HHBEDpa: Octadentate Chelate after A. E. Martell.

HHBEDpa, a new octadentate chelator inspired by the 1960s ligand HBED of Arthur E. Martell, has been investigated for a selection of trivalent metal ions useful in diagnostic and therapeutic applications (Sc, Fe, Ga, In, and Lu). Complex formation equilibria were thoroughly investigated using combined potentiometric and UV-vis spectrophotometric titrations which revealed effective chelation and high metal-sequestering capacity, in particular for Fe, log = 36.

Phosphonate Chelators for Medicinal Metal Ions.

A family of phosphonate-bearing chelators was synthesized to study their potential in metal-based (radio)pharmaceuticals. Three ligands (Hphospa, Hdipedpa, Heppy; structures illustrated in manuscript) were fully characterized, including X-ray crystallographic structures of Hphospa and Hdipedpa. NMR spectroscopy techniques were used to confirm the complexation of each ligand with selected trivalent metal ions.

Contribution of the Covalent Component of the Hydrogen-Bond Network to the Properties of Liquid Water.

Many remarkable properties of liquid water originate from the ability of its molecules to form hydrogen bonds, each of which emerges as a combination of electrostatic, polarization, dispersion, and donor-acceptor or covalent interactions. In this work, ab initio molecular dynamics was tailored to isolate and switch off the covalent component of interactions between water molecules in simulations. Comparison of simulations with and without covalency shows that a small amount of intermolecular electron density transfer has a profound effect on the structure and dynamics of the hydrogen-bond network and thus on observable properties of room-temperature liquid water.

Communication: Compact orbitals enable low-cost linear-scaling ab initio molecular dynamics for weakly-interacting systems.

Today, ab initio molecular dynamics (AIMD) relies on the locality of one-electron density matrices to achieve linear growth of computation time with the system size, crucial in large-scale simulations. While Kohn-Sham orbitals strictly localized within predefined radii can offer substantial computational advantages over density matrices, such compact orbitals are not used in AIMD because a compact representation of the electronic ground state is difficult to find. Here, a robust method for maintaining compact orbitals close to the ground state is coupled with a modified Langevin integrator to produce stable nuclear dynamics for molecular and ionic systems.