Hybrid Multifunctional Materials Based on Phosphonates, Phosphinates and Auxiliary Ligands

Hybrid inorganic-organic materials are a vast class of functional solids in which the inorganic and the organic parts intimately contribute to the overall chemical reactivity. This chapter surveys the coordination polymers (CPs) based on transition metal phosphonates and phosphinates where an auxiliary ligand is also present. These auxiliary ligands are divided into two classes: the N- and O-donors. Among the N-donors, the chapter focuses on the ligands that normally do not contribute to extend the dimensionality, like the chelating ones (2,2'-bipyridine, 1,10-phenantroline, terpyridine and related molecules) and those that are able to connect different metals, thus influencing the overall connectivity (4,4'-bipyridine, imidazole and related molecules). Among the O-donors, it also focuses on carboxylic ligands that are able to connect the metal ions in different manners, thus strongly contributing to determine the structure and the reactivity. The chapter focuses on gas absorption, optical and magnetic properties primarily on the open-framework materials.