Lanthanide complexes with bipy, phen

Complexes Ln(bipy)2(N03)3 have been studied in more detail than the other bipy complexes all appear to have 10-coordinate structures with all nitrates present as bidentate ligands. The coordination geometry has been variously described as a bicapped dodecahedron and as a sphenocorona. Unlike the La complex, the Lu complex does not possess disorder about the twofold axis. Li N distances are 2.46-2.67(1) A and Lu—O distances in the range 2.426(9)-2.556(9) A. [Y(bipy)2(N03)3] is, like [Y(phen)2(N03)3], isostructural with its lanthanide analogues. Similarly, the structure of [Nd(bipy)2(N03)3] has been shown to be isostructural with [Ln(bipy)2(N03)3] (Ln = Y, La, Lu). A number of compounds Ln(bipy)3(N03)3 (Ln = Ce, Pr, Nd, Yb) have been reported the neodymium complex was shown to be [Nd(bipy)2(N03)3]. bipy, with the third bipy molecule not associating with the neodymium-containing complex. ... 

These ligands are now well represented in complexes with the lanthanides, but were not investigated until 1962, when a study in aqueous solution using a Job s plot method, e.g. at 451 nm for Ho ", showed that a complex Ho(phen)2" was formed. Pr, Nd and Er tripositive ions were also studied, but no solid products were characterized. Indeed, stability constants in water are possibly too low for a solid complex to be isolated. A little later, there were several reports of the isolation of bipyridyl and 1,10-phenanthroline complexes from ethanolic solution. It is perhaps of interest that at this time, the lanthanides were believed not to form stable amine complexes and the role of higher coordination numbers in lanthanide complexes was not fully appreciated. Complexes isolated included the stoichiometries M(N03)s(bipy)2, where M = M(NCS)3(bipy)3, where M = La, Ce, Dy M(MeC02)3(bipy),... 

All the examples reported so far appear to contain N-bonded thiocyanate groups and to dissociate readily in solution. Thus, [ScL3](NCS)3 (L = bipy or phen) has been prepared and characterized 223). Treatment with warm EtOH gives [ScL2(NCS)2](NCS) where the formulation is supported by conductivity measurements (in CHgCN or CH3NO2) and infrared mull spectra in aqueous solutions the coordinated NCS is displaced 223, 225, 464). Other mixed liquid complexes of these metals with NCS are listed in Table XX. A 1 1 adduct is formed between 1,3,5-trinitrobenzene and several lanthanide thiocyanates. No... 

A simpler but equally effective approach has been employed by Ward and coworkers [25] in the preparation of coordination polymers using luminescent anionic complexes. Here transition metals with emissive MLCT states act as effective sensMsers for lanthanide emission in the NIR [25]. In this case cyanide groups were used as bridging units starting from stable Ru " complexes and simple Ln salts. Examples include [Ru(Bipy)(CN)4] [26,27], [Ru(Phen) (CN)4] - [28], [Ru(Bpym)(CN)4] -, [Ru(CN)4]2([i-Bpym) 4- [29], [Ru(Hat)(CN)4] - [25], [Ru(CN)4]3(p"-Hat) -, [ Ru(CN)4 2([i -Hat)]4-, [Cr(CN)6]"-, and [Co(CN)6] - [30]. The advantage of this method is that the building blocks are already kinetically stable in solution and the solid structure is dictated by the coordination number adopted by the lanthanide ion (Fig. 9.5). 

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