24762-44-5Relevant articles and documents
[ReF6]2-: A robust 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
, p. 1351 - 1354 (2014)
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.
Sequestered alkyllithiums: Why phenyllithium alone is suitable for betaine-ylide generation
Wang, Qian,Deredas, Dariusz,Huynh, Cyril,Schlosser, Manfred
, p. 570 - 574 (2007/10/03)
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.