Aquation

About: Aquation is a research topic. Over the lifetime, 1443 publications have been published within this topic receiving 17507 citations.

Aquation of the ruthenium-based anticancer drug NAMI-A: a density functional study.

Abstract: We carried out density functional theory (DFT) calculations to investigate the thermodynamics and the kinetics of the double aquation reaction of the anticancer drug NAMI-A. Three explicit water molecules were included in the calculations to improve the PB solvation energies. Our calculations show that the chloride substitution reactions on the considered Ru(III) octahedral complex follow a dissociative interchange mechanism, Id, passing through a loose heptacoordinate transition state. We calculated an activation enthalpy and free energy for the first aquation step of 101.5 and 103.7 kJ mol-1, respectively, values that are in good agreement with the available experimental results. The activation enthalpy and free energy for the second aquation step were found significantly higher, 118.7 and 125.0 kJ mol-1, again in agreement with the experimental evidence indicating a slower rate for the second aquation.

Synthesis, X-ray crystallographic, and NMR characterizations of platinum(II) and platinum(IV) pyrophosphato complexes.

Abstract: A series of mononuclear cis-diamineplatinum(II) pyrophosphato complexes containing ammine (am), trans-1,2-cyclohexanediamine (dach), and 1,2-ethanediamine (en) as the amine ligands were synthesized and characterized by 31P and 195Pt NMR spectroscopy. Chemical shifts of 31P NMR resonances of these completely deprotonated complexes appear at 2.12, 1.78, and 1.93 ppm, indicating a coordination chemical shift of at least 8 ppm. The 195Pt NMR chemical shifts for the am and dach complexes were observed at −1503 and −1729 ppm. The complexes are highly stable at neutral pH; no aquation due to the release of either phosphate or amine ligands was observed within 48 h. Furthermore, no partial deligation of the pyrophosphate ligand was detected within several days at neutral pH. At lower pH, however, release of a pyrophosphate ion was observed with concomitant formation of a bridged pyrophosphatoplatinum(II) dinuclear complex. The extended crystal structure containing the dach ligand revealed a zigzag chain stacked i...