New Cobalt(II) Field‐Induced Single‐Molecule Magnet and the First Example of a Cobalt(III) Complex with Tridentate Binding of a Deprotonated 4‐Amino‐3, 5‐bis(pyridin‐2‐yl)‐1, 2, 4‐Triazole Ligand. Issue 2 (27th December 2018)

• Record Type: Journal Article
• Authors: Váhovská, Lucia; Bukrynov, Oleksandr; Potočňák, Ivan; Čižmár, Erik; Kliuikov, Andrii; Vitushkina, Svitlana; Dušek, Michal; Herchel, Radovan
• Is Part Of: European journal of inorganic chemistry. Issue 2(2019)
• Page Start: 250
• Page End: 261
• Publication Date: 2018-12-27
• Subjects: Cobalt -- Magnetic properties -- Structure elucidation -- Azides; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201801225
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : From Co(NO3 )2 · 6H2 O ‐ NaN3 ‐ abpt reaction system, a mononuclear complex [Co(abpt)2 (N3 )2 ] (abpt = 4‐amino‐3, 5‐bis(pyridin‐2‐yl)‐1, 2, 4‐triazole) (1 ) and a dinuclear complex [Co2 (abpt)(µ‐abpt‐H)2 (N3 )4 ]· 1.12H2 O (2 ) were obtained. The presence of neutral abpt, as well as azido ligands was proved by IR spectroscopy. X‐ray crystallography shows that 1 is a molecular Co II complex with two azido ligands coordinated in trans ‐positions, while 2 is a dinuclear Co III complex bridged by two abpt‐H ligands. π–π stacking interactions between pyridyl rings of abpt and N‐H··· N and C‐H··· N hydrogen bonds in 1 and 2 stabilize their structures by creating a 3D supramolecular network. The analysis of the magnetic properties of 1 revealed negative zero‐field splitting parameter D = –24.1 cm –1 supported also by CASSCF/NEVPT2 and CASSCF/CASPT2 theoretical calculations. The X‐band electron paramagnetic resonance also gives an evidence for a strong rhombic character of the anisotropy. The investigation of the ac susceptibility measurements identified 1 as a field‐induced single‐molecule magnet, in which direct, Raman and Orbach relaxation processes are present. Abstract : Two new Co complexes, [Co(abpt)2 (N3 )2 ] (1 ) and [Co2 (abpt)(µ‐abpt‐H)2 (N3 )4 ]· 1.12H2 O (2 ) (abpt = 4‐amino‐3, 5‐bis(pyridin‐2‐yl)‐1, 2, 4‐triazole), were synthesized from one reaction system. Complex 1 is a mononuclear cobalt(II) field‐induced single‐molecule magnet, while 2 is a dinuclear cobalt(III) complex with the tridentate abpt‐H ligand.