Coordination chemistry solid-state materials

Iron(IV), (V), and (VI) centers are also found in solid-state materials, the coordination chemistry of which is of considerable interest because unusual structures and remarkable electronic and catalytic properties are encountered [184]. Reviews of the corresponding Mossbauer properties are found in [185-187]. 

The structural chemistry associated with polysulfide molecules and materials reflects the stereochemical freedom of the sulfur atom as mentioned above, disulfide ligands can coordinate in a number of ways. Similarly, larger rings may adopt a variety of geometries (from X-ray studies) and the evidence that is available suggests that many of the rings are fluxional in solution. Muller has classified and discussed some aspects of this problem for molecular species, but the rationalization of the structures adopted in solid-state materials is not yet complete. ... 

There has been tremendous growth in the chemistry of zirconium and hafnium since the 1960s. Many of the developments have been the result of efforts to uncover new applications. One of the major driving forces has been the rising importance of single-site alkene polymerization catalysis and catalysis in general. Other motivations have included a variety of strategies to develop molecular compounds as precursors to specific solid-state materials. In all cases, the fundamental chemical issues often are reduced to the development of new coordination chemistry. 

Ultimately, the chemistry of lanthanide-containing MOFs and CPs can be regarded as a blend between the coordination chemistry of molecular and solid-state materials. The structural themes present in solid-state materials (e.g., edge sharing of polyhedra) and the coordination preferences seen in molecular compounds (e.g., N-, O- donors) are essentially what form the structural basis for extended topologies. 

We are ourselves engaged in such a synthetic endeavour and we report here on some typical structural problems encountered in coordination and solid state chemistry of these low-dimensional materials. Indeed, the properties of these compounds are very sensitive to order and disorder, purity and defects and chemical modifications such as doping, insertion or intercalation their understanding needs careful structural characterization. Extended X-Ray Absorption Fine Structures (EXAFS) spectroscopy possesses some unique features which can contribute to the solution of well-defined cases to set up correlations between structural and physical properties. 

The use of coordination compounds in SCFs is rather larger than one might initially expect [1]. The major applications can be divided into two broad categories (1) the transport of metals, which includes selective extraction, deposition of metal and oxide films and impregnation of metals as a route to composite materials and (2) synthesis and reactions, which covers a wide range of topics from the synthesis of oxides and other solid state materials to the reactions of organometallic compounds. This chapter focuses on the synthesis of organometallic compounds because this is the area where the majority of the new experimental techniques have been developed. The chapter complements chapter 3.1 and 3.2 which cover, respectively, vibrational and NMR spectroscopy, because IR spectroscopy, and to a lesser extent NMR, have been key tools in the exploration of this chemistry. 

---