Monodispersed hollow layered double oxide spheres were constructed, providing sufficient microchannels and active sites for the efficient adsorption of anionic dyes.
The living supramolecular polymerization technique provides an exciting research avenue. However, in comparison with the thermodynamic spontaneous nucleation, using simple monomers to realize living supramolecular polymerization is hardly possible from an energy principle. This is because the activation barrier of kinetically trapped simple monomer (nucleation step) is insufficiently high to control the kinetics of subsequent elongation. Here, with the benefit of the confinement from the layered double hydroxide (LDH) nanomaterial, various simple monomers, (such as benzene, naphthalene and pyrene derivatives) successfully form living supramolecular polymer (LSP) with length control and narrow dispersity. The degree of polymerization can reach ~6000. Kinetics studies reveal LDH overcomes a huge energy barrier to inhibit undesired spontaneous nucleation of monomers and disassembly of metastable states. The universality of this strategy will usher exploration into other multifunctional molecules and promote the development of functional LSP.
Chiral supramolecular assembly (CSA) based on achiral molecules has provided important clues to understand the origin of biological chirality. However, a simple achiral monomer faces the challenge of chiral stacking with the absence of a chiral resource. The difficulty is that simple achiral monomer lacks steric repulsion to provide asymmetry during hierarchical assembly, which is a prerequisite for chiral stacking with an angle. Moreover, during chiral stacking of achiral molecules or units, the righthanded and left-handed chiral supramolecular isomers (CSIs) are equally formed due to the mirror-imaged conformation, which leads to chirality silence. Here, with the benefit of two-dimensional confinement space of layered double hydroxide (LDH), simple achiral molecules can be arranged to staggered bilayer arrays by imprinting the topological structure of LDH. Once LDH is removed, these staggered arrays can form asymmetric living seeds, which can further elongate to living units with the advantage of living supramolecular polymerization (LSP) by following off-pathway. Due to the asymmetry of living units, the possible chiral stacking outcomes, CSIs, are not mirrorimaged. With the increase of the molecular number in living units, the energy difference between CSIs can be amplified by selfreplication of LSP, leading to handedness preference. Thus, the detectable CSA is mainly derived from the CSI with energetically favored hierarchical structure. Thus, our strategy breaks the stereotype that the complex molecular structure and symmetry breaking mechanism are necessary for the formation of detectable CSA by achiral molecules.
The successful preparation of supramolecular block copolymers
(SBCPs)
by living supramolecular assembly technology requires two kinetic
systems in which both the seed (nucleus) and heterogenous monomer
providers are in non-equilibrium. However, employing simple monomers
to construct the SBCPs via this technology is almost impossible because
the low spontaneous nucleation barrier of simple molecules prevents
the formation of kinetic states. Here, with the help of confinement
from layered double hydroxide (LDH), various simple monomers successfully
form living supramolecular co-assemblies (LSCA). LDH overcomes a considerable
energy barrier to obtain living seeds to support the growth of the
inactivated second monomer. The ordered LDH topology is sequentially
mapped to the seed, second monomer, and binding sites. Thus, the multidirectional
binding sites are endowed with the ability to branch, making the branch
length of dendritic LSCA reach its maximum value of 3.5 cm so far.
The strategy of universality will guide exploration into the development
of multi-function and multi-topology advanced supramolecular co-assemblies.
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