RESUMO
Spontaneous formation of the heteroleptic cadmium(II) bis(terpyridine) complex under ambient conditions can be achieved by a combination of 6,6''-di(2,6-dimethoxylphenyl)-substituted and unsubstituted terpyridine-based ligands. Building on this dynamic heteroleptic complexation, diverse metallo-supramolecular macrocycles and cages were readily assembled in quantitative yields from the predesigned multicomponent systems. The complementary ligation reinforced self-recognition to facilitate the shape-dependent self-sorting of a four-component dynamic library into two well-defined parallelograms. In addition, the subtle lability difference between homoleptic and heteroleptic complexes led to the site-selective CdII -ZnII transmetalation in the Sierpinski triangle. Facile construction of a dodecanuclear tetrahedral metallocage was also realized by using two self-recognizable tritopic building blocks. The photophysical study of the metallo-supramolecules assembled from the d10 metal ions revealed intense ligand-based photoluminescence in solution. The self-assembly strategy described here provides an efficient methodology for building pre-programmable, sophisticated supramolecular architectures furnished with photoactivity.
RESUMO
Predesigned complementary complexation of two 2,2':6',2â³-terpyridine-based ligands was established by installing 2,6-dimethoxyphenyl substituents at the terpyridyl 6,6â³-positions, which provided ancillary ion-dipole interactions in the coordination process and extra π-stacking stabilization in the resultant heteroleptic complex. The high-fidelity self-recognition ligation afforded facile access to the quantitative self-assembly of multicomponent triangle [Cd6L(3)3L(4)3] and ditrigon [Cd15L(3)6L(5)3] (that is, a hexagon with six 120° angles and two alternating edge lengths). It was found that the linear 6,6â³-substituted ditopic motif (L(3)) would be directed by the ligand geometry of L(5) to selectively incorporate into the parallel homoleptic connections in the bilayered framework.
RESUMO
Two hexanuclear metalloprisms possessing three dibenzo[24]crown-8 units were generated in quantitative yields by complexation of the predesigned tetratopic 2,2':6',2''-terpyridine ligand (T) with CdII and ZnII ions, respectively. The prismatic hosts were subsequently self-assembled with the trifunctional guest molecule (TriG) containing dibenzylammonium ions to afford the corresponding metallo-supramolecular pseudo-suit[3]anes. It was serendipitously found that the host-guest inclusion rates could be modulated by the subtle dynamic difference in metal-ligand frameworks, finally leading to a selective encapsulation event in the presence of both metallo-suits.
RESUMO
Three unsymmetrical, 60°-bended bisterpyridine ligands with varying phenylene spacer lengths have been synthesized via the Suzuki-Miyaura coupling reactions. Their self-assembly processes were found to be strongly dependent on the ligand geometry. Upon complexation with Zn(II) ions, only 2,4''-di(4'-terpyridinyl)-1,1':4',1''-terphenyl underwent self-selection to give a trinuclear metallomacrocycle with perfect heteroleptic connectivity and the other two afforded a mixture of constitutional isomers. The metallosupramolecular assemblies were characterized by NMR spectroscopy, electrospray mass spectrometry (ESI MS), and single-crystal X-ray diffraction. In particular, the identification of isomeric architecture was accomplished using tandem mass spectrometry (MS(2)) coupled with traveling wave ion mobility mass spectrometry (TWIM MS).