ABSTRACT
The application of chalcogen bonding (ChB) to anion recognition is an underdeveloped area of host-guest supramolecular chemistry. The chemical instability of heavier chalcogen derivatives may in part be responsible for the lack of progress. Herein, the synthesis of a new structurally simple, tellurium-based ChB binding motif is reported, the robust stability of which has enabled the thermodynamic properties for ChB halide anion binding in polar aprotic and wet protic organic solvent media to be elucidated. The thermodynamic data reveals how the subtle interplay between ChB host, anion guest and solvent dictates halide binding selectivity and affinity trends. These findings help to provide a deeper insight into the nature of the ChB-anion interaction.
Subject(s)
Macrocyclic Compounds/chemistry , Organometallic Compounds/chemistry , Selenium/chemistry , Tellurium/chemistry , Anions/chemistry , Models, Molecular , Solvents , Temperature , ThermodynamicsABSTRACT
A series of enantiopure ruthenium(II) polypyridyl complexes are reported that feature pendant pyridyl groups suitable for building larger self-assembled structures. The complexes are characterized in detail in solution using NMR spectroscopy, cyclic voltammetry, and photophysical methods and in the solid state using single-crystal X-ray crystallography. The complexes are luminescent, displaying long excited-state lifetimes that are quenched when the pendant pyridyl groups are protonated. Reaction with cadmium(II) ions results in the formation of a mixed-metal one-dimensional coordination polymer, which was characterized by single-crystal X-ray crystallography.
ABSTRACT
An asymmetric 'Pacman' metalloligand, [Zn(PXT)], which features a cofacial ZnII -porphyrin unit (P) covalently attached to a terpyridine (T) chelating group via a rigid xanthene (X) moiety has been prepared, and its interactions with several different trivalent LnIII cations (NdIII , GdIII , YbIII and LuIII ) have been examined. The formation of 1:1 metal-ligand complexes was monitored by 1 Hâ NMR spectroscopy and corroborated by HRMS data. Solution-stability constants were determined by UV/Vis titration, and the resulting complexes with NdIII or YbIII demonstrated sensitised emission in the NIR region due to energy transfer from the ZnII -porphyrin donor to LnIII acceptor. The energy transfer was investigated by transient absorption techniques, which provided insight into the kinetics and efficiency of the antenna effect.
