Coordination chemistry of phosphonic acids with special relevance to rare earths

The use of phosphonic acids as ligands for metal coordination and design of extended structures is described. The number and type of structures that can be designed is limited only by our ability to synthesize the desired phosphonic acid. The synthesis of metal phosphonates, open framework structures, self-assembled hydrogen bonded structures and rigid highly porous materials will be described. A number of these materials are natural nanoparticles as small as 4 nm with active functionalities. Special attention will be paid to rare earth phosphonates. The great range of coordination compounds that can be designed stems from the tetrahedral nature of the phosphonate group and the large number of protons that can be replaced in polyphosphonic acids. (c) 2005 Elsevier B.V. All rights reserved.