低价 f 区金属具有通过配体调节的固有发光、电化学和磁性特性,导致这些金属的配位化学对于产生影响现代应用所需的关键见解至关重要。为此,我们合成并表征了一系列 27 种 f 金属离子络合物,包括 Eu II 、 Yb II 、Sm II和 U III以及 La III和 Ce III六核簇,以研究 tris[2] 的影响。 -(2-甲氧基乙氧基)乙基]胺,一种广泛研究的 2.2.2-穴状配体的灵活无环类似物,研究低价 f 嵌段金属的配位化学和光物理性质。我们证明,与溶液中类似的 Eu II穴状化合物相比,配体的灵活性使得发光可调范围更大。此外,该配体还表现出多种与固态 f 区金属的结合模式,这是低价 f 区金属穴状化合物无法达到的。除了充当各种尺寸和氧化态的 f 区金属的配体外,三[2-(2-甲氧基乙氧基)乙基]胺还可使与 f 区金属离子的三价三氟甲磺酸盐配位的水分子去质子化,从而能够分离含有
Process for the preparation of .alpha.-tocopherol derivatives
申请人:Eisai Co., Ltd.
公开号:US05532387A1
公开(公告)日:1996-07-02
A process is provided for the preparation of an .alpha.-tocopherol derivative represented by the following formula (VII): ##STR1## wherein n stands for 0 or an integer of from 1 to 5. According to the process, trimethylhydroquinone and a particular allyl alcohol derivative or a specific alkenyl alcohol are subjected to a condensation reaction in the presence of a fluorosulfonate [M(RSO.sub.3).sub.3 ], a nitrate [M(NO.sub.3).sub.3 ] or a sulfate [M.sub.2 (SO.sub.4).sub.3 ], wherein M represents a scandium, yttrium or lanthanide atom, and R represents a fluorine atom, a fluorinated lower alkyl group, or an aryl group which may be substituted by one or more fluorine atoms. The lanthanide atom means a lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium atom.
Eu<sup>II</sup>-cryptate with optimal water exchange and electronic relaxation: a synthon for potential pO<sub>2</sub>responsive macromolecular MRI contrast agents
作者:László Burai、Rosario Scopelliti、Éva Tóth
DOI:10.1039/b206709a
日期:——
The cryptate [EuII(2.2.2)(H2O)2]2+ displays several interesting features with respect to pO2 responsive MRI contrast agent applications: it is relatively stable against oxidation, it has two inner sphere water molecules, and the water exchange and electron spin relaxation rates are in the optimal range to attain high proton relaxivities, provided the rotation is also optimized.