Triple Emission from Organic/Inorganic Hybrid Nanovesicles in a Single Excitation

Abstract

Dedicated to Professor Klaus MüllenThe fabrication of shape-defined luminescent nano/microscale objects from small molecules has attracted increasing attention among scientist owing to their unique optical and electronic properties. [1,2] Particularly, the generation of multicolor emissions from single organic and organic/inorganic hybrid nano-objects in a singlewavelength excitation is of great interest due to their potential use in solid-state lighting and color barcode applications. Until now, no reports are available on a molecularly engineered single organic or organic/inorganic nano/micro structure displaying blue-, greenand red-color triple emissions. Recently, we reported [2] the preparation of nanostructure templates self-assembled from ligand molecules and subsequently demonstrated their use by performing "coordination chemistry on the surface of the organic ligand super-structures " to generate dual-emitting (blue and red) organic/inorganic hybrid nanotubes. In our bottom-up self-assembly technique, in addition to supramolecular interactions, [3] the growth, final-shape and dimension of the nano-objects are all dependent on parameters such as: 1) molecular design, 2) solvent polarity, and 3) molecular concentration.Adopting our method, [2] we have envisioned to fabricate tricolor (blue, green and red) emitting organic/inorganic nanoobjects by single-wavelength excitation in a single pot. This goal indeed required a step-by-step approach (Scheme 1): i) careful design and synthesis of a novel dual (blue and green) emitting amphiphilic-type ligand molecule (1), ii) selection of appropriate solvent(s) for the growth of self-assembled nanostructure templates, and iii) subsequent sub-stochiometric incorporation of red luminescent Eu III metal ions on the membrane of the ligand nanostructure. Firstly, a dual-emitting (blue and green) amphiphilic ligand molecule 1 was synthesized by connecting two units of blue emitting 4-triazolyl-2,6-bispyrazoScheme 1. Schematic representation of the formation of dual-emitting (blue and green) organic nanovesicles obtained from ligand 1 and an innovative route towards triple-color-emitting (blue, green and red) hybrid organic/ inorganic nanovesicles via coordination of Eu III ions on the membrane of the ligand vesicles in THF/water. The color-coded arrows indicate the corresponding emission colors.[a] Y.

Photonic Microrods Composed of Photoswitchable Molecules: Erasable Heterostructure Waveguides for Tunable Optical Modulation

“…Additionally, by utilizing the metal coordinating ability of bpp units available in L , luminescent metal ions can also be integrated on the surface of the microrods to create hybrid structures. [ 22,23 ] Experiments are underway in our lab to probe the modulation properties of this modulators implanted organic wave guide using infrared radiation. Raman Microscopy : Raman spectra of the samples were recorded on a Wi-Tec alpha 300 AR confocal Raman spectrometer equipped with a Peltier-cooled CCD detector.…”

Recent advances in the synthesis and applications of 2,6-dipyrazolylpyridine derivatives and their complexes

“…is the most common route for attaching additional functionality to the 1-bpp pyridine ring. 7,[33][34][35][36][37][38][39][40][41][42][43][44][45][46] Recently, however, 4-bromo-2,6-difluoropyridine has been identified as an alternative starting material for 4-substituted 1-bpp derivatives. The fluoro groups of this precursor are selectively displaced in eq 1 (X = F, Y = Br), 25 yielding a 4-bromo-1-bpp product that can be further modified by Sonogashira cross-coupling or substitution reactions.…”

“…The resultant assembly exhibits combined red/ blue/green/yellow emission. 34 Finally, a 1-bpp/fluorene copolymer that was assembled through multiple Sonogashira couplings 55 ( The most success has been achieved with complexes related to I, bearing thienyl substituents at either the 3-bpp ligand (R 1 ) or the terpy derivative (R 2 ). 53,121 Conjugation of the acceptor ligand to the thienyl group red-shifts the complexes' absorption across the full visible spectrum.…”

Organic Nanovesicular Cargoes for Sustained Drug Delivery: Synthesis, Vesicle Formation, Controlling “Pearling” States, and Terfenadine Loading/Release Studies

“…Although a plethora of block copolymer based vesicles are explored for drug delivery applications [5], vesicles from small biologically inspired designer molecules are rare. Earlier, we have found that aromatic rigid core 2,6-bispyrazolylpyridine (BPP) connected with long alkyl groups forms vesicles [12]. Hence for drug loading application the use of rigid molecules decorated with one of the base pairs found in DNA and RNA is a promising starting point to achieve nontoxic drug delivery systems.…”