Self-assembly has proven to be a powerful tool for the construction of complex superstructures. The assembly of monomers into supramolecular architectures via non-covalent interactions is chiefly directed by the molecular structures, their functional groups, and environmental conditions. The principal advantage of non-covalent interactions is reversibility, which allows the assembly of monomers into supramolecular structures in situ depending on the local conditions. In addition, the supramolecular approach provides a degree of control over self-assembly at the molecular level, thereby influencing the macroscopic level and facilitating tuning of the bulk material properties. This review discusses the meritorious examples of supramolecular materials constructed through the molecular assembly process, guided by the classical principles of supramolecular chemistry. Furthermore, this year (2017) marks the 50 th anniversary of supramolecular chemistry in honor of the first example of supramolecular structure reported by Charles J. Pedersen and the achievements in the area of supramolecular chemistry ever since.

A Tröger’s base functionalized luminescent nanoscale Zn(II) coordination polymer (TB-Zn-CP) is synthesized and used as selective fluorescence sensor for phenolic nitroaromatics in water.

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Here we discuss the emerging field of luminescent lanthanide-based soft materials with our focus on the different approaches used for their design and synthesis as well as manipulations of their functional properties.

Herein we present the synthesis and the photophysical evaluation of water-soluble chiral ligands (2·(R,R) and 2·(S,S)) and their application in the formation of lanthanide directed self-assembled structures. These pyridine-2,6-dicarboxylic amide based ligands, possessing two naphthalene moieties as sensitising antennae, that can be used to populate the excited state of lanthanide ions, were structurally modified using 3-propanesultone and caesium carbonate, allowing for the incorporation of a water-solubilising sulfonate motif. We show, using microwave synthesis, that Eu(III) forms chiral complexes in 1 : 3 (M : L) stoichiometries (Eu·[2·(R,R)]3 and Eu·[2·(S,S)]3) with these ligands, and that the red Eu(III)-centred emission arising from these complexes has quantum yields (Φtot) of 12% in water. Both circular dichroism (CD) and circular polarised luminescence (CPL) analysis show that the complexes are chiral; giving rise to characteristic CD and CPL signatures for both the Λ and the Δ complexes, which both possess characteristic luminescence dissymmetry factors (g(lum)), describing the structure in solution. The self-assembly process was also monitored in situ by observing the changes in the ligand absorption and fluorescence emission, as well as in the Eu(III) luminescence. The change, fitted using non-linear regression analysis, demonstrated high binding affinity for Eu(III) which in part can be assigned to being driven by additional hydrophobic effects. Moreover, using CD spectroscopy, the changes in the chiroptical properties of both (2·(R,R) and 2·(S,S)) were monitored in real time. Fitting the changes in the CD spectra allowed for the step-wise binding constants to be determined for these assemblies; these matched well with those determined from both the ground and the excited state changes. Both the ligands and the Eu(III) complexes were then used in the formation of hydrogels; the Eu(III)-metallogels were luminescent to the naked-eye.

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The synthesis, photophysics and biological investigation of fluorescent 4-amino-1,8-naphthalimide Tröger's bases (TB-1-TB-3) and a new Tröger's base p-cymene-Ru(ii)-curcumin organometallic conjugate (TB-Ru-Cur) are described; these compounds showed fast cellular uptake and displayed good luminescence and cytotoxicity against cervical cancer cells.