Browsing by Subject "Click chemistry"

Now showing 1 - 6 of 6

Open Access
Biocompatible supramolecular catalytic one-dimensional nanofibers for efficient labeling of live cells
(American Chemical Society, 2015) Khalily, M. A.; Gulseren, G.; Tekinay, A. B.; Güler, Mustafa O.
Understanding complex cellular functions requires study and tracking of biomolecules such as proteins, glycans, and lipids in their natural environment. Herein, we report the first supramolecular nanocatalyst for bioorthogonal click reaction to label live cells. This biocompatible and biodegradable nanocatalyst was formed by self-assembled peptide nanofibers complexed with copper ions. The supramolecular nanocatalyst enhanced azide-alkyne cycloaddition reaction rate under physiological conditions and was shown to be useful for efficient bioorthogonal labeling of live cells.
Open Access
In situ preparation of thermoset/clay nanocomposites via thiol-epoxy click chemistry
(Springer Verlag, 2018) Purut, Koc, O.; Bekin, Acar, S.; Uyar, Tamer; Tasdelen, M. A.
A series of thermoset/clay nanocomposites are prepared by thiol-epoxy click reaction using commercially available starting compounds at ambient conditions in very good yields. The incorporation and exfoliation of clay nanolayers in the thermoset matrix are confirmed by FT-IR, XRD and TEM analyses. The influence of clay loadings on the thermal and mechanical analyses is investigated and all nanocomposites exhibit improved properties than that of the pristine thermoset. The nanocomposite containing 1% montmorillonite by weight has the most improved mechanical properties due to its highly exfoliated structure resulting in efficient interactions between clay and polymer matrix. A further increase of the clay loading results in the aggregation of clay plates to form intercalated structures leading to deteriorated thermal and mechanical properties of nanocomposites.
Open Access
Optimization of orthogonal reactions on bodipy dyes for one-pot synthesis of light harvesting dendrimers
(2013) Bekdemir, Ahmet
For more than a decade, synthetic organic chemistry has dealt with focusing on highly selective and efficient reactions that can proceed under mild conditions which would then be categorized under the term “orthogonal click chemistry”. These types of reaction have served number of applications for years as in peptide synthesis, homogeneous catalysis and development of supramolecular systems. On the other side, after a partial understanding of how photosynthetic bacteria and plants harvest solar radiation in order to carry their necessary carbon dioxide reduction reaction by converting light to chemical energy, artificial light harvesting systems have captivated a lot attention of scientists. Because today’s one of the biggest and inevitable problems is to discover/invent alternative energy sources/devices for future demands, these artificial light harvesting and solar concentrator systems are highly open for further development and optimization. However, like most other macromolecular systems, synthesis of these kind of devices should be straightforward so as to decrease the cost and to increase the efficiency. At this point, orthogonal click reactions, being mild and efficient synthetic models, can undoubtedly be worthwhile to consider as proper tools for easy preparation of light harvesting molecules. Here we propose a synthesis of thiol, Michael accepting groups, amine and isothiocyanate modified BODIPY dyes for light harvesting cascade preparation. Moreover, the optimization of Michael addition type thiol – ene reaction of these functionalized dyes has been discussed. Among methyl methacrylate, cyanoacetic acid and nitroolefin functionalizations, it was found that nitroolefin attached BODIPY dyes are the most reactive one. The achieved product has been investigated in terms of fluorescence and energy transfer.
Open Access
Polyhedral oligomeric silsesquioxane-based hybrid networks obtained via thiol-epoxy click chemistry
(Springer, 2017) Bekin Acar, S.; Ozcelik, M.; Uyar, Tamer; Tasdelen, M. A.
A series of hybrid networks based on polyhedral oligomeric silsesquioxane (POSS) were prepared by thiol-epoxy click reaction using commercially available octakis-glycidyl-POSS (G-POSS), trimethylolpropane triglycidyl ether, and trimethylolpropane tris(3-mercaptopropionate) as monomers. The click reaction was simply catalyzed by lithium hydroxide which proceeded readily at ambient conditions in very good yields. The incorporation of G-POSS into the network was clearly determined by transmission electron microscopy, FTIR, and 1H-NMR spectroscopy techniques performed with a model study using 1-butane thiol and G-POSS molecules. The homogeneous distribution of G-POSS up to 5 wt% in the hybrid network was apparently confirmed by morphological investigations. By increasing G-POSS content higher than 5 wt%, the heterogeneous dispersion of G-POSS was determined from the tensile strength measurements. The significant decrease in tensile strength was possible due to the agglomeration of G-POSS. On the other hand, thermal properties of hybrid networks were compared together by thermogravimetric analyses, where all samples exhibited one-step degradation in the range of 220–500 °C. The thermal decomposition of hybrid network led to complete degradation of the organic part and favored the formation of stable carbonaceous and inorganic residues as char. Thus, the char yields of hybrid networks were increased to 6.2, 7.8, 10.1, 12.7, and 15.1% by G-POSS loadings from 0 to 15 wt%. This improvement was also a proof of the incorporation of G-POSS into the hybrid networks that resulted in high heat-resistant POSS-based hybrid networks compared to a sample without G-POSS.
Open Access
Supramolecular assemblies constructed by cucurbituril-catalyzed click reaction
(2011) Tuncel, D.; Ünal, Ö.; Artar, M.
Cucurbituril homologues are multi-functional macrocycles that can find applications in many areas and have numerous interesting features setting them apart from the other macrocycles. Among them, the ability of one of the cucurbituril homologues, cucurbit[6]uril (CB6), to catalyze 1,3- dipolar cycloaddition in a regiospecific fashion is truly exceptional. Using this feature, small molecules can be clicked together to form complex structures in a very efficient way. Accordingly, in this article we review recent research involving the use of CB6-catalyzed 1,3-dipolar cycloaddition or the click reaction of CB6 in the construction of supramolecular assemblies including rotaxanes, pseudorotaxanes, polyrotaxanes, polypseudorotaxanes, molecular switches, machines, and nanovalves.
Open Access
Synthesis and characterization of cross-linked water-dispersible conjugated polymer nanoparticles
(2012) Ekiz, Şeyma
In this study, a novel synthetic method was demonstrated for the water-dispersible crosslinked light-emitting conjugated polymer nanoparticles with enhanced stability. In order to synthesize the novel conjugated polymer nanoparticles, thiophene-based monomers were synthesized with different functional groups such as bromine, hydroxyl and azide groups. These monomers were characterized by 1H-NMR spectroscopy. After the synthesis of the monomers, various polymers were synthesized via Suzuki coupling and oxidative polymerization. Their structural and optical properties were fully characterized by spectroscopic techniques such as 1H-NMR spectroscopy, FT-IR spectroscopy and Gel Permeation Chromatography (GPC). Finally, crosslinked conjugated polymer nanoparticles were synthesized by a diaminoalkyne crosslinker and various useful functional groups were introduced to the nanoparticles such as triazoles and amine groups. Incorporation of the hydrophilic functional groups to the conjugated polymer nanoparticles resulted with patchy, janus-like nanoparticles. CB6 was used as a catalyst for the first time in nanoparticle synthesis for 1,3-azide alkyne Huisgen cycloaddition which formed a conjugated polymer-based nanosized rotaxanes. Crosslinking of the conjugated polymer nanoparticles was also achieved by the irradiation of the nanoparticles under UV light in order to get shape-persistent nanoparticles. Various functional groups of the conjugated polymer nanoparticles make them highly versatile for biological studies such as cell imaging and drug delivery in biological systems. Synthesized nanoparticles were fully characterized by dynamic light scattering (DLS) measurement, transmission electron microscopy (TEM), FT-IR spectroscopy and UV-Vis spectroscopy.