Highly Unsaturated Oligomeric Hydrocarbons: α‐(Phenylethynyl)‐ω‐phenylpoly[1,2‐phenylene(2,1‐ethynediyl)]

Grubbs, Robert H.; Kratz, Detlef

doi:10.1002/cber.19931260123

Cited by 111 publications

(65 citation statements)

References 25 publications

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“…Phenylene ethynylene (PE) polymers are of interest owing to their unique photophysical properties, supramolecular organization, and conformational diversity. [1,2] Their structures include rigid parasubstituted polymers, [3] oligomers and macrocycles [4,5] as well as more conformationally flexible meta- [6,7] and ortholinked [8,9] molecules. Polymeric para-derivatives have been characterized with respect to their optical properties and, more recently, their liquid-crystalline organization.…”

Section: Introductionmentioning

confidence: 99%

“…[13] Single-crystal structures of ortho-substituted oligomers indicate the adoption of a helical conformation with a helical repeat of three aromatic rings. [8] The study of facially amphiphilic (FA) molecules in which the side chains attached to the backbone are polar (P) and nonpolar (NP) has been more limited. [14][15][16][17]7] However, our research group has recently reported structures in which the PE backbone was patterned with P cationic and NP alkyl groups that project from opposite sides of the extended structures.…”

Section: Introductionmentioning

confidence: 99%

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Self‐Assembled Structures with Liquid‐Crystalline Order in Aqueous Solution by Patterning Poly(phenylene ethynylene)s

Kim

Arnt

Atkins

et al. 2006

Chemistry A European J

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Facially amphiphilic (FA) phenylene ethynylene (PE) polymers that self-assemble in aqueous solution were studied by small-angle X-ray diffraction (SAXD) and found to self-assemble into bilayers with a fully extended backbone. The resulting bilayers have long-range liquid-crystalline order. This self-assembly is programmed into the molecule by placing polar and nonpolar groups at precise locations so that they segregate onto opposite sides of the molecular structure. The absence of FA patterning generated an amorphous sample confirming the importance of this programmed amphiphilicity in the self-assembly process. Facially amphiphilic patterning represents a new design criterion for supramolecular chemistry, illustrated here in the observation of molecular ordering into bilayers reminiscent of self-assembled structures commonly found in biology, including amphiphilic beta-sheet polypeptides and phospholipid bilayers.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Self‐Assembled Structures with Liquid‐Crystalline Order in Aqueous Solution by Patterning Poly(phenylene ethynylene)s

Kim

Arnt

Atkins

et al. 2006

Chemistry A European J

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“…2). The monomer bridging group, X, affects the thermodynamics of the polymerization, for example, the polymerization of 1,2,4,5-tetrakis(phenylethynyl)benzene [35] and poly(arylene-1,2-ethynylene), [36] each containing four acetylene linkages, gave a DSC-measured -DH = 121.3 kJ mol -1 of alkyne upon thermal polymerization, whereas the thermolysis of 1-5 gave -DH = 110.9, 103.8, 112.3, 104.6, and 107.5 kJ mol -1 of alkyne, respectively.…”

Section: Boda Polymerizationmentioning

confidence: 99%

“…material or a different enediyne, chain addition to the starting material to propagate a polymer, coupling with other radical species, or termination by atom abstraction from protic or halogenated sources. [24][25][26] The application of the Bergman cyclization to prepare thermally stable linear poly(phenylenes) and polynaphthalenes by the thermolysis of substituted enediynes and 1,2-dialkynylbenzenes has been reported in recent years, [11,14,35,36] although the most thorough structural investigation of these polymerizations indicate that the products are not simply polynaphthalenes but rather more complex copolymers of naphthalenyl, five-membered fulvenyl structures, and possibly polyacetylenyl repeat units. [37] The polymerization of BODA monomers leads to crosslinked network versions of these polymers (Scheme 2 illustrates the idealized polynaphthalenyl structure for clarity of the branching scheme, although the actual backbones are probably more akin to the poly(naphthalene-co-benzofulvene) structure illustrated in Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Polyarylene Networks via Bergman Cyclopolymerization of Bis‐ortho‐diynyl Arenes

