Trimetallic lanthanide complexes

Application of the model-free methods to axial trimetallic lanthanide complexes with sterically rigid ligands... 

Axial symmetry in trimetallic lanthanide complexes requires the location of the metal ions along the molecular threefold or fourfold axes. Since the terminal coordination sites are different from the central coordination site for symmetry reasons, two different crystal-field parameters 2terminal ancj /)2ccntral must be considered. Equation (61) holds for the general case of three (n = 3) magnetically non-coupled lanthanide metal ions packed along the symmetry axis and eqs. (62)-(64) can be used for homotrimetallic axial complexes. To the best of our knowledge, only one partial study of the NMR data for a >3-symmetrical axial trimetallic complex has been reported (Bocquet et al., 2002 Floquet et al., 2003 see sect. 5.1.2). The Dih-symmetrical complexes [R3(L16-3H)2(OH2)6]3+ do not fit the requirements for axial symmetry since the metal ions are located on mirror planes and not on the threefold axis, but... 

Axial symmetry in trimetallic lanthanide complexes requires the location of the metal ions along the molecular threefold or fourfold axes. Since the terminal coordination sites are different from the central coordination site for symmetry reasons, two different crystal-field parameters 52Q2 entmi considered. Equation (61) holds for the general case... 

Fig. 65. Axial coordinates considered in trimetallic axial lanthanide complexes (adapted from Floquet et al. (2003)).

First, only transition metal complexes are considered, thereby excluding bimetallic and trimetallic compounds with a- or 7r-bonded main group metals, for example, (t7 -C5H4ER3)M(CO) X (M = Fe, Mo E = Ge, Sn, Pb X = Me) (30), as well as lanthanides and actinides (3)). 

The zinc Schiff base complex iV,Ai -bis(3-methoxysalicylidene)ethylene-l,2-diamine, [Zn(97a)] fig. 84), reacts with lanthanide trinitrates giving neutral trimetallic complexes with formula [Zn(N03)(/u-97a)(Ln(N03)2(H20)J (Ln = Nd, Ho, Er, Yb). X-ray crystallography of the Ho° complex reveals that the Zn ion is located in the N2O2 cavity and is 5-coordinate,... 

Both dimetallic and trimetallic chloro-bridged uranium hexamethylbenzene complexes have been reported and the structure of the first lanthanide arene complex (hmb)Sm(AlCl3)3 described. ... 

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