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Highly π-extended butterfly-shaped triarylamine dyads with aryleneethynylene spacer were constructed using an efficient synthetic route. These aryleneethynylene-bridged dyads are highly fluorescent and exhibited high HOMO levels, and low bandgaps, which a

New luminophores having different aryl nuclei and propynones moieties have been obtained via Sonogashira reactions. Their optical properties were evaluated and indicated that carbonyl groups are responsible for significant bathochromic effects and high St

The synthesis of a novel sugar coated poly(p-phenyleneethynylene) (PPE) via Pd-catalyzed Sonogashira reaction and its subsequent interaction with concanavalin A (Con A) are described. UV-Vis and fluorescence spectra were employed to investigate the respon

In this paper, a novel phenyleneethynylene derivative 4,4′-(2,5-dimethoxy-1,4-phenylene)bis(ethyne-2,1-diyl) dibenzoic acid (p-acid) and its derivative p-acid-Br were synthesized. Infrared spectroscopy (IR), fluorescence (FL) spectroscopy and ultraviolet

We have an ongoing interest in the design and control of helical conformation of water-soluble meta-linked poly(phenylene ethynylene)s (PPEs) and the further development of novel functional materials. Four cationic meta-linked PPEs (P1′-P4′) were synthesized to study the influence of differences in the backbone and side chain structure on their conformations. For P1′ and P4′ without side chains on the para-phenylene units, fluorescence spectroscopic investigations indicated obvious intramolecular helical folding, whereas for P2′ and P3′ with nonpolar and polar side chains on the para-phenylene units respectively, a significantly different conformational mode, namely, cofacial intermolecular aggregation was suggested. The side chains on the para-phenylene units of P2′ and P3′ may be located in the interior cavity of helix and induce steric effect on the formation of helix. However, the introduction of 2,1,3-benzothiadiazole (BT), a low energy gap unit, into the backbone of P4′ showed little influence on the formation of helix despite its larger and more rigid structure than the phenylene unit. Thus, the light emission of these polymers can be tuned in the range from blue, green to yellow with the changes of conformational modes. Moreover, the functionalization of multi-walled carbon nanotubes (MWCNTs) by P4′ in methanol and water, and by using its neutral precursory polymer P4 in tetrahydrofuran was explored through transmission electron microscopy and fluorescence spectroscopy. P4′ was directly observed to individualize MWCNT by forming a monolayer helical wrapping on the nanotube surface, which may be attributed to the backbone flexibility of meta-linked PPE and the strong π?π interactions between the PPE backbone and the CNT surface. Moreover, P4′ served as a better dispersing agent for MWCNT than P4, suggesting that the cationic side groups may act as solubilizing groups which also separated the individual nanotubes because of charge repulsion.

Fluorescent conjugated polytriazoles (FCP 1-4) containing both 2,5-diphenyl-1,3,5-oxadiazole (OXD) and 1,2,3-triazole moieties in the main chain were synthesized from aromatic diazide (1) and dialkynes (2-5) via click polymerization, respectively. In the polymers, OXDs (fluorophores) and triazole rings (generated via CuAAC acting as metal ion ligands) comprise a fluorescent system. The polytriazoles displayed relatively strong emission with quantum yields in the range of 0.20-0.28 at room temperature in DMF. The study on their ion-responsive properties showed that, although all four FCPs have good selectivity for Ag+, the integration of alkoxy side groups (methoxy for FCP 2, hexyloxy for FCP 3 and 2-ethylhexyloxy for FCP 4) to the main chains of the polytriazoles decreased their sensitivity for Ag+via alteration of the polymer aggregation status and electron density of the main chains. Thus FCP 1 is highly sensitive for Ag+, where its Ksv is as high as 1.44 × 105 M-1 and its lowest detection limit is in the ppb range (4.22 × 10-7 M). This study provides an efficient click approach to the synthesis of a novel fluorescence sensor for Ag+ detection, which could expand the application of click polymerization in designing fluorescence sensors based on the triazole unit. This journal is

A substituted fullerene was incorporated into a PPE-conjugated polymer repeat unit. This subunit was then polymerized via Sonogashira coupling with other repeat units to create polymeric systems approaching 50 repeat units (based on GPC characterization).

Remarkably enhanced stability of the self-assembled hydrogen-bonded heterocapsule 1×2 by the encapsulation of 1,4-bis(1-propynyl)benzene 3 a was found with Ka=1.14×109 M-1 in CDCl3 and Ka2=1.59×108 M-2 in CD3OD/CDCl3 (10 % v/v) at 298 K. The formation of 3 a(1×2) was enthalpically driven (ΔH°0 and ΔS°0) and there was a unique inflection point in the correlation between ΔH° versus ΔS° as a function of polar solvent content. The ab initio calculations revealed that favorable guest-capsule dispersion and electrostatic interactions between the acetylenic parts (triple bonds) of 3 a and the aromatic inner space of 1×2, as well as less structural deformation of 1×2 upon encapsulation of 3 a, play important roles in the remarkable stability of 3 a(1×2). Copyright

Noncovalent interactions, especially hydrogen-bonding interactions as well as electrostatic forces, confined within one macromolecule are the key to designing foldamers that adopt well-defined conformations in solution. In the context of significant recent activities in the area of triazole-connected foldamers, so-called clickamers, we present a fundamental study that compares various model compounds that bear adjacent N-, O-, or F-heteroatom substituents. The interplay of attractive and repulsive interactions leads to rotational constraints around the single bonds attached to both the 1- and 4-positions of the 1,2,3-triazole moiety and should therefore be able to induce well-defined conformational preferences in higher oligomers and polymers, that is, foldamers. Various compounds were synthesized and characterized with regard to their preferred conformations in all three aggregation statesa-that is, in the gas phase, in solution as well as in the solid statea-by employing DFT calculations, NMR spectroscopic experiments, and X-ray crystallography, respectively. On the basis of the thus-obtained general understanding of the conformational behavior of the individual connection motifs, heterostructures were prepared from different motifs without affecting their distinct folding characteristics. Therefore, this work provides a kind of foldamer construction kit, which should enable the design of various clickamers with specific shape and incorporated functionality. A foldamer construction kit: Various heterostructures "clicked" together by structure-directing triazole moieties were investigated with regard to their conformational behavior. Different heteroatoms (X; see graphic) can be used to bias the conformation around the N(1)- and C(4)-connecting single bonds of the triazoles based on tunable noncovalent interactions.

To introduce crown ethers into the struts of metal - organic frameworks (MOFs), general approaches have been developed for the syntheses of dicarboxylic acid dibenzo[30]crown-10 (DB30C10DA), dicarboxylic acid di-2,3-naphtho[30] crown-10 (DN30C10DA), dicarboxylic acid bisparaphenylene[34]crown-10 (BPP34C10DA), and dicarboxylic acid 1, 5-naphthoparaphenylene[36]crown-10 (NPP36C10DA). These novel crown ethers not only retain the characteristics of their parent crown ethers since they can 1) bind cationic guests and 2) serve as templates for making mechanically interlocked molecules (MIMs), such as catenanes and rotaxanes, but they also present coordination sites to connect with secondary building units (SBUs) in MOFs. The binding behavior of BPP34C10DA with 1,1′-dimethy 1-4, 4′-bipyridinium bis(hexafluorophosphate) (DMBP·2PF6) has been investigated by means of UV/ Vis, fluorescence, and NMR spectroscopic techniques. The crystal superstructure of the complex DMBP·2PF6C BPP34C10DA was determined by X-ray crystallography. The NPP36C10DA-based [2]catenane (H 2NPP36C10DC·CAT4PFfi) and the BPP34C10DA-based [2]catenane (H2BPP34C10DC-CAT-4PF6) were prepared in DMF at room temperature by the template-directed clipping reactions of the planarly chiral NPP36C10DA and BPP34C10DA with 1, 1′-[1,4-phenylenebis(methylene)]di4, 4′-bipyridin-l-ium bis(hexafluorophosphate) and 1,4-bis(bromomethyl) benzene, respectively. The crystal structure of the dimethyl ester (BPP34C10DE-CAT·4PF6) of the [2]catenane H 2BPP34C10DC-CAT·4PF6 was investigated by X-ray crystallography, which revealed racemic R and S isomers with planar chirality present in the crystal in a 1:1 ratio. These crown ether based struts serve as excellent organic ligands to bind with transition metal ions in the construction of MOFs: the crown ethers BPP34C10DA and NPP36C10DA in the presence of Zn(NO3)2·4H2O afforded the MOF-1001 and MOF-1002 frameworks, respectively. The crystal structures of MOF-1001 and MOF-1002 are both cubic and display Fm3m symmetry. The unit cell parameter of the metal - organic frameworks is α= 52.9345 A. Since such MOFs, containing electron-donating crown ethers are capable of docking incoming electronaccepting substrates in a stereoelectronically controlled fashion, the present work opens a new access to the preparation and application of MOFs.

(Chemical Equation Presented) A new set of aryleneethynylene derivatives bearing three, four, and six p-carboranes as potential wheels attached to a semirigid chassis have been designed and synthesized. These molecules are expected to move in predetermined patterns on atomically smooth surfaces, depending on their specific configuration.

A series of 1,4-diethynylbenzene (1) derivatives, H-C≡C-R-C≡C-H with R = C6H3NH2 (2), C6H3F (3), C6H2F2-2,5 (4), C6F4 (5), C6H2/

Several second generation memory components consisting of oligo(phenylene ethynylene)s containing easily reducible functionalities consisting of either nitro or quinone cores have been synthesized for incorporation into molecular electronic devices. Addit

Syntheses are described for the preparation of a variety of diynes which are converted to high molecular weight substituted arylenebuta-1,3-diynylene polymers by oxidative coupling and to high molecular weight substituted arylene-ethynylene polymers by Pd(II) catalysed cross coupling reactions. The products tend to be insoluble in normal organic solvents. Doping with ferric chloride produces significant changes in conductivity but these are less than those produced on equivalently substituted thienylene-phenylene polymers.

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