Functionalisation of gold nanoparticles with ruthenium(II) polypyridyl complexes for their application in cellular imaging.

Two new dinuclear Ru(ii) polypyridyl complexes containing an alkyl disulphide functionalised bipyridine-based ligand and either 1,10-phenanthroline (phen) or 1,4,5,8-tetraazaphenanthrene (TAP) as ancillary ligands have been synthesised and characterised. Their attachment onto the surface of gold nanoparticles (AuNPs, average diameter of ca. 2.5 nm) resulted in the formation of two new water-soluble Ru(ii)-AuNP conjugates that combine the advantageous properties of both moieties. Both free complexes show the attractive photophysical properties of Ru(ii) polypyridyl complexes and a rapid cellular uptake in HeLa cervical cancer cells. However, their corresponding gold conjugates displayed lower quantum yields than those determined for the free complexes presumed to be due to an energy transfer quenching of the Ru(ii) luminescence by interaction with the gold surface. Despite their diminished luminescence, confocal fluorescence microscopy studies revealed that the Ru(ii)-AuNP conjugates are successfully internalised into HeLa cells and better tolerated than their free complex counterparts after 24 h incubation, which makes them potential luminescent nanomaterials for bioimaging applications.

Recent advances in the development of luminescent lanthanide-based supramolecular polymers and soft materials.

Combination of different properties has always proven effective in the generation of hybrid materials with novel interesting properties. Ln(iii) containing materials possessing multiple properties are useful in a wide range of applications. In this article, key and recent examples of metallo-supramolecular polymers in the formation of gels, soft polymeric materials and films are discussed. There is a focus on the use of trivalent lanthanide, Ln(iii), ions to provide soft materials with advanced mechanical and luminescence properties for applications in developing electronic- and bio-technologies. This frontier article has been written with the intention of reaching a broad range of readers from various backgrounds such as chemistry, materials chemistry, spectroscopy and biochemistry. Additionally, we evaluate how the unique and versatile properties of such hybrid materials can be tuned and explored to enhance the efficiency, as well as research, for new ones. Finally, an assessment of the current state-of-the-art and our outlook for the future of this field is made.

Synthesis, structural characterisation and antiproliferative activity of a new fluorescent 4-amino-1,8-naphthalimide Tröger's base-Ru(ii)-curcumin organometallic conjugate.

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.

Norbornene chaotropic salts as low molecular mass ionic organogelators (LMIOGs).

Phenylalanine functionalised norbornene (9:Na) functions as a potent, low molecular-mass (MW = 333 Da) ionic organogelator with a minimum gelating concentration of 0.5 wt% in THF, i-PrOH, 1,4-dioxane and n-BuOH. Fibrous crystals form in the gel and X-ray crystallography identified a cation mediated helical assembly process controlled by the chirality of the phenylalanine. In addition to excellent gelating properties 9:Na readily forms aqueous biphasic and triphasic systems.

A supramolecular Tröger's base derived coordination zinc polymer for fluorescent sensing of phenolic-nitroaromatic explosives in water.

A V-Shaped 4-amino-1,8-napthalimide derived tetracarboxylic acid linker (L; bis-[N-(1,3-benzenedicarboxylic acid)]-9,18-methano-1,8-naphthalimide-[b,f][1,5]diazocine) comprising the Tröger's base (TB) structural motif was rationally designed and synthesised to access a nitrogen-rich fluorescent supramolecular coordination polymer. By adopting the straight forward precipitation method, a new luminescent nanoscale Zn(ii) coordination polymer (TB-Zn-CP) was synthesized in quantitative yield using Zn(OAc)2·2H2O and tetraacid linker L (1 : 0.5) in DMF at room temperature. The phase-purity of as-synthesised TB-Zn-CP was confirmed by X-ray powder diffraction analysis, infra-red spectroscopy, and elemental analysis. Thermogravimetric analysis suggests that TB-Zn-CP is thermally stable up to 330 °C and the morphological features of TB-Zn-CP was analysed by SEM and AFM techniques. The N2 adsorption isotherm of thermally activated TB-Zn-CP at 77 K revealed a type-II reversible adsorption isotherm and the calculated Brunauer-Emmett-Teller (BET) surface area was found to be 72 m2 g-1. Furthermore, TB-Zn-CP displayed an excellent CO2 uptake capacity of 76 mg g-1 at 273 K and good adsorption selectivity for CO2 over N2 and H2. The aqueous suspension of as-synthesized TB-Zn-CP showed strong green fluorescence (λmax = 520 nm) characteristics due to the internal-charge transfer (ICT) transition and was used as a fluorescent sensor for the discriminative sensing of nitroaromatic explosives. The aqueous suspension of TB-Zn-CP showed the largest quenching responses with high selectivity for phenolic-nitroaromatics (4-NP, 2,4-DNP and PA) even in the concurrent presence of other potentially competing nitroaromatic analytes. The fluorescence titration studies also provide evidence that TB-Zn-CP detects picric acid as low as the parts per billion (26.3 ppb) range. Furthermore, the observed fluorescence quenching responses of TB-Zn-CP towards picric acid were highly reversible. The highly selective fluorescence quenching responses including the reversible detection efficiency make the nanoscale coordination polymer TB-Zn-CP a potential material for the discriminative fluorescent sensing of nitroaromatic explosives.

Supramolecular coordination polymers using a close to 'V-shaped' fluorescent 4-amino-1,8-naphthalimide Tröger's base scaffold.

A V-shaped 4-amino-1,8-naphthalimide derived dipyridyl ligand comprising the Tröger's base structural motif has been synthesised and subsequently used in the formation of two new supramolecular coordination polymers.