Heterometallic linear tetramers [Mn(5-R-saltmen)Ni(pao)(bpy) 2]2-(ClO4)4 (5-R-saltmen 2- = N,N′-1,1,2,2-tetramethylethylene bis(5-R- salicylideneiminate); pao- = pyridine-2-aldoximate; bpy = 2,2′-bipyridine, R = H, 1; Cl, 2; Br, 3; MeO, 4) have been synthesized and structurally characterized. These compounds exhibit a [NiII-NO- MnIII-(O)2-MnIII-ON-NiII] skeleton where -ON- is an oximate bridge between MnIII and NII ions and -(O)2- is a bi-phenolate bridge between MnIII ions. These tetramers can be seen as oligomeric units of the heterometallic Mn III2-NII chain observed in a family of single-chain magnets (Clérac, R.; Miyasaka, H.; Yamashita, M.; Coulon, C. J. Am. Chem. Soc. 2002, 124, 12837. Miyasaka, H.; Clérac, R.; Mizushima, K.; Sugiura, K.; Yamashita, M.; Wernsdorfer, W.; Coulon, C. Inorg. Chem. 2003, 42, 8203.). Magnetic measurements on these tetramers confirm the nature of the magnetic interactions reported for the MnIII2-Ni II chains: a strong antiferromagnetic MnIII/Ni II coupling via the oximate bridge (JNi-Mn ranges from -23.7 to -26.1 K) and a weak ferromagnetic MnIII/MnIII coupling through the bi-phenolate bridge (JMn-Mn ranges from +0.4 to +0.9 K). These magnetic interactions lead to tetramers with an S = 2 ground state.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry