Ray and other Techniques for Structural Characterization

This type of dinuclear unit has been reported elsewhere and has been characterized with bis-2-pyridyl-pyrazine or quinoxaline both in Cu [31] and in Ag [32] compounds. However, until now such units have not been used as building blocks (loops) in the construction of coordination polymers, an aspect that is discussed below. Each ligand acts in a bidentate manner with one metal center and as a monodentate system with the other. The two rings that are coordinated to the same metal center are nearly coplanar but the other deviates clearly from this plane. In this way, the structure if this dinuclear unit is very well adapted to the preferred conformation of the free ligand. The relative disposition of the ligands allows the existence of face-to-face n-jt-stacking interactions between the quinoxaline and 

Preparation of Supramolecular Structures with 2,4-Diamino-6-R-l,3 5-triazines and Ag(l) 

These ligands exhibit interesting solid-state structures [34] but discussion of these is beyond the scope of this chapter. This and other similar ligands [35] have been used in the preparation of interesting supramolecular arrays combined with organic substrates that offer complementary donor-acceptor functions and lead to the formation of strong hydrogen bonds. 

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X-Ray and other Techniques for Structural Characterization in the Solid State... 

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