Exploring Through-Space Charge Transfer-Mediated Optoelectrochemical\nProperties of Dual-State Luminescent Aliphatic Polymers and Optoelectronic\nResponses toward Metal Ions

Herein, natural-synthetic hybrid\ndual-state luminescent conducting\npolymers (DLCPs/DLCP1–DLCP8) possessing significant optoelectrochemical\nproperties are strategically developed by the polymerization of prop-2-enamide,\ncis-butenedioic acid, 2-acrylamido-2-methylpropane-1-sulfonic acid,\nand in situ-generated 2-(3-acrylamidopropanamido)-2-methylpropane-1-sulfonic\nacid alongside the grafting of gum tragacanth. The spectroscopic data\nof aliphatic DLCPs affirm DLCP7 as the most stable supramolecular\nassembly endowing optoelectronic properties. Computational calculations\nidentified −C(O)NH–, −C(O)OH,\n−OH, and −SO<sub>3</sub>H as subluminophores. The absorption\nspectra, excitation wavelength-/solvent-polarity-/concentration-dependent\nluminescence, solid state luminescence, aggregation-induced enhanced\nluminescence, and time-correlated single photon count (TCSPC) studies\nconfirm the occurrence of aