Well-defined polymers containing a single mid-chain viologen group: synthesis, environment-sensitive fluorescence, and redox activity

Wang, Zhaoxu; Tsarevsky, Nicolay V.

doi:10.1039/c6py00628k

Cited by 12 publications

(13 citation statements)

References 59 publications

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“…Aprotic polar solvents such as DMSO, DMF, and THF are known to stabilize cations and arene solvents, e.g., toluene or vinyl acetate can interact with the π-conjugated viologen scaffold. It was concluded that this effect could be exploited for the sensing of arenes of high interest, e.g., explosive compounds such as nitroarenes [43]. In addition to the highly challenging synthetic work presented in their work, Wang and Tsarevsky also reported on the solvatochromism of the obtained polymers and emphasized on the shifts of the fluorescence maxima of the polymers in solvents of different polarity (the corresponding phenomenon is often called fluorosolvatochromism [34]).…”

Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

“…The compounds are very interesting candidates for chromic applications; however, they exhibit low solubility in organic solvents, which limits their in-solution applications. On the other hand, Wang and Tsarevsky recently managed to synthesize and characterize another 4,4′-bipyridine-involving polymer [43]. Specifically, their poly(methyl methacrylate)-based polymers involves only one viologen unit in the middle of the polymeric chain ( Figure 8).…”

Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

“…In order to achieve that, they employed the synthetic route depicted in Figure 8. The key step of the synthesis On the other hand, Wang and Tsarevsky recently managed to synthesize and characterize another 4,4 -bipyridine-involving polymer [43]. Specifically, their poly(methyl methacrylate)-based polymers involves only one viologen unit in the middle of the polymeric chain ( Figure 8).…”

Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

“…The color of the emitted light observed was thus blue-green. The authors attributed the emission of higher energy (410 nm/3.02 eV) to the planarized conformer of the viologen, i.e., the conformer having coplanar both pyridine rings [43]. In turn, the secondary band of lower energy (540 nm or 2.30 eV) having lower emission intensity was attributed to a twisted viologen conformation.…”

Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

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Mono- and Di-Quaternized 4,4′-Bipyridine Derivatives as Key Building Blocks for Medium- and Environment-Responsive Compounds and Materials

Papadakis

2019

Molecules

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Mono-and di-quaternized 4,4 -bipyridine derivatives constitute a family of heterocyclic compounds, which in recent years have been employed in numerous applications. These applications correspond to various disciplines of research and technology. In their majority, two key features of these 4,4 -bipyridine-based derivatives are exploited: their redox activity and their electrochromic aptitude. Contemporary materials and compounds encompassing these skeletons as building blocks are often characterized as multifunctional, as their presence often gives rise to interesting phenomena, e.g., various types of chromism. This research trend is acknowledged, and, in this review article, recent examples of multifunctional chromic materials/compounds of this class are presented. Emphasis is placed on solvent-/medium-and environment-responsive 4,4 -bipyridine derivatives. Two important classes of 4,4 -bipyridine-based products with solvatochromic and/or environment-responsive character are reviewed: viologens (i.e., N,N -disubstituted derivatives) and monoquats (i.e., monosubstituted 4,4 -bipyridine derivatives). The multifunctional nature of these derivatives is analyzed and structure-property relations are discussed in connection to the role of these derivatives in various novel applications.Molecules 2020, 25, 1 2 of 30 recent) underlining the high versatility of this class of compounds [9,10,[12][13][14][15]. Perhaps, the most reviewed subject regarding the viologens is their electrochromism [13,14,16]. Viologens are known to undergo one-electron reductions electrochemically ( Figure 2) yielding colorful radicals i.e., cations that are stable in the absence of O 2 . Yet, their chromism can also be triggered through various stimuli (including light, heat, solvents, presence of various chemical species, pressure, etc.). All these possibilities shape the very versatile "chromic character" of viologens and generally of 4,4 -bipyridine derivatives. Even though this "chromic character" has only recently started gaining more attention and there is an increasing number of research articles emphasizing on the alternative uses of 4,4 -bipyridine derivatives, there are no reviews in this growing area up until now. Such an attempt is presented in this review paper with an emphasis on medium-and environment-responsive compounds and materials based on 4,4 -bipyridine. Primary focus is placed on viologen-involving solvatochromic systems as well as materials and compounds of this class whose chromic behavior is dependent on various environment stimuli. Molecules 2018, 23, x 2 of 30 Figure 2. Schemes depicting (a) the electrochromic cycle (1) and (b) the photochromic cycle of paraquat (A, counter anion). Structure and Properties of Viologens The Strong Electron-Withdrawing Character of ViologensThe strong electron-withdrawing character of viologens has been widely exploited in numerous molecular architectures and materials. Viologens can undergo reversible one-electron reductions forming radical cations (Figure 2a), which are vividly colo...

