52093-25-1Relevant articles and documents
The octanuclear europium cluster [bmpyr]6[Eu8(μ 4-O)(μ3-OH)12(μ2-OTf) 14(μ1-Tf)2](HOTf)1.5 obtained from the ionic liquid [bmpyr][OTf]
Babai, Arash,Mudring, Anja-Verena
, p. 1956 - 1958 (2006)
The octanuclear europium cluster compound [bmpyr]6[Eu 8(μ4-O)(μ3-OH)12(μ 2-OTf)14(μ1-OTf)2](HOTf) 1.5 has been crystallized from the ionic liquid [bmpyr][OTf]. Structural characterization by single crystal X-ray diffraction revealed an Bug cluster unit which is centered by an oxide anion. The Bug-cluster polyhedron can be described as a bicapped octahedron or a triangulated dodecahedron. Each of the triangular faces of the cluster is capped by one μ3-hydroxo group. Fourteen μ2-triflate (CF3SO3 -) anions bridge via oxygen the cluster edges. Together with two μ1-terminal coordinating triflate anions they complete the cluster unit. Six cations from the ionic liquid counterbalance the cluster charge. Additionally, 1.5 HOTf molecules per Bug-cluster unit are incorporated in the crystal structure of the title compound.
TG-DTA study on the lanthanoid trifluoromethanesulfonate complexes
Egashira,Yoshimura,Kanno,Suzuki
, p. 501 - 508 (2008/10/08)
The thermal decomposition of the lanthanoid trifluoromethanesulfonate (triflate) complexes {Ln(CF3SO3)3·9H2O; Ln=La-Lu} was studied by TG and DTA methods. From the endothermic and exothermic data of Ln(CF3SO3)3·9H2O complexes, pyrolysis behavior of the complexes is classified into three groups: 1) La-Nd salts, 2) Sm-Ho salts, 3) Er-Lu salts. It has also shown that all the final decomposition products were found to result in the formation of LnF3.
Metal ion-catalyzed Diels-Alder and hydride transfer reactions. Catalysis of metal ions in the electron-transfer step
Fukuzumi, Shunichi,Ohkubo, Kei,Okamoto, Toshihiko
, p. 14147 - 14155 (2007/10/03)
Rates of Diels - Alder cycloaddition of anthracenes with p-benzoquinone and its derivatives as well as rates of hydride-transfer reactions from 10-methyl-9,10-dihydroacridine to the same series of p-benzoquinones are accelerated significantly in the presence of metal ions in acetonitrile. An extensive comparison of the catalytic effects of metal ions in electron transfer from one-electron reductants (cobalt tetraphenylporphyrin and decamethyrferrocene) to p-benzoquinones with those in the Diels - Alder reactions of the quinones as well as the hydride-transfer reactions has revealed that the catalysis of metal ions in each case is ascribed to the 1:1 and 1:2 complexes formed between the corresponding semiquinone radical anions and metal ions. The transient absorption and ESR spectra of the semiquinone radical anion-metal ion complexes are detected directly in the electron-transfer reduction of p-benzoquinone derivatives in the presence of metal ions. The catalytic reactivities of a variety of metal ions in each reaction are well correlated with the energy splitting values of πg levels because of the complex formation between O2.- andMn+, which are derived from the gzz values of the ESR spectra of the O2.--Mn+ complex.
Characterization of a series of lanthanide amine cage complexes
Smith, Paul H.,Reyes, Zelideth E.,Lee, Chi-Woo,Raymond, Kenneth N.
, p. 4154 - 4165 (2008/10/08)
The preparation and characterization of a series of encapsulated lanthanide amine complexes are discussed. The complexes of Ce, Pr, Eu, and Y with the ligand 1,9-bis(2-aminoethyl)-1,4,6,9,12,14-hexaazacyclohexadecane (referred to as L) have been prepared by using the previously described template approach (using La and Yb) involving the combination of the metal trifluoromethanesulfonate (triflate or trif) salt as the template source, 2 equiv of the tetradentate amine 2,2′,2″-tris(2-aminoethyl)amine (tren), and an excess of the formaldehyde derivative bis(dimethylamino)methane. The reduction potentials of the europium and ytterbium complexes are -0.68 and -1.37 V (vs SCE, in propylene carbonate), respectively, suggesting that this ligand imparts a large stabilization of the +3 oxidation state relative to the +2 state. An analogous lanthanum triflate complex, La(L′)(trif)3 [L′ = bis((2-(bis(2-aminoethyl)amino)ethyl)amino)methane], with one methylene bridge has been prepared and characterized by single-crystal X-ray crystallography. The structure is similar to that of the previously described dibridged complex La(L)(trif)3·CH3CN, and a comparison of these structures suggests possible explanations for the difficulties of obtaining the fully encapsulated lanthanide complex. The complex crystallizes in space group P1 with Z = 2 and a = 9.8448 (13) A?, b = 11.0620 (15) A?, c = 16.8557 (19) A?, α = 73.456 (9)°, β = 73.684 (10)°, and γ = 70.548 (11)°. For 6065 independent data with Fo2 > 3σ(Fo2), full-matrix least-squares refinement with anisotropic thermal parameters for all non-hydrogen atoms (except disordered atoms) converged to unweighted and weighted R factors of 2.4 and 3.0%, respectively. The conductivities of acetonitrile solutions of these complexes suggest 1:1 and 1:2 electrolytes at millimolar concentrations but are highly concentration dependent, indicating that acetonitrile competes effectively with the triflate anions for the free coordination sites on the metal ion. A similar reaction produces in small yield what we believe to be a fully encapsulated ytterbium ion, Yb(L″)(trif)3·CH3CN [L″ = 1,4,6,9,12,14,19,21-octaazabicyclo[7.7.7]tricosane]. In contrast to the di- and monobridged complexes, this new complex does not develop a precipitate in the presence of water, which suggests that the fully encapsulated species is stable toward hydrolysis. The preparation and molecular structure of the first example of a mixed-ligand lanthanide amine complex, Pr(tren)(trien)(trif)3 (trien = triethylenetetramine), is presented in an attempt to characterize the preferred geometry and appropriate bridging units for interconnecting the amine groups. The metal ion is nine-coordinate with tetradentate tren and trien ligands and one coordinated triflate anion. This complex also crystallizes in space group P1 with Z = 2 and a = 9.5259 (12) A?, b = 10.6600 (14) A?, c = 17.0802 (25) A?, α = 74.284 (12)°, β = 76.914 (11)°, and γ = 85.500 (10)°. For 2738 independent data with Fo2 > 3σ(Fo2), a similar refinement converged to unweighted and weighted R factors of 3.9 and 4.6%, respectively.
