- [ReF6]2-: A robust module for the design of molecule-based magnetic materials
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A facile synthesis of the [ReF6]2- ion and its use as a building block to synthesize magnetic systems are reported. Using dc and ac magnetic susceptibility measurements, INS and EPR spectroscopies, the magnetic properties of the isolated [ReF6]2- unit in (PPh4)2[ReF6]?2H2O (1) have been fully studied including the slow relaxation of the magnetization observed below ca. 4 K. This slow dynamic is preserved for the one-dimensional coordination polymer [Zn(viz)4(ReF 6)]1 (2, viz=1-vinylimidazole), demonstrating the irrelevance of low symmetry for such magnetization dynamics in systems with easy-plane-type anisotropy. The ability of fluoride to mediate significant exchange interactions is exemplified by the isostructural [Ni(viz)4(ReF6)]1 (3) analogue in which the ferromagnetic NiII-ReIV interaction (+10.8 cm-1) dwarfs the coupling present in related cyanide-bridged systems. These results reveal [ReF6]2- to be an unique new module for the design of molecule-based magnetic materials.
- Pedersen, Kasper S.,Sigrist, Marc,Sorensen, Mikkel A.,Barra, Anne-Laure,Weyhermuller, Thomas,Piligkos, Stergios,Thuesen, Christian Aa.,Vinum, Morten G.,Mutka, Hannu,Weihe, Hogni,Clerac, Rodolphe,Bendix, Jesper
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- Zwitterionic stabilization of a reactive cobalt tris-isocyanide monoanion by cation coordination
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A break with tradition: The cation, [Ph3P=N=PPh 3]+ ([PPN]+), was found to provide a stabilizing η2-arene interaction to the coordinatively unsaturated, tris-isocyanide monoanion, [Co(CNArMes2) 3]-(ArMes2=2,6-(2,4,6-Me3C 6H2)C6H3); Co=purple, N=light purple, and P=orange). The resulting zwitterion is a source of [Co(CNAr Mes2)3]- anions, performing nucleophilic additions, carbon-element bond activations, and multistep decarbonylations.
- Carpenter, Alex E.,Margulieux, Grant W.,Millard, Matthew D.,Moore, Curtis E.,Weidemann, Nils,Rheingold, Arnold L.,Figueroa, Joshua S.
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supporting information
p. 9412 - 9416
(2012/11/07)
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- Sequestered alkyllithiums: Why phenyllithium alone is suitable for betaine-ylide generation
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The key step in the trans-selective modification of the Wittig reaction is the α-lithiation of the lithium bromide coordinated ylide - aldehyde adduct (the so-called "P-betaine"). Only phenyllithium effects this deprotonation rapidly and cleanly. Alkyllithiums (in particular, butyl-, sec-butyl-, and tert-butyllithium) react only sluggishly and incompletely, being tied up in very stable mixed aggregates with the lithium alkoxide part of the betaines.
- Wang, Qian,Deredas, Dariusz,Huynh, Cyril,Schlosser, Manfred
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p. 570 - 574
(2007/10/03)
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