Coordination complexes incorporating pyrophosphate: structural analysis and magnetic properties

Inorganic pyrophosphate (PPi) is a diphosphate tetra-anion P2O7 4− that is ubiquitous in nature. PPi plays a central role in a variety of bioenergetic processes, the –P–O–P– moiety acting, for instance, as the main chemical form in which energy is circulated in living cells. Pyrophosphate has also been shown to be pivotal in certain catalytic processes such as the conversion of butane to maleic anhydride. More recently, significant efforts have been devoted to check its ability in mediating magnetic interactions between paramagnetic transition metal ions and to investigate its potentiality and effectiveness as a component of drugs/prodrugs. Considering its biological relevance and the multidentate nature that makes it an ideal ligand in the field of the coordination chemistry, there is a growing interest in the use of this anion in building new class of molecules/compounds for different purposes. Here we focus on the coordination chemistry of pyrophosphate and the magnetic properties of the compounds that incorporate the anion as a ligand. Our recent results in the field are presented, ranging from zeroto multi-dimensional structures and from classical antiferromagnetic coupling to spin canting phenomena.