摘要:
The reaction of Nd(OTf)(3) (OTf = O3SCF3) with two molar equivalents of LiCp '' [Cp '' = C5H3(SiMe3)(2)-1,3] in thf solution generated the blue, tetrametallic dimer [{Nd(eta(5)-Cp '')(2)(mu(2)-k(2)-O3SCF3)(mu(3)-k(3)-O3SCF3)Li(thf)}(2)] (1a), which has been shown by X-ray crystallography to contain a tricyclic, ladder-like scaffold with Nd and Li cations and OTf anions at its core. Compound la was relatively labile, being readily cleaved by a variety of donor molecules. 18-Crown-6 efficiently encapsulated the lithium cation to yield the salt [Li(18-crown-6)][Nd( eta(5)-Cp '')(2)(k(1)-O3SCF3)(k(2)-O3SCF3)] (2). Addition of N,N,N',N'-tetramethylethylenediamine (tmeda) afforded the monomeric bimetallic [Nd(eta(5)-Cp '')(2)(mu(2)-k(2)-O3SCF3)(2)Li(tmeda)] (3), while the more rigid donor 2,2'-bipyridine (bipy) produced the neutral, Li-free complex [Nd(eta(5)-Cp '')(2)(K-1-O3SCF3)(bipy)] (4). The molecular and crystal structures of 2-4, as well as that of 1b, the unstable La analogue of la, have been determined by X-ray methods. (c) 2006 Elsevier B.V. All rights reserved.