Zirconium and hafnium cations rapidly cleave model phosphodiesters in acidic aqueous solutions

Hydrolysis of phosphatidylcholine by cerium(IV) releases significant amounts of choline and inorganic phosphate at lysosomal pH

“…In this paper, we have tested unactivated phosphatidylcholine (1) against Ce(IV), Zr(IV), Hf(IV), Co(II), Cu(II), Eu(III), La(III), Ni(II), Pd (II), Y(III), Yb(III), and Zn(II), metal ions which have been used to hydrolyze activated and unactivated amide and/or phosphate ester bonds in peptides, nucleic acids, and other in compounds [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. To the best of our knowledge, the present work represents the first example of a research study that has focused on metal-assisted cleavage of unactivated phospholipids at lysosomal pH (~4.8).…”

Tetravalent Metal Catalyzed Hydrolysis of Cyanofenphos: A Delayed Neurotoxic Organophosphorus Compound

“…The literature reports indicated that at around pH 2.0, Zr(IV) exists as coordination complex of water {e.g. Zr8 (OH)20(H2O)24Cl12}, whose geometry has been determined to be octameric [20], and under similar conditions Hf(IV) has been reported to exhibit a similar chemistry [19]. These octameric species may be formed by bridging of two tetramers via four single OH -bridges and each metal cations of the octamer would bind to three H2O molecules.…”

“…It has been reported that, because of increasing Lewis acid strength and deprotonation ability of metal bound water molecule, due to increasing positive charge on metal cation, the tetravalent metal cations like Zr 4+ , Ce 4+ , Hf 4+ and Th 4+ are found to be highly reactive towards activated phosphodiesters like bis(p-nitrophenyl phosphate) [11,19], dimethyl phosphate [14], hydroxyethyl p-nitrophenyl phosphate [19] etc. and neutral triesters like methyl parathion [22].…”

Rapid hydrolysis of phosphate monoesters by zirconium(IV) complexes in neutral solution

“…60 years later two detailed kinetic studies on the reaction of ZrCl4 with the phosphate diester bis(p-nitrophenyl) phosphate and with a DNA dinucleotide have been published [6,7]. Due to its high positive charge, small ionic radius, hard…”

“…orders of magnitude rate accelerations have been reported for ZrCl4-mediated phosphate diester hydrolysis [6,7]. However, the solution chemistry of ZrCl4 is governed by the formation of ill-defined polynuclear hydroxo-bridged species.…”