Tetranuclear Ni(ii) and Co(ii) Schiff-base complexes with an M4O6 defective dicubane-like core: zero-field SMM behavior in the cobalt analogue. (8th September 2017)

• Record Type: Journal Article
• Authors: Nemec, Ivan; Herchel, Radovan; Machata, Marek; Trávníček, Zdeněk
• Is Part Of: New journal of chemistry. Volume 41:Number 19(2017)
• Page Start: 11258
• Page End: 11267
• Publication Date: 2017-09-08
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c7nj02281f
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Two tetranuclear Ni4 and Co4 complexes were prepared and characterized. Their magnetic properties were thoroughly studied and it was revealed that the Co4 compound behaves as a zero-field single-molecule magnet. Abstract : Two isostructural tetranuclear M(ii )4 complexes with the general formula [M4 (L)4 (CH3 OH)2 ] were prepared by the reaction of M(CH3 COO)2 ·4H2 O and H2 L in the presence of Pr3 N (M = Ni in1, Co in2, H2 L = 2-{( E )-[(2-hydroxyphenyl)imino]methyl}phenol, Pr3 N = tripropylamine). The crystal structure of1 was determined by single-crystal X-ray diffraction and it was revealed that it possesses the defective dicubane {Ni4 O6 } 2− core with two penta- and two hexacoordinate Ni atoms. The isostructurality of both complexes was confirmed by powder X-ray diffraction measurements. The analysis of the static magnetic data revealed that the prevailing antiferromagnetic interaction leads to the diamagnetic ground state in1, whereas the ferromagnetic interactions dominate in2 . The analysis of magnetic data was supported by broken-symmetry DFT and CASSCF/NEVPT2 calculations, where the latter disclosed large magnetic anisotropy in both compounds. Moreover, the measurements of ac susceptibility in the zero-applied magnetic field confirmed the presence of slow-relaxation of magnetization in2 and thus, this compound behaves as a single-molecule magnet.