Comparison of “Polynaphthalenes” Prepared by Two Mechanistically Distinct Routes

Johnson, J. P.; Bringley, Dustin A.; Wilson, Erin E.; Lewis, Kevin D.; Beck, Larry W.; Matzger, Adam J.

doi:10.1021/ja035695t

Cited by 52 publications

(44 citation statements)

References 12 publications

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“…The existence of benzofulvenes is assumed in the polymer as well, as they are very difficult to distinguish from the naphthalene absorbance bands and are seen in similar polymers. [37] Fluorocarbon vibrations in the vicinity of 1253 cm -1 remain consistently the largest in both the monomer and polymer spectra of 1. The IR spectra for all BODA derived polymer networks are completely void of bands indicative of aliphatic or olefinic linkages, though they are seen in similar polymers derived from thermal polymerization of 1,2-ethynyl benzenes.…”

Section: Network Polymer Characterizationmentioning

confidence: 89%

“…[47][48][49] Radical polymerization of 1,2-dialkynyl arenes below 100°C (depending on substitution) yields what are often called "polynaphthalene" structures that have recently been shown to have a more complicated polymer backbone. [37] Tetraphenyl pendant substitution in BODA monomers provides large melt processing windows ranging from 4-5 h at 210°C as found by dynamic mechanical spectroscopy. [24][25][26] Exothermic polymerization of BODA monomers 1-5 in the melt are detected by differential scanning calorimetry (DSC, 10°C min -1 ) at 200-210°C, giving thermal reaction profiles consistent with known phenyl substituted arenediynes (Fig.…”

Section: Boda Polymerizationmentioning

confidence: 96%

“…This intense coloring seen in all poly(arenediyne)s has been shown to support the chemical distinctness of these polymers from polynaphthalene proper, which has a paler ivory color because of very little orbital overlap between monomer units. [37,56] …”

Section: Optical Properties and Luminescencementioning

confidence: 99%

“…[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). The intrinsically branched architecture resulting from the tetra-functionality of BODA monomers leads to oligomers with excellent melt and solution processability, which can be utilized in molding and coating applications prior to final cure.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Network Polymer Characterizationmentioning

confidence: 89%

Section: Boda Polymerizationmentioning

confidence: 96%

Section: Optical Properties and Luminescencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Smith¹,

Shah²,

Perera³

et al. 2007

Adv Funct Materials

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“…[7] Since helical chirality endows polynaphthalenes with excellent resistance to racemization and renders them potential for asymmetric catalysis and enantioselective separation, we brought up the idea of incorporating chiral imides into a series of enediynes. Based on our previous work, long alkyl or alkoxyl groups were incorporated to maintain a good solubility of the rigid conjugative monomers and polymers.…”

Section: Introductionmentioning

confidence: 99%

Bergman Cyclization in Polymer Chemistry and Material Science

Xiao

2011

Macromol. Rapid Commun.

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Bergman cyclization of enediynes, regarded as a promising strategy for anticancer drugs, now finds its own niche in the area of polymer chemistry and material science. The highly reactive aromatic diradicals generated from Bergman cyclization can undergo polymerization acting as either monomers or initiators of other vinyl monomers. The former, namely homopolymerization, leads to polyphenylenes and polynaphthalenes with excellent thermal stability, good solubility, and processability. The many remarkable properties of these aromatic polymers have further endowed them to be manufactured into carbon-rich materials, e.g., glassy carbons and carbon nanotubes. Whereas used as initiators, enediynes provide a novel resource for high molecular weight polymers with narrow polydispersities. The aromatic diradicals are also useful for introducing oligomers or polymers onto pristine carbonous nanomaterials, such as carbon nano-onions and carbon nanotubes, to improve their dispersibility in organic solvents and polymer solutions.

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Unusual Cyclizations

Gilmore

Alabugin

2012

Encyclopedia of Radicals in Chemistry, Biology and Materials

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Although many radical cyclizations play prominent roles in organic synthesis and an ever increasing body of fundamental information aids in the constant development of new radical processes, a number of cyclization modes remain underrepresented. Such “unusual” gaps in the arsenal of available transformations exist for a variety of ring sizes. For example, even fast and stereoelectronically favorable 3‐exo and 4‐exo cyclizations are often rendered impossible by the high thermodynamic cost for the formation of strained small cycles. In contrast, 5‐endo cyclizations are exothermic but disfavored stereoelectronically and often slow. Moreover, even the most common five‐ or six‐membered rings are often made via an unusual class of cycloaromatization reactions where radical formation from a nonradical precursor is coupled with the cyclization step. A new set of problems appears for the formation of larger rings where the cyclizations are disfavored entropically. Additionally, certain factors disfavor even the well‐represented cyclization topologies, independent on the ring size. In particular, most cyclic closures involve carbon‐carbon bond formation via carbon radical addition to an alkene or alkyne, whereas radical ring closure via the formation of C‐heteroatom bonds are relatively scarce. We expand our discussion to radical cyclizations that proceed via CO and CN bond formation, which often provide an efficient approach to the construction of heterocycles. In our discussion, we highlight a number of factors that are useful for promoting unusual cyclizations: destabilization of reactants, stabilization of the cyclic products, electronic and conformational effects on the transition states, as well as coupling of thermodynamically unfavorable events with highly exothermic follow‐up steps.

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Comparison of “Polynaphthalenes” Prepared by Two Mechanistically Distinct Routes

Cited by 52 publications

References 12 publications

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

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

Bergman Cyclization in Polymer Chemistry and Material Science

Unusual Cyclizations

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