Single-Molecule Magnetism Properties of the First Strontium-Manganese Cluster [SrMn(14)O(11)(OMe)(3)(O(2)CPh)(18)(MeCn)(2)]
The preparation and properties of the first strontium-manganese molecular complex are described. The reaction of (NBu{sup n}{sub 4})[Mn402(02CPh)9(H20)] (4Mn{sup III}) with Sr(ClO{sub 4}){sub 2} in MeCN/MeOH led to the isolation of [SrMn{sub 14}O{sub 11}-(OMe)3(02CPh){sub 18}(MeCN)2] (1; 13Mn{sup III}, Mn{sup II}). The structure of 1 consists of two [Mn{sub 4}0{sub 3}(OMe)] cubane units attached to a central, near-planar, trinuclear [Mn{sub 3}O{sub 4}] unit, to which are also attached a Mn and a Sr above the plane and a [Mn{sub 2}O(OMe)] rhomb below the plane. Peripheral ligation is provided by 18 bridging benzoate and two terminal MeCN groups. Variable-temperature and -field dc magnetization (M) data were collected in the 1.8-10 K and 0.1-4.0 T ranges and fit by matrix diagonalization methods to give S = 9/2, D = -0.50(5) cm{sup -1}, and g = 1.88(10), where S is the ground-state spin and D is the axial zero-field splitting parameter. Magnetization versus dc field sweeps at various temperatures and scan rates exhibited hysteresis loops, confirming 1 to be a new single-molecule magnet. Because complex 1 is the initial molecular example of intimately associated Mn and Sr atoms, Sr EXAFS studies have been performed for the first time on a synthetic Sr-containing molecule. This has also allowed comparisons with the EXAFS data on the Sr-substituted water oxidizing complex (WOC) of Photosystem II (PS II), which contains a SrMn{sub 4} complex.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 953619
- Report Number(s):
- SLAC-REPRINT-2009-264; INOCAJ; TRN: US201002%%1447
- Journal Information:
- Inorg. Chem.47:1940,2008, Vol. 47; ISSN 0020-1669
- Country of Publication:
- United States
- Language:
- English
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