Influence of the Electric Charge of Spin Probes on Their Diffusion in Room-Temperature Ionic Liquids

This is the author accepted manuscript. The final version is available from the American Chemical Society via the DOI in this recordThe rotational and translational diffusion of negatively charged and uncharged spin probes in five imidazolium-based room-temperature ionic liquids (RTILs), 1-ethyl-3-methylimidazolium tetrafluoroborate, emimBF4, 1-butyl-3-methylimidazolium tetrafluoroborate, bmimBF4, 1-octyl-3-methylimidazolium tetrafluoroborate, omimBF4, 1-octyl-3-methylimidazolium hexafluorophosphate, omimPF6, and 1-octyl-3-methylimidazolium chloride, omimCl, has been studied by means of electron paramagnetic resonance spectroscopy. Detailed analyses of the spin-Hamiltonian parameters and spin exchange interactions have been carried out. The temperature dependences of the line broadening induced by the electronic dipole-dipole interaction and the electron spin exchange coupling are determined. The translational mobility of spin probes is semiquantitatively characterized and successfully explained in the framework of a hypothesis based on the assumption of polar and unpolar domains within the RTILs

The shortened transition metal-tellurium bonds in organometallic clusters

The shortening of partly multiple M-Te (M = Mn, Fe, Co, Cr or W) bonds is observed for two classes of organometallic compounds: (1) formally electron-deficient species with additional donor-acceptor interaction between Te lone pairs and half-occupied d-orbitals of M; (2) formally electron-saturated species having additional dative interaction between M lone pairs and LUMO of Te. These compounds could be prepared by two main methods: (a) interaction of [CpMn(CO)(2)PhC(O)(-)]Li(+) with Te proceeds via formation of intermediate {[CpMn(CO)(2)](2)Te}(2-) which is further transformed into binuclear complex [CpMn(CO)(2)](2)Te(CH(2)Ph)(2) or into trinuclear ditelluride cluster [CpMn(CO)(2)](3)Te(2) on one hand or to mixed-metal monotelluride clusters [CpMn(CO)(2)](2)TeM(CO)(5) on another hand. (b) treatment of Fe(CO)(5), CpMn(CO)(2)(THF) or Me(4)C(4)Co(CO)(2)I with [PhTeI](4), PhTeI(3) or PhTeI(2)HC = CPhI results in different PhTeI-containing complexes of Fe, Mn or Co. The molecular structures of all new compounds were studied by means of X-ray diffraction analyses and the mechanism of M-Te bond shortening is discussed