Synthesis and Properties of the Longest Oligothiophenes:  The Icosamer and Heptacosamer

Nakanishi, Hiizu; Sumi, Naoto; Aso, Yoshio; Otsubo, Tetsuo

doi:10.1021/jo981541y

Cited by 108 publications

(78 citation statements)

References 27 publications

(24 reference statements)

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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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“…Well-ordered and crystalline oligothiophenes are currently being investigated for optoelectronic applications especially in the form of molecular wires [73][74][75][76] using raw as well as alkylsubstituted forms including 16-, 20-, and 27-mers. Besides crystalline oligothiophenes, amorphous oligothiophenes [76,77] have also been used in several devices as reported in published literature [73,75,[78][79][80][81][82][83].…”

Section: Organic Molecules For Device Applicationsmentioning

confidence: 99%

Organic semiconductors for device applications: current trends and future prospects

Ahmad

2014

Journal of Polymer Engineering

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Abstract:With the rich experience of developing silicon devices over a period of the last six decades, it is easy to assess the suitability of a new material for device applications by examining charge carrier injection, transport, and extraction across a practically realizable architecture; surface passivation; and packaging and reliability issues besides the feasibility of preparing mechanically robust wafer/substrate of single-crystal or polycrystalline/ amorphous thin films. For material preparation, parameters such as purification of constituent materials, crystal growth, and thin-film deposition with minimum defects/ disorders are equally important. Further, it is relevant to know whether conventional semiconductor processes, already known, would be useable directly or would require completely new technologies. Having found a likely candidate after such a screening, it would be necessary to identify a specific area of application against an existing list of materials available with special reference to cost reduction considerations in large-scale production. Various families of organic semiconductors are reviewed here, especially with the objective of using them in niche areas of large-area electronic displays, flexible organic electronics, and organic photovoltaic solar cells. While doing so, it appears feasible to improve mobility and stability by adjusting π-conjugation and modifying the energy bandgap. Higher conductivity nanocomposites, formed by blending with chemically conjugated C-allotropes and metal nanoparticles, open exciting methods of designing flexible contact/interconnects for organic and flexible electronics as can be seen from the discussion included here.

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“…The electronic system is potentially attractive in view of structural analogy to that of ( [18]annuleno) 3 [30]annulenes.…”

Section: Sbfmentioning

confidence: 99%

“…17 A series of long discrete oligothiophene molecules were synthesized by Otsubo and co-workers, which culminated in the synthesis of a discrete 27-mer in 1998. 18 Diederich et al reported the synthesis of oligo-enediyne derivatives in 1999 and the molecular length of the longest one reached 11.9 nm with 16 repetitive units. 19 Synthetic challenges to explore a discrete functional molecule with well-defined structures far beyond these achievements have continued after 2000.…”

Section: Introductionmentioning

confidence: 99%

Exploration of Giant Functional Porphyrin Arrays

Aratani

Osuka

2014

Bulletin of the Chemical Society of Japan

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Directly linked linear porphyrin arrays were synthesized and their photophysical properties depending on the length of the arrays were investigated. Ag(I)-promoted oxidative coupling of 5,15-diaryl Zn(II) porphyrins has proven to be effective for preparations of very long mesomeso-linked Zn(II) porphyrin arrays (Zn). A stepwise doubling strategy with strict purification at each doubling step allowed for preparation of gigantic but discrete linear arrays in an unprecedented manner. Large cyclic porphyrin wheels were also synthesized by final mesomeso coupling intramolecular cyclization. Crucial to this success are high reactivity and high regioselectivity of the Ag(I)-promoted oxidative coupling. Equally important are high solubilities of Zn despite their large molecular weights, which arise from their perpendicularly linked structures. Another advantage of this doubling strategy is a large difference in the molecular weights among reactants and products that increases as the reactant array becomes larger, allowing separation of coupling products by preparative GPC-HPLC. As an alternative protocol, Pd-catalyzed SuzukiMiyaura cross-coupling has been extensively used for synthesis of cyclic porphyrin arrays. This strategy gave novel linear and cyclic porphyrin arrays from β-borylated porphyrins that were prepared by Ir-catalyzed borylation of meso-free porphyrins. As an interesting example, a porphyrin nanotube consisting of four porphyrins doubly bridged by 2,6-pyridinylene spacers was synthesized and revealed to possess a C 60 -encapsulation capability. Exciton coupling, effective energy hopping, coherent length, and excitation energy transfer of mesomeso-linked linear and cyclic porphyrin arrays are discussed. STM and AFM detections of the large porphyrin arrays are also presented. We believe that these studies expand the range of organic molecules we can manipulate and open a door to a new area of nanoscaled and sub-microscaled functional porphyrin materials.

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Synthesis and Properties of the Longest Oligothiophenes: The Icosamer and Heptacosamer

Cited by 108 publications

References 27 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

Organic semiconductors for device applications: current trends and future prospects

Exploration of Giant Functional Porphyrin Arrays

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