Synthesis and magnetic properties of one-dimensional ferro- and ferrimagnetic chains made up of an alternating array of 1,3-bis( N- tert-butyl- N-oxyamino)benzene derivatives and Mn(II)(hfac) 2

• Published in: Coordination chemistry reviews 2000-03, Vol.198 (1), p.219-229
• Main Authors: Inoue, Katsuya, Iwahori, Fumiyasu, Markosyan, Ashot S, Iwamura, Hiizu
• Format: Article
• Language: English
• Subjects: Low dimensional magnet; Manganese complex; Molecular based magnet; Triplet organic radical
• ISSN: 0010-8545; 1873-3840
• DOI: 10.1016/S0010-8545(99)00225-8

Bis(hexafluoroacetylacetonato) manganese(II), Mn(hfac) 2, reacts with the bisnitroxide radicals, 5- R-1,3-bis( N- tert-butyl- N-oxyamino)benzene ( 1 R) (R=H, Cl and Br), yielding one-dimensional (1-D) polymeric complexes of formula [Mn(hfac) 2 1 R] n . X-ray analysis of the complexes has shown that they crystallize in the monoclinic space group P2 1/ n. In this structure, the manganese(II) ions and 1 R molecules make up one-dimensional chains with the bisnitroxide radical serving as a bidentate ligand to Mn(II)(hfac) 2. The 1 H complex orders antiferromagnetically at 5.5 K, while the 1 Cl and 1 Br complexes show ferrimagnetic order at 4.8 and 5.3 K, respectively. The intrachain exchange interaction parameters for a model of S=3/2 ferromagnetic chains were found to be, 2 J eff/ k=23±2 K in all the compounds. J eff is the effective magnetic exchange interaction between units of NOMnNO. A change in the sign of the interchain exchange interaction is referred to as the change of the shortest exchange path, from the MnFN( tert-Bu)O ( 1 Cl and 1 Br) to N( tert-Bu)O FN( tert-Bu)O ( 1 H)