio NEVPT2 calculations confirm large zero‐field splitting (zfs) from a first‐order spin–orbit coupling (SOC) in both complexes ( D = –62.4, –95.8, and –101.9 cm –1 and E/D = 0.219, 0.216, and 0.234 for1 +, 1 –, and2, respectively). Abstract : Two Co II –Co III mixed‐valance complexes are synthesized and characterized by single‐crystal X‐ray diffraction and magnetic studies at low temperature. The individual Co II –Co III units exhibit field‐induced slow magnetic relaxation consistent with single‐ion magnet behavior. Ab initio calculations confirm large zero‐field splitting (zfs) from a first‐order spin–orbit coupling in both complexes.