Linkage induced enhancement of fluorescence in metal–carbene bond directed metallacycles and metallacages

Abstract

Four new metal–carbene based metallacycles and metallocages have been obtained using non-AIE active 1,4-dihydropyrrolo[3,2-b]pyrrole based imidazolium ligands. These final assemblies show linkage induced enhanced emission via rigidification.

Silver-Driven Coordination Self-Assembly of Tetraphenylethene Stereoisomer: Construct Charming Topologies and Their Mechanochromic Behaviors

“…This is mainly because coordination of the ligands with Ag­(I) limits the vibration and rotation capabilities of the TPE molecules, triggering the restriction of intramolecular motion (RIM) to enhance the fluorescence emission. Unexpectedly, the maximum emission wavelength of the complexes is almost the same as the ligands, so we speculate that the fluorescence of the complexes mainly comes from the ligands, and the silver ion only plays a role in connecting and rigidding the ligand and trigging the AIE signal, because the fluorescence quantum yield and lifetime of the complexes have significant improvement, which is consistent with the previously reported mechanism . Typically, the fluorescence quantum yield and lifetime of TPE-2by-3- E / Z and Ag-TPE-2by-3- E / Z are nearly identical ((27.40%(3.07 ns) and 33.00%(3.13 ns), 32.13%(3.61 ns) and 31.60%(2.99 ns), respectively), supporting the luminescence of these metal complexes come from the ligands.…”

Self-assembled metallasupramolecular cages towards light harvesting systems for oxidative cyclization

“…Tetraphenylethene (TPE) is weakly emissive in solution but highly emissive in the aggregate state 12 due to the restriction of phenyl ring rotation. 13,14 Recently Stang 15 and other researchers 16 have reported a series of emissive metallacycles and metallacages as AIE active supramolecular complexes by incorporation of TPE functional units within SSCs via coordination driven self-assembly of TPE based donor/(s) and metal-acceptor/(s), which demonstrated their profound use as light emitting and chemical/bio-sensor materials. 17 AIE active supramolecular chromophores possess distinct features including bright emission with significant quantum yield and extraordinary stability in aqueous media, which make them ideal applicants as light emitting donors for energy transfer with water soluble organic dyes.…”

Two Hg(II)-Based Macrocycles Offering Hydrogen Bonding Cavities: Influence of Cavity Structure on Heterogeneous Catalysis

“…Coordination-driven supramolecular self-assemblies are at the pinnacle of supramolecular chemistry. Such a fact is not only related to the presence of well-defined cavities such molecular assemblies offer but also due to the possibility to fine-tune these cavities. − Several such molecular assemblies have been effectively used in host–guest chemistry, − sensing, − drug delivery, − stabilizing reactive intermediates ,− and organic transformations. − Extensive efforts have been made to synthesize assorted molecular assemblies that show remarkable properties. , Efforts vary from the construction of molecular assemblies offering hydrophobic interior space, − and examples include various covalent bonding based assemblies with the objective to tune the cavity structure to suit an application. Efforts have also been made to construct metal–ligand coordination driven molecular assemblies that rely on the geometrical parameters of both metal(s) and ligand(s). − In such molecular assemblies, the interior space has been designed to offer hydrophobic ,− as well as hydrophilic functional groups.…”