Synthesis, Chiroptical, and Redox Properties of Ferrocene‐Containing Optically Active Polymers

ACS Appl. Polym. Mater.

Roy

Hassan

et al. 2023

The design and synthesis of pH-responsive nonconventional multi-light emitting macromolecules suitable toward high-performance pHsensitive reduction-associated chromo-fluorogenic sensing are very challenging and not reported to date. Herein, pH-and excitation-dependent redox active multi-light emitting macromolecular ratiometric sensors (MRSs) are synthesized through the polymerization of prop-2-enenitrile and N,Ndimethylamino acrolein in water medium. Of different MRSs, the optimum photophysical and reduction-associated chromo-fluorogenic sensing capabilities of MRS3 are explored through spectroscopic, thermal, photoluminescence, computational, microscopic, and electrochemical measurements alongside videographic representations of reduction associated rapid color changes from yellowish brown Fe(III) to pale green Fe(II), blue Cu(II) to green Cu(I) followed by brown Cu(0), and colorless Hg(II) to yellow Hg(I) at pH = 7.0, 8.0, and 9.0, respectively. The emissions of MRS3, MRS3canonical, and MRS3-aggregate at 434, 465, and 572 nm, respectively, are facilitated by the −C(�O)N(CH 3 ) 2 /−C(−O − )= N + (CH 3 ) 2 and −C�N heteroatomic luminophore-assisted inter-and intra-molecular nonconventional and conventional hydrogen bonds, n→π* transitions, dipolar interactions, N-branching associated rigidity, and hydrophobic interaction. The alteration of −C(�O)N(CH 3 ) 2 to −C(−O − )�N + (CH 3 ) 2 and significant decrease in bond order of −C�N are explored through spectroscopic, computational, and photophysical studies. MRS3, MRS3-canonical, and (MRS3-canonical)-aggregate are utilized toward reduction-associated chromo-fluorogenic sensing of Fe(III), Cu(II), and Hg(II) with very low limits of detection of 0.486, 0.276, and 0.016 ppb at pH = 7.0, 8.0, and 9.0, respectively.

Section: Resultsmentioning

confidence: 77%

Section: Chromo-fluorogenic Reduction-associated Selective Sensing Of...mentioning

confidence: 99%

Chromo-Fluorogenic Sensing of Fe(III), Cu(II), and Hg(II) Using a Redox-Mediated Macromolecular Ratiometric Sensor

ACS Appl. Polym. Mater.

Roy

Hassan

et al. 2023

“…The redox capability of NCFP was confirmed from cathodic potentials ( E pc ) at 0.20, −0.60, and −1.08 V alongside anodic potentials ( E pa ) at 0.15 and −0.23 V in cyclic voltammograms. , In NCFP aggregates, multiple potentials were ascribed to variable extent of conventional hydrogen bonding N–H···OC</N–H···O–H/N–H···O–C< and nonconventional C–H···O–C</C–H···OC/O–H···H–C< hydrogen bonding (intra- and inter-molecular) among NBP and HMP moieties alongside electronic interactions between n/π of HMP and π* of HMP + BHMP . In Cu(I)- NCFP , complexation through −C( O )N< and −C(O) O CH 2 – was confirmed via shifting of E pc from −1.08 and 0.15 to −0.95 and 0.16 V, respectively, disappearance of cathodic and anodic potentials of NCFP , and appearance of E pc at 0.15 V and E pa at −0.34 and 0.41 V (Figure g,h), confirming Cu(II)/Cu(I) redox couple formation.…”

Section: Resultsmentioning

confidence: 95%

“…hydrogen bonding (intra-and inter-molecular) among NBP and HMP moieties alongside electronic interactions between n/π of HMP and π* of HMP + BHMP. 54 In Cu(I)-NCFP, complexation through −C(O)N< and −C(O)OCH 2 − was confirmed via shifting of E pc from −1.08 and 0.15 to −0.95 and 0.16 V, respectively, 55 disappearance of cathodic and anodic potentials of NCFP, and appearance of E pc at 0.15 V and E pa at −0.34 and 0.41 V (Figure 7g,h), confirming Cu(II)/ Cu(I) redox couple formation. The redox couple was also supported by green color of Cu(I)-NCFP in visible light and FTIR, Cu 2p XPS, and computational studies.…”

Section: Resultsmentioning

confidence: 99%

Light-Emitting Redox Polymers for Sensing and Removal-Reduction of Cu(II): Roles of Hydrogen Bonding in Nonconventional Fluorescence

Roy

ACS Appl. Polym. Mater.

Sanfui

et al. 2022

Here, intrinsically luminescent multifunctional n-butyl prop-2-enoate-co-butyl 3-(N-(hydroxymethyl)prop-2-enamido)propanoate-co-N-(hydroxymethyl)prop-2-enamide (NBP-co-BHMPP-co-HMP) luminogens with 1:2, 1:4, 1:8, and 1:20 mole ratios of NBP/ HMP are synthesized via free radical polymerization, where the amidic BHMPP comonomer is anchored via N−C coupling of HMP and NBP. The optimum nonconventional fluorescent polymer (NCFP, NBP/HMP = 1:8) is suitable for sensitive detection, selective binding, and removal-reduction of Cu(II). The structures and light-emitting properties of NCFP, NCFP aggregates, Cu(II)-NCFP, and Cu(I)-NCFP; oxygen donor selective coordinations; and removal-reduction of paramagnetic Cu(II) are explored via spectroscopic, microscopic, density functional theory-reduced density gradient, rapid color change under visible light, chromaticity-1931 plots, and electrochemical measurements. The striking aggregationenhanced green fluorescence is associated with extensive nonconventional and conventional hydrogen bondings in NCFP aggregates and through space electronic interactions involving NBP, HMP, and BHMPP moieties. Here, the Cu(II)/Cu(I) redox couple is confirmed via shifting of E pc from −1.08/+0.15 to +0.95/+0.16 V; E pc and E pa at +0.15 and −0.34/+0.41 V, respectively; green color of Cu(I)-NCFP under visible light; Fourier transform infrared and Cu 2p X-ray photoelectron spectroscopies; and computational studies. The limit of detection, Stern−Volmer constant, redox potentials, and adsorption capacity of NCFP are 3.61 nM/0.229 ppb, 4.27 × 10 3 [M] −1 , and +0.15/+0.41/−0.34 V, and 49.41 mg g −1 , respectively.

“…[73][74][75][76][77][78] In ALP3-aggregate, multiple E pa and E pc were attributed to variable functional groups alongside the various extent of intermolecular hydrogen bonding. [79,80] The variable ALP3-aggregates were explored earlier in AEE studies, FE-SEM images and DLS studies (Figures S3, Supporting Information, 3e, and 7b,c). The redox activity of ALP3-aggregate and conversion of Cu(II)→Cu(I) were supported from CV studies.…”

Section: Redox Activity Of Alp3 and Reduction Of Cu(ii) To Cu(i)mentioning

confidence: 99%

Nontraditional Redox Active Aliphatic Luminescent Polymer for Ratiometric pH Sensing and Sensing‐Removal‐Reduction of Cu(II): Strategic Optimization of Composition

Macromol. Rapid Commun.

Hassan

Chowdhury

et al. 2022

Here, redox active aliphatic luminescent polymers (ALPs) are synthesized via polymerization of N,N‐dimethyl‐2‐propenamide (DMPA) and 2‐methyl‐2‐propenoic acid (MPA). The structures and properties of the optimum ALP3, ALP3‐aggregate and Cu(I)‐ALP3, ratiometric pH sensing, redox activity, aggregation enhanced emission (AEE), Stokes shift, and oxygen‐donor selective coordination‐reduction of Cu(II) to Cu(I) are explored via spectroscopic, microscopic, density functional theory‐reduced density gradient (DFT‐RDG), fluorescence quenching, adsorption isotherm‐thermodynamics, and electrochemical methods. The intense blue and green fluorescence of ALP3 emerges at pH = 7.0 and 9.0, respectively, due to alteration of fluorophores from –C(═O)N(CH3)2/ –C(═O)OH to –C(O−)═N+(CH3)2/ –C(═O)O−, inferred from binding energies at 401.32 eV (–C(O−)═N+(CH3)2) and 533.08 eV (–C(═O)O–), significant red shifting in absorption and emission spectra, and peak at 2154 cm−1. The n−π* communications in ALP3‐aggregate, hydrogen bondings within 2.34–2.93 Å (intramolecular) in ALP3 and within 1.66–2.89 Å (intermolecular) in ALP3‐aggregate, respectively, contribute significantly in fluorescence, confirmed from NMR titration, ratiometric pH sensing, AEE, excitation dependent emission, and Stokes shift and DFT‐RDG analyses. For ALP3, Stokes shift, excellent limit of detection, adsorption capacity, and redox potentials are 13561 cm−1/1.68 eV, 0.137 ppb, 122.93 mg g−1, and 0.33/−1.04 V at pH 7.0, respectively.