Synthesis, structure and magnetic properties of dinuclear cobalt-tetraoxolene complexes with bidentate terminal ligands
authors Jana, NC; Brandao, P; Mathoniere, C; Panja, A
nationality International
journal POLYHEDRON
author keywords 2,5-Dihydroxy-1,4-benzoquinonate ligand; Dinuclear cobalt(II)/cobalt(III) complexes; Crystal structures; Cyclic voltammetry; Magnetic study
keywords INTRAMOLECULAR ELECTRON-TRANSFER; VALENCE TAUTOMERIC TRANSITIONS; SPIN-CROSSOVER; MOLECULAR SPINTRONICS; THERMAL HYSTERESIS; ROOM-TEMPERATURE; METAL-COMPLEXES; IRON COMPLEXES; MIXED-VALENCE; TRIS(2-PYRIDYLMETHYL)AMINE
abstract The design of molecule-based systems with tuneable optical and/or magnetic properties has attracted considerable attention because of their potential applications in high-performance molecule-based electronic devices, switches, sensors and displays. In this regard, a large number of valence tautomeric tetraoxolene-bridged dinuclear cobalt complexes with tetradentate ancillary ligands have been reported, but none of these complexes contained a bidentate terminal ligand. In order to increase the scope in this field, the present report describes the synthesis, structures, electrochemical and magnetic studies of two dinuclear cobalt-tetraoxolene complexes, [Co-2(dhbq)(bpy)(4)](PF6)(3) (1(PF6)(3)) and [Co-2(dhbq)(bpa)(4)] (PF6)(3)center dot 6H(2)O (2(PF6)(3)center dot 6H(2)O), where H(2)dhbq is 2,5-dihydroxy-1,4-benzoquinone, with the bidentate terminal ligands 2,2'-bipyridine (bpy) and 2,2'-bipyridyl amine (bpa), respectively. An X-ray diffraction study reveals that the dianionic form of the redox active tetraoxolene ligand bridges the metal centers in these complexes, and one metal center is in the high spin cobalt(II) state while the other one is in the low spin cobalt(III) state. The present report will increase knowledge on the synthesis of such systems using bidentate terminal ligands. Variable temperature magnetic susceptibility measurements show no indication for valence tautomerism (VT) in either complex. Further attempts could be made to synthesize similar complexes from different solvents and/or using different counter ions to check whether such variations can bring VT in these systems. (C) 2018 Elsevier Ltd. All rights reserved.
publisher PERGAMON-ELSEVIER SCIENCE LTD
issn 0277-5387
year published 2018
volume 144
beginning page 152
ending page 157
digital object identifier (doi) 10.1016/j.poly.2017.12.038
web of science category Chemistry, Inorganic & Nuclear; Crystallography
subject category Chemistry; Crystallography
unique article identifier WOS:000428829400020
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journal analysis (jcr 2019):
journal impact factor 2.343
5 year journal impact factor 1.894
category normalized journal impact factor percentile 60.363
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