Smith¹,

Shah²,

Perera³

et al. 2007

Adv Funct Materials

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Bis‐ortho‐diynylarene (BODA) monomers, prepared from common bisphenols in three high yielding steps, undergo free‐radical‐mediated thermal polymerization via an initial Bergman cyclo‐rearrangement. Polymerization is carried out at 210 °C in solution or neat with large pre‐vitrification melt windows (4–5 h) to form branched oligomers containing reactive pendant and terminal aryldiynes. Melt‐ and solution‐processable oligomers with weight‐average molecular weight Mw = 3000–24 000 g mol–1 can be coated as a thin film or molded using soft lithography techniques. Subsequent curing to 450 °C affords network polymers with no detectable glass transition temperatures below 400 °C and thermal stability ranging from 0.5–1.5 % h–1 isothermal weight loss measured at 450 °C under nitrogen. Heating to 900–1000 °C gives semiconductive glassy carbon in high yield. BODA monomer synthesis, network characterization and kinetics, processability, thin‐film photoluminescence, and thermal properties are described.

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“…Consequently, the pyridyl rings rotate outward by 180° to form a polymer chain with the rhodium dimer bridging adjacent ligands in a zig-zag fashion. This polymer is a supramolecular analogue of the hitherto unknown ortho-PPE 7 and as such is a fascinating structure. The Rh-N distance within the polymer is 2.25 Å, typical for Rh-N bonds in such systems.…”

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confidence: 99%

Three unique coordination geometries involving 1,2-dimethoxy-4,5-bis(2-pyridylethynyl)benzene

et al. 2001

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Reaction of the new ligand 1,2-dimethoxy-4,5-bis(2-pyridylethynyl)benzene with different metal centers under similar reaction conditions led to three distinct structure formation processes: molecular ring closure, dimerization, and polymer formation.In synthetic, covalent organic chemistry the notion of conformers, oligomers and polymers are distinctly separated and irreconcilable. In supramolecular synthesis on the other hand this conception is less stringent. The utilized building blocks and the variety of binding forces that hold supramolecular assemblies together by arranging organic modules in the solid state makes the border of the very notions of conformers, cycles, and polymers more permeable. Here we wish to demonstrate that one organic module 1,2-dimethoxy-4,5-bis(2-pyridylethynyl)benzene 1 1 can form a supramolecular cycle, a dimer and polymer utilizing different inorganic connectors Cu(OAc) 2 , CoCl 2 and [Rh(OAc) 2 ] 2 .Single crystals suitable for X-ray diffraction † of Cu (1) O (maintaining the ligand to metal ratio) and ethanol was substituted for methanol (40% yield). These three systems each form a distinctly different structure and between them, demonstrate the importance of the free rotation of the pyridyl rings around the carbon-carbon bonds for facilitating the formation of the three structure types.Compound 2 demonstrates the preference of Cu 2+ for square planar coordination with copper positioned snugly between the two pyridyl rings. The resulting N-Cu-N (Cu-N 2.01 Å, NCu-N 172.98°) bonds close an eleven membered, triangular ring (Fig. 1), which is nearly identical to the structures reported by Bosch and Barnes for 1,2-bis(2-pyridylethynyl)benzene. 2 The square planar coordination of copper is completed by two trans oxygens from separate acetate groups.Compound 3 contains Co 2+ , which is found in typical tetrahedral coordination. 3 This tetrahedral preference, apparently, cannot be conveniently satisfied through a ring closure that would require a rotation of the pyridyl rings away from the 180° angle found in the copper complex. The result of such a rotation would be an elongated Co-N bond. Instead, the pyridyl rings rotate away from each other by 128° and bind to separate cobalt atoms with bond lengths of 2.03 Å, which is typical for Co-N bonds. The tetrahedral coordination in each case is completed by two chlorine atoms. The overall structure (Fig. 2) consists of two molecules of 1 bridging two cobalt atoms. An inversion center is located in the middle of the dimer.The polymeric structure of 4 (Fig. 3) results from the linear coordination preference of [Rh(OAc) 2 ] 2 . The structure consists This journal is

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Highly Unsaturated Oligomeric Hydrocarbons: α‐(Phenylethynyl)‐ω‐phenylpoly[1,2‐phenylene(2,1‐ethynediyl)]

Cited by 111 publications

References 25 publications

Self‐Assembled Structures with Liquid‐Crystalline Order in Aqueous Solution by Patterning Poly(phenylene ethynylene)s

Self‐Assembled Structures with Liquid‐Crystalline Order in Aqueous Solution by Patterning Poly(phenylene ethynylene)s

Polyarylene Networks via Bergman Cyclopolymerization of Bis‐ortho‐diynyl Arenes

Three unique coordination geometries involving 1,2-dimethoxy-4,5-bis(2-pyridylethynyl)benzene

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