Matere Bonds in Technetium Compounds: CSD Survey and Theoretical Considerations

Abstract

Noncovalent interactions involving metals as electron acceptors are continuously under investigation. The term “matere bond” has been proposed to identify noncovalent donor–acceptor interactions where elements of group 7 of the periodic table play the role of the electrophilic site. Most of the works on matere bonds involve rhenium atoms usually in +7 oxidation state. This work emphasizes for the first time their importance in technetium derivatives in several oxidation states (+7, +6, +5, and +3). The Cambridge Structural Database (CSD) in combination with density functional theory (DFT) calculations are used to demonstrate the structure directing role of matere bonds in X-ray structures, even involving anion⋯anion interactions. Further characterization of the matere bonds is provided using Molecular Electrostatic Potential (MEP) surface calculations, the “Quantum Theory of Atoms in Molecules” (QTAIM), and Natural Bond Orbital (NBO) analyses. It should be emphasized that some types of matere bonds reported herein have not been previously described in literature.