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Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

Section: Direct Medium-and Environment-responsive Viologensmentioning

confidence: 99%

See 3 more Smart Citations

Mono- and Di-Quaternized 4,4′-Bipyridine Derivatives as Key Building Blocks for Medium- and Environment-Responsive Compounds and Materials

Papadakis

2019

Molecules

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Well‐defined polymers containing high density of pendant viologen groups

Wang

Tsarevsky

2017

J. Polym. Sci. Part A: Polym. Chem.

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Atom transfer radical polymerization (ATRP) of a viologen-containing methacrylate, 1-propyl-1 0 -[2-(methacryloyloxy)ethyl]-4,4 0 -bipyridinium dihexafluorophosphate, is reported. To achieve good polymerization control, it was essential to use the viologen-based monomer with a hexafluorophosphate instead of halide counterion, and 2,2 0 -bipyridine as the ligand for the Cu-based ATRP catalyst. The solubility of produced cationic polymers could be tuned by anion metathesis: the polymers with hexafluorophosphate counterions were soluble in organic solvents (e.g., acetone, DMF), and those with chloride counterions were water-soluble. In aqueous solutions, the polymers (chloride salts) formed large aggregates, the sizes of which ranged from about 200 to about 400 nm (based on dynamic light scattering measurements) depending on the molecular weight. Upon addition of electrolytes (e.g., NaCl), the aggregates underwent dissociation. The apparent diffusion coefficients of the aggregates existing in aqueous solutions and the products of their electrolyte-induced dissociation were measured by diffusion-ordered NMR spectroscopy. The association-dissociation processes were also studied by fluorescence spectroscopy: the aqueous polymer solutions, which were originally fluorescent (k em 5 402 nm at k ex 5 350 nm), lost their fluorescence in the presence of NaCl. The addition of small amounts of the viologen-containing polyelectrolytes to solutions of inorganic salts (NaCl) altered the crystal morphology of the salts due to interaction of the multiple charged pendant groups with small ions. In the presence of reducing agents, the pendant viologen groups were converted to viologen radical-cations, which are prone to dimerize reversibly in aqueous solutions. Indeed, marked dimerization of viologen radical cations (with absorbance maxima at 520 and 870 nm) was observed in relatively dilute aqueous solutions (4 mg mL 21 ) upon addition of reducing agents (hydrazine).

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Acetocatechol functionalized viologen as polyfunctional material that responds to anion, cation and reductant in aqueous and organic solvents

Qiao

Bai

Zhao

et al. 2020

Arabian Journal of Chemistry

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Well-defined polymers containing a single mid-chain viologen group: synthesis, environment-sensitive fluorescence, and redox activity

Abstract: A difunctional viologen-based alkyl halide initiator was employed in the atom transfer radical polymerization of methyl methacrylate, which afforded well-defined polymers with a single mid-chain viologen functionality. The materials were fluorescent and also served as redox catalysts.

Cited by 12 publications

References 59 publications

Mono- and Di-Quaternized 4,4′-Bipyridine Derivatives as Key Building Blocks for Medium- and Environment-Responsive Compounds and Materials

Mono- and Di-Quaternized 4,4′-Bipyridine Derivatives as Key Building Blocks for Medium- and Environment-Responsive Compounds and Materials

Well‐defined polymers containing high density of pendant viologen groups

Acetocatechol functionalized viologen as polyfunctional material that responds to anion, cation and reductant in aqueous and organic solvents

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