4280-59-5Relevant academic research and scientific papers
Depolymerization of Hydroxylated Polymers via Light-Driven C-C Bond Cleavage
Nguyen, Suong T.,McLoughlin, Elizabeth A.,Cox, James H.,Fors, Brett P.,Knowles, Robert R.
supporting information, p. 12268 - 12277 (2021/08/23)
The accumulation of persistent plastic waste in the environment is widely recognized as an ecological crisis. New chemical technologies are necessary both to recycle existing plastic waste streams into high-value chemical feedstocks and to develop next-generation materials that are degradable by design. Here, we report a catalytic methodology for the depolymerization of a commercial phenoxy resin and high molecular weight hydroxylated polyolefin derivatives upon visible light irradiation near ambient temperature. Proton-coupled electron transfer (PCET) activation of hydroxyl groups periodically spaced along the polymer backbone furnishes reactive alkoxy radicals that promote chain fragmentation through C-C bond β-scission. The depolymerization produces well-defined and isolable product mixtures that are readily diversified to polycondensation monomers. In addition to controlling depolymerization, the hydroxyl group modulates the thermomechanical properties of these polyolefin derivatives, yielding materials with diverse properties. These results demonstrate a new approach to polymer recycling based on light-driven C-C bond cleavage that has the potential to establish new links within a circular polymer economy and influence the development of new degradable-by-design polyolefin materials.
Synthesis and Structures of [2.n]Metacyclophan-1-enes and their Conversion to Highly Strained [2.n]Metacyclophane-1-ynes
Akther, Thamina,Islam, Md. Monarul,Kowser, Zannatul,Matsumoto, Taisuke,Tanaka, Junji,Rahman, Shofiur,Alodhayb, Abdullah,Georghiou, Paris E.,Redshaw, Carl,Yamato, Takehiko
, p. 4167 - 4175 (2020/07/13)
The syntheses of syn-[2.n]metacyclophan-1-enes (n = 5, 6, 8) in good yields using the McMurry cyclization of 1,n-bis(3-formyl-4-methoxyphenyl)alkanes are reported. Conversion of syn-[2.6]- and [2.8]metacyclophan-1-enes to the corresponding highly strained syn-type [2.6]- and [2.8]metacyclophane-1-ynes was achieved by successive bromination and dehydrobromination reactions. An attempted trapping reaction of the putative corresponding [2.5]metacyclophane-1-yne by Diels–Alder reaction with 1,3-diphenylisobenzofuran failed due to its smaller ring size and strained structure. X-ray crystallographic analyses show that the triple bonds in syn-[2.6]- and [2.8]metacyclophane-1-ynes are distorted from linearity with bond angles of 156.7° and 161.4°, respectively. A DFT (Density Functional Theory) computational study was conducted to determine the stabilities of different conformations of the target compounds.
On the importance of the relative stereochemistry of substituents in the formation of nine-membered lactones by ring-closing metathesis
Cusson, Jean-Philippe,Chénard, Etienne,Hanessian, Stephen
, p. 1317 - 1324 (2015/08/05)
The effects of isopropyl substituents and molar concentration of diastereomeric esters toward the formation of nine-membered unsaturated lactones, in the context of the synthesis of the intermediates of the antihypertensive drug aliskiren, have been studied
En route to a molecular sheaf: Active metal template synthesis of a [3]rotaxane with two axles threaded through one ring
Cheng, Hei Man,Leigh, David A.,Maffei, Francesca,McGonigal, Paul R.,Slawin, Alexandra M. Z.,Wu, Jhenyi
supporting information; experimental part, p. 12298 - 12303 (2011/10/01)
We report that a 2,2′:6′,2″-terpyridylmacrocycle-Ni complex can efficiently mediate the threading of two alkyl chains with bulky end groups in an active metal template sp3-carbon-to-sp 3-carbon homocoupling reaction, resulting in a r
