Lanthanide Assemblies in the Solid State

The solid phase lends itself to the preparation of lanthanide containing heterometallic materials. In this case the choice of lanthanide complexes is ample since it is not only limited to kinetically inert complexes. The solid state acts as kinetic trap so that building blocks formed by p-diketonates are widely applied for designing multimetallic architectures such as the one represented in Fig. 9.3 [17—19]. 

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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