Synthesis, solid-state characterization and solution studies of new phytate compounds with Cu(II) and 1,10-phenanthroline: Progress in the structural elucidation of phytate coordinating ability

Within all the eukaryotic cells there is an important group of biomolecules that has been potentially related to signalling functions: myo-inositol phosphates (InsPs). In nature, the most abundant member of this family is the so called phytate (InsP6, L12-). The importance of the interaction of InsP6 with cations has been recognized during the last few years, and any attempt to know the function of this molecule in eukaryotic cells must include the fact that InsP6 will be strongly associated with simple inorganic or organic ammonium cations. In this work we expand on our earlier findings by studying the systems phen-phytate (phen = 1,10-phenanthroline) and Cu(ii)-phen-phytate. The structures of (Hphen)4(H8L)·7.5H2O and [Cu5(H7L)2(H2O)2(phen)5]·23H2O are presented. Solution studies of the binary and ternary systems were also performed by means of potentiometric titrations at 37.0 °C and 0.15 M ionic strength. The work was completed with a molecular modelling study. All this information is essential in the process of gaining reliable structural knowledge about the most important InsP6 species in the in vitro and in vivo experiments, and how these features modulate their probable biological functions.