0000000000653906
AUTHOR
Laura Ilander
Recognition of Li+ by a Salophen−UO2 Homodimeric Complex
Self-assembly via mutual U-coordination of the salophen-UO(2) complex 1 creates a dimeric species which is shown to be useful for metal binding. Indeed, the 1 dimer has affinity for alkali metal cations and, interestingly, a marked selectivity for Li(+), determined by electrospray ionization mass spectrometry and (1)H NMR techniques. X-ray diffraction helped in the elucidation of the dimeric complex structure, which presents a crown-ether-type coordination site, in analogy to the more familiar 12-crown-4, responsible for the metal interaction. Comparison with isomer 2, and the salen derivative 3, increases the understanding of the behavior of such systems in solution and in the solid state.
Non-Centrosymmetric Tetrameric Assemblies of Tetramethylammonium Halides with Uranyl Salophen Complexes in the Solid State
Ditopic salophen-UO(2) receptors 1-4 and 7 co-crystallize with tetramethylammonium (TMA) chloride and fluoride salts producing good quality crystals amenable for X-ray diffraction characterization. The arrangement of the receptor and salt units in the crystal lattice is such that tetrameric ball-shaped assemblies are formed, where an inner cluster of four TMA cations are surrounded by an outer shell of four UO(2)-bound anions. These elaborate architectures, which occur in all cases, regardless of a certain degree of structural modification on the receptors, lead to lattices that belong to non-centrosymmetric (NCS) space groups. Interestingly, the tetragonal symmetry of the tetrameric ball-s…