The extraordinary beauty of phosphonates: An overview of their chemistry, technology and applications
Konstantinos D. Demadis
Crystal Engineering Growth and Design Laboratory, Department of Chemistry, University of Crete, Heraklion, Greece
(Poly)phosphonic acids constitute an exciting family of phosphorus compounds. One of the attractive attributes of these molecules is the rich chemistry of the phosphonate moiety, and, in particular, its high affinity for metal ions and mineral surfaces. Whether the phosphonate group belongs to a “small” molecule or to a polymeric matrix, phosphonate-containing compounds have found a phalanx of real-life applications.
Herein, we address all the attractive attributes of molecules that are endowed with phosphonate moieties, and some derivatives with other functional groups (carboxylates, amines, sulfonates, heterocyclics, etc.). Moreover, a mention is made on phosphonate-containing polymers. Last, but not least a general overview is given on the growing field of metal-phosphonate materials, their basic structural architectures and how their structural features can affect their properties.
Phosphonates (as organic molecules) and metal-phosphonates (as solid MOF-type materials) have seen a tremendous growth in the past decades. There are several reasons for that: (a) there have been important advances in the synthesis of several types of phosphonic acids, esters and phosphonate-containing polymers, (b) virtually the metal ions from the entire Periodic Table have been mapped regarding their coordination with phosphonate linkers, (c) The metal-phosphonate compounds that have been synthesized and structurally characterized have been evaluated for their utility in several technological and pharmaceutical applications.
Since the latter have been the principal drivers for the observed growth, we will present the applications that use (or could potentially use) the attributes of phosphonates and metal phosphonates:
- Phosphonic acids as scale inhibitors or scale/deposit dissolvers in water treatment applications
- Phosphonic acids and metal-phosphonates as corrosion inhibitors in water treatment applications
- Phosphonic acids and metal-phosphonates as controlled release and drug delivery systems
- Phosphonic acids and metal-phosphonates as novel consolidants in Archaeology, for the preservation of Cultural Heritage elements
This presentation has the ambition to convince even the most skeptical observer that phosphonate chemistry is not just a curiosity-driven exercise, but a true problem solver.
Keywords: Phosphonate, pharmacology, scale inhibitor, corrosion inhibitor, MOFs, polymers, chemical technology, archaeology