High-Nuclearity Manganese and Iron Complexes with the Anionic Ligand Methyl Salicylimidate
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- 作者：Meenal D. Godbole ; Olivier Roubeau ; Allison M. Mills ; Huub Kooijman ; Anthony L. Spek ; Elisabeth Bouwman
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：August 21, 2006
- 年：2006
- 卷：45
- 期：17
- 页码：6713 - 6722
- 全文大小：327K
- 年卷期：v.45,no.17(August 21, 2006)
- ISSN：1520-510X
文摘
The three novel clusters [Mn6O4(OMe)2(OAc)4(Mesalim)4] (3), [Mn8O2(OH)2(OMe)12(OAc)2(Mesalim)4] (4), and[Fe10O4(OMe)14Cl2(Mesalim)6] (5) have been synthesized from a simple bidentate ligand HMesalim (HMesalim =methyl salicylimidate). Starting from the mononuclear complex [Mn(Mesalim)2(OAc)(MeOH)]·MeOH (1), either thehexanuclear complex 3 or the octanuclear complex 4 is obtained after recrystallization, depending upon the reactionconditions and solvents used. Similarly, starting from the purple-colored mononuclear complex [Fe(Mesalim)2Cl](2), the orange-colored decanuclear iron(III) cluster 5 has been obtained upon recrystallization from methanol.Complex 3, which could also be prepared directly from manganese acetate and the ligand, has a face-sharingdouble-cubane [Mn6O6] core, unique in transition metal chemistry. Compounds 4 and 5 are composed of [M3O4]partial cubanes. All complexes belong to a class of oxo-bridged cubic close-packed molecular clusters resemblingthe metal oxide/hydroxide ores. Complex 4 exhibits intramolecular ferromagnetic interactions, as evidenced fromdc magnetic susceptibility studies (1.8-300 K), resulting in a high-spin ground state, probably with ST = 8. Complex4 displays single molecule magnet behavior as indicated by frequency and temperature dependences of its acsusceptibility. An Arrhenius plot gave relatively large experimental activation energy of 36.0 K. The magnetic propertiesof complexes 3 and 5 are dominated by antiferromagnetic interactions leading to zero-spin ground states.