Poly(arylene vinylene) Synthesis via a Precursor Step-Growth Polymerization Route Involving the Ramberg–Bäcklund Reaction as a Key Post-Chemical Modification Step

Abstract

The synthesis of conjugated copolymers based on poly(fluorene vinylene) [PFV] and poly(fluorene vinylene-co-carbazole vinylene) [PFVCV] was achieved via a previously unexplored precursor three-step synthetic route involving the Ramberg-Bäcklund reaction. The resulting conjugated (co)polymers proved highly soluble in common organic solvents, such as DCM, THF, or CHCl3. The solution step-growth polymerization between 2,7-bis(bromomethyl)-9,9'-dihexyl-9Hfluorene [F-Br] and 2,7-bis(mercaptomethyl)-9,9'-dihexyl-9H-fluorene [F-SH] was carried out under basic conditions at 100 °C in a mixture of MeOH and THF. The resulting polysulfides were then subjected to an oxidation reaction using m-CPBA, which was followed by the Ramberg-Bäcklund reaction in the presence of CF2Br2/Al2O3-KOH, thus achieving the desired PFV. Similarly, PFVCV could be synthesized through the same three-step sequence employing, in this case, 2,7bis(mercaptomethyl)-9-(tridecan-7-yl)-9H-carbazole (C-SH) and F-Br. Conjugated polymers with apparent molecular weights up to 15 kg.mol -1 and exhibiting promising optical features were obtained following this convenient synthetic strategy.

Synthesis of conjugated polymers via cyclopentannulation reaction: promising materials for iodine adsorption

“…The design of new conjugated polymers has become one of the chief topics of interest for scientific endeavors because of the importance of this latter class of materials in diverse applications, namely, light-emitting diodes (LEDs), [1][2][3] organic solar cells, [4][5][6][7] field-effect transistors (FETs), [8][9][10][11][12][13][14][15][16] sensors, 17 optical switches, [18][19][20][21][22] batteries, 23 and thermoelectrics. 24 In addition to the hitherto mentioned applications, conjugated microporous polymers (CMP) have become exceptionally eminent due to many reasons, notably their extended π-conjugation skeleton, high stability, synthesis versatility, large surface area, and excellent gas sorption properties.…”

Editing of Polymer Backbones

“…9 F. Deletion of SO2 from poly(arylmethylene sulfone) backbones via the Ramberg-Bäcklund reaction. 5 In a seminal study, Nozaki and coworkers coopted a classical organic transformation-the Baeyer-Villiger oxidation-to convert a polyketone to a poly(ketone-co-ester) (Figure 3C), effectively inserting oxygen atoms into the polymer backbone. Notably, the transformation proceeded regioselectively-the secondary alkyl group migrated exclusively-and the optical activity of the original polymer was preserved during the course of the transformation.…”

“…In 2018, Aravindu, Taton, Landais, and coworkers utilized the Ramberg-Bäcklund reaction to excise sulfur atoms in the form of SO2 from poly(arylmethylene sulfone) backbones to convert them to poly(arylene vinylene)s and unveil useful optical properties characteristic of such conjugated polymers (Figure 3F). 5 After purification, the edited polymers were isolated in low to moderate yields (43% and 53%) but, based on IR and NMR spectroscopy, the editing was essentially quantitative in these purified materials. Although other candidates for such processes exist in organic chemistry literature, undesired chain cleavage would inevitably accompany them.…”

“…8,170 The focus of Tantillo and Hoffmann's work was on hypothetical polymers they called "sigmatropic shiftamers," in which a structural defect (e.g., a s-bond "surrounded" by π-bonds) can propagate along the polymer through successive sigmatropic rearrangements. 171 There are four main types of shiftamer structures studied throughout their work: (1) ladderane shiftamers, 8 (2) s-polyacene, 172 (3) helicoid [1,7]-shiftamers, 170 and ( 4) tape [1,5]-shiftamers. 171,173 The latter two shiftamer types are technically not examples of backbone editing as we define it because the backbone graph remains unchanged; thus we will not discuss them further.…”

A Rapid Fluorescence Sensor for the Direct Quantification of Rongalite in Foodstuffs

“…Rongalite, also known as sodium formaldehyde sulfoxylate, is a versatile and commercially available reagent, which is typically used as an industrial bleaching agent for vat dyeing as well as a green reagent in organic synthesis [ 1 , 2 , 3 ]. Although rongalite possesses diverse applications, its addition to food as a decolourant is prohibited.…”