Beyond AIE (aggregation-induced emission) phenomena in small molecules, supramolecules with AIE properties have evolved in the AIE family and accelerated the growth of supramolecular application diversity. Inspired by its mechanism,...
Tunable fluorescence emission materials play a critical role in many fields such as biology and chemistry. With respect to metallo‐supramolecular assemblies, the construction of 3D tunable‐fluorescent supramolecular assemblies with 2,2′:6′,2″‐terpyridine (tpy) is still in its infancy. In this study, two luminous 3D supramolecular prisms self‐assembled with two terpyridine‐based tetraphenylethylene (TPE) ligands and metal Zn(II) are prepared, and the influence of hydrophobic alkyl chains on tunable fluorescence is further explored. By exploiting hydrophobic properties, the prism SA exhibits tunable visible‐light emission in the molecular‐aggregated state. Moreover, SA forms left‐hand and right‐hand helical nanofibers by hierarchical self‐assembly. However, the prism SB without hydrophobic chains does not exhibit tunable fluorescence emission, and only random spherical aggregates after hierarchical self‐assembly are formed. This study can aid to further strengthen the understanding about the effect of hydrophobic segments on photophysical properties and hierarchical self‐assembly of discrete supramolecular architectures.
Inspired by the architecture of single-atom
catalysts,
where the
monodispersed metal atoms are widely distributed but stabilized by
various coordination circumstances, the biomimetic design and synthesis
of metalloporphyrin-containing nanocages have been demonstrated in
this study. The nanocages were fabricated through a coordination-driven
self-assembly process, and the Mn(III) porphyrin-based one was found
to have exclusively peroxidase-like activity at pH 6.0 with neither
oxidase nor catalase-like activity under the routine conditions. Benefiting
from this, we demonstrated the wide applicability and convenient usage
of an Mn(III)-containing supramolecular nanocage (Mn-PC) in the one-step
detection of H2O2, sarcosine, and glucose through
various oxidase-involved reactions, with a satisfactory detection
limit and eligible specificity. Real samples including H2O2 in lens care solution, sarcosine in human urine, and
glucose in human serum were also assayed, showing an adequate recovery
rate. Such a specific activity originates from the super-consistent
microstructure of each catalytic unit, which means that the active
site of manganese porphyrin was “protected” by the confinement
of the nanocage. This also helps to sustain the super long-term activity
even after 545 days of storage. Furthermore, the intrinsic electronic
structure of the Mn(III)-containing supramolecular nanocage endows
the ability in electrochemical detection of H2O2 and glucose. Our smart design toward the supramolecular nanocages
with a defined structure and quantity contributes to the construction
of the ingenious sensing platform and has guiding significance for
architectural design of nanozymes.
In
this study, two trigonal prisms based on the 1,3,5-triazine
motif (SA and SB), distinguished by hydrophobic
groups, were prepared by the self-assembly of tritopic terpyridine
ligands and Zn(II) ions. SA and SB exhibited
high luminescence efficiencies in the solid state, overcoming the
fluorescence quenching of the 1,3,5-triazine group caused by π–π
interactions. Notably, SA and SB exhibited
different luminescence behaviors in the solution state and aggregation
state. SB with 12 alkyl chains exhibited extremely weak
fluorescence in a dilute solution, but its fluorescence intensity
and photoluminescence quantum yield (PLQY) were significantly enhanced
in the aggregated state (with the increase in the water fraction),
especially in the solid state. Different from the gradually enhanced
efficiency of SB, the PLQY of SA gradually
decreased with the increase in aggregation but still maintained a
high luminescence efficiency. These two complexes exhibited different
modes to solve the fluorescence quenching of 1,3,5-triazine in the
solid state. The hierarchical self-assembly of SB exhibited
nanorods owing to the hydrophobic interactions of alky chains, while SA aggregated into spheres under the influence of π–π
interactions.
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