Nicotinonitrile centered luminescent polymeric materials: Structural, optical, electrochemical, and theoretical investigations

Abstract

Herein, we describe the design, synthesis, and structural characterization of three new push-pull type conjugative polymers, that is, VPPy 1-3 comprising strong electron-withdrawing N-heterocyclic nicotinonitrile scaffold coupled with electron-donating phenylene units through vinylene bridges, as promising candidates for optoelectronic applications. They were successfully synthesized from their respective co-monomers by simple polycondensation synthetic routes, viz. Knoevenagel and Wittig reactions. All the polymers were subjected to photophysical, electrochemical, thermal, and theoretical studies in order to ascertain their suitability in polymer light-emitting diode applications as blue emitters. Evidently, they are readily soluble in most of the organic solvents, enabling them easy solution-processable. These new polymers display strong blue photoluminescence at the peak in the range of 431 to 462 nm with a wide optical bandgap in the order of 2.55 to 2.63 eV. The obtained electrochemical data were employed to evaluate their HOMO/LUMOs. The density functional theory calculations generated useful information on their FMO, molecular geometries, and electronic properties. Also, the influence of their structural modification on the above-said properties was discussed in detail to reveal the structure-property relationship. Conclusively, these results illustrate the great prospective of this class of polymeric materials for the application in solutionprocessable blue LEDs.

The introduction of the disconnection approach into polymer synthesis

“…The strategies for analyzing the retrosynthesis of these double bonds usually include Aldol condensation, 28 Horner-Wadsworth-Emmons reaction, 29 Knoevenagel condensation, 30 and Wittig reaction. 31 These condensation reactions have already been successfully applied in constructing the polymer main chain (Figure 9). The mild reaction conditions, excellent chemical compatibility, and low price of these reactions are still shown in the synthesis of polymers.…”

Advances in the application of named reactions in polymer synthesis

“…Since the Horner-Wadsworth-Emmons reaction has apparent advantages over the traditional Wittig reaction, such as cheapness, mild conditions, and easy post-treatment, there have been continuously decreasing reports on the Wittig reaction in recent years.

Figure 11.Synthesis of three new push-pull type conjugative polymers. 56

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“…51 Likewise, it has been used for some time in polymer synthesis. [52][53][54][55] Airody Vasudeva Adhikari et al 56 recently described the design, synthesis, and structural characterization of three novel push-pull conjugated polymers, (Figure 11) namely VPPy1-3, composed of strongly electron-withdrawing N-heterocyclic nicotinonitrile scaffolds coupled via vinylidene bridges. Electron-donating phenylene units can be promising candidates for optoelectronic applications.…”

“…[76][77][78] Later, the palladium-catalyzed arylation or alkenylation of alkenes was called the Heck reaction. Since its discovery, the Heck reaction has become one of the most widely used tools for catalytic carbon-carbon bond formation in organic synthesis, 79 and it has been widely used in the 56 synthesis of small molecules. In recent years, its role in polymer synthesis should not be overlooked.…”

Recyclable photoluminescent composites via incorporating ZnS‐based phosphors into dynamic crosslinking elastomeric matrixes

“…Luminescent materials, under proper external stimuli, exhibit photoluminescent, electroluminescent, and mechano‐luminescent properties, [ 1–6 ] extensively applied in display, sensing, anticounterfeiting, bioimaging, and biological probes. [ 7–11 ] Three types of design strategies are generally employed to fabricate these materials, involving organic synthesis, [ 12 ] inorganic powder sintering, and polymer matrix/luminophore compositing.…”