Rapid Solid-Phase Synthesis of Oligo(1,4-phenylene ethynylene)s by a Divergent/Convergent Tripling Strategy

Huang, Shenlin; Tour, James M.

doi:10.1021/ja984138h

Cited by 80 publications

(58 citation statements)

References 15 publications

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“…The present self-assembly approach also provides a more facile preparation for an isolated molecular wire as compared to recently developed, interesting π-conjugated long molecules. [101][102][103] …”

Section: Self-assembly and Subsequent Polymerization Of Bola-form Monmentioning

confidence: 99%

Bottom-Up Synthesis and Morphological Control of High-Axial-Ratio Nanostructures through Molecular Self-Assembly

Shimizu

2003

Polym J

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ABSTRACT:Based on our recent results, the present paper overviews noncovalent formation of high-axial-ratio nanostructures (HARNs), such as fibers, rods, tubes and ropes, through molecular self-assembly of bola-form amphiphilic (bolaamphiphilic) monomers. A variety of bolaamphiphiles, in which sugars, peptides, or nucleobases as headgroups are connected to both ends of a hydrocarbon spacer, were newly designed and synthesized. Their self-assembling behavior was examined in aqueous solutions in terms of bottom-up fabrication of organic nanostructures. The morphologies proved to strongly depend on the headgroup structure, spacer chain lengths and even-odd carbon numbers of used oligo(methylene) spacers. Typical examples of self-assembled morphologies include nanofibers from 1-glucosamide-or thymidine-appended bolaamphiphiles, vesicle-encapsulated microtubes from glycylglycine-appended bolaamphiphiles, double-helical ropes from thymine-appended bolaamphiphiles. These self-assembled HARNs are constructed hierarchically in a manner similar to biological structures. On the basis of several solid-state analyses, molecular packing and orientation within the HARNs are discussed and compared with the single crystal structures in terms of hydrogen-bond networks. Furthermore, pH-dependent reversible polymer formation was achieved using the combination of glucuronamideand aromatic boronic acid-appended bola-form derivatives. Polymerization of bola-form 1-glucosamide derivatives with a 1,4-butadiyne group was performed in self-assembled nanometer-sized fibers, giving a single polydiacetylene chain of 64-mer that can be seen in TEM.KEY WORDS High-Axial-Ratio Nanostructure (HARN) / Bolaamphiphile / Self-Assembly / Noncovalent Synthesis / Hydrogen Bond / Nanofiber / Microtube / Nano-Rod / Rope / Hydrogel / Crystal Structure / Biomaterials possess highly organized non-covalent structures formed spontaneously in bottom-up fashion, 1 shaping natural body and functioning as energyconverting and information-converting materials. In contrast, conventional polymers are so-called linear macromolecules in which tens of thousands to millions of low-molecular-weight monomer units are connected to each other through covalent bonds. Very recently, a new family of polymers, including topologically complex polymers 2-13, 18-25 and self-assembled nanostructures, [14][15][16][17]26 has attracted much attention. 27,28 In particular, Kunitake and his co-worker built up the fundamental concept behind the polymolecular materials based on bilayer-containing molecular assemblies. 29,30 Stupp et al., 31, 32 Percec et al., 33 and Whitesides et al. 34,35 also succeeded in a molecule-up fabrication using polymer building blocks to realize nanometersized assemblies with well-defined shapes. The advantage of non-covalent self-assembly technique, unlike chemical reaction or polymerization, is in that it can directly produce ordered two-and three-dimensional structures like sheets, rods, fibers, tubes, disks, and spheres. It is more important that nanostruct...

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Section: Self-assembly and Subsequent Polymerization Of Bola-form Monmentioning

confidence: 99%

Bottom-Up Synthesis and Morphological Control of High-Axial-Ratio Nanostructures through Molecular Self-Assembly

Shimizu

2003

Polym J

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“…After repeating the reaction cycles, oligomeric arylacetylenes were obtained as final products. Huang and Tour applied a related sequence-specific methodology in solid-phase synthesis of linear, oligomeric arylacetylenes by subsequently introducing aryl diiodides and monoprotected phenylenebis[acetylenes] [16]. Bolton et al used Sonogashira coupling in the arylation of a polymer-bound olefinic acetylene prior to its Pauson -Khand cyclization [12].…”

mentioning

confidence: 99%

The Sonogashira Coupling of Polymer‐Supported Propargylamine with Aryl Iodides

Leikoski¹,

Kallonen²,

Yli‐Kauhaluoma³

2010

Helvetica Chimica Acta

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The Sonogashira coupling reaction of polymer-supported propargylamine (¼ prop-2-yn-1-amine) with aryl iodides in the presence of the [Pd(PPh 3 ) 2 ]Cl 2 /CuI catalyst system produces 3-arylprop-1-yn-1-amines smoothly at room temperature (Scheme). When propargylamine is attached on Wang resin through a carbamate linker, the common problems with amino functionality in palladium-catalyzed couplings are overcome. The arylpropynamines are cleaved from the polymer with CF 3 COOH and converted into chromatographically easily separable acetamides. Our solid-phase method opens a new pathway toward precursors of pharmacologically interesting arylpropynamines and arylpropanamines.Introduction. -Aryl-and heteroarylpropanes are common precursors of biologically important natural products, e.g., of lignin [1] and lignans [2]. In addition, some 3-aryl-or 3-heteroarylpropan-1-amine derivatives have been associated with central nervous system stimulating [3], antimalarial [4], positive inotropic [5], and antifungal [6] properties. We embarked on the solid-phase Sonogashira coupling reactions of polymer-bound propargylamine (¼ prop-2-yn-1-amine) with various aryl iodides. The 3-arylpropargylamines obtained in this coupling reaction can be reduced into 3-arylpropan-1-amines of interest. On the other hand, substituted arylpropargylamines themselves are interesting compounds since some of them, or their metabolites, possess selective inhibitory activity toward physiologically significant enzymes, such as aldehyde dehydrogenase [7] and monoamine oxidase B [8].The Sonogashira coupling is an efficient palladium-catalyzed method for constructing aryl-and heteroarylacetylenes [9]. This reaction has been widely studied in liquid-phase synthesis, and due to its general efficiency, e.g., high yields, tolerance of a wide range of functional groups, and a simple one-step procedure, it has in most applications replaced the analogous reaction of copper acetylide, the Castro -Stephens reaction [10]. Although the Sonogashira coupling in solid-phase reactions has been studied to a lesser extent, there are substantial amount of reports, where the benefits of the use of polymer-supported reagents have been combined with the high performance of this reaction [11 -24]. On the other hand, both the aryl iodide and the acetylene components have been successfully used as polymer-bound reactants. For example, Moore and co-workers generated a resin-bound terminal acetylene by deprotecting the trimethylsilyl group with Bu 4 NF, and subjected it to Sonogashira conditions with (trimethylsilyl)acetylene-funtionalized aryl iodides [11]. After repeating the reaction cycles, oligomeric arylacetylenes were obtained as final products. Huang and Tour applied a related sequence-specific methodology in solid-phase synthesis of linear,

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“…Actually, the gel permeation chromatography technique is generally expected to overestimate the molecular mass values of rigid, rod-like materials, owing to the difference of their hydrodynamic behaviour from that of the randomly coiled polystyrene polymers used as standards. [22] On the other hand, mass-discrimination phenomena are reported to occur, in particular at the Figure 2. MALDI-TOF mass spectrum of polymer 6 obtained with Pd 2 (dba) 3 /AsPh 3 as catalyst higher molecular mass end, in the MALDI-TOF spectra of polydisperse polymers (polydispersity Ͼ 1.1), and this drawback may result in substantially underestimated molecular mass values calculated on the basis of these mass spectra for such polymers.…”

Section: Model Polymerization Processmentioning

confidence: 99%

A General Strategy for the Synthesis of Conjugated Polymers Based upon the Palladium-Catalysed Cross-Coupling of Grignard Reagents with Unsaturated Halides

Babudri¹,

Colangiuli²,

Farinola³

et al. 2002

Eur. J. Org. Chem.

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Rapid Solid-Phase Synthesis of Oligo(1,4-phenylene ethynylene)s by a Divergent/Convergent Tripling Strategy

Cited by 80 publications

References 15 publications

Bottom-Up Synthesis and Morphological Control of High-Axial-Ratio Nanostructures through Molecular Self-Assembly

Bottom-Up Synthesis and Morphological Control of High-Axial-Ratio Nanostructures through Molecular Self-Assembly

The Sonogashira Coupling of Polymer‐Supported Propargylamine with Aryl Iodides

A General Strategy for the Synthesis of Conjugated Polymers Based upon the Palladium-Catalysed Cross-Coupling of Grignard Reagents with Unsaturated Halides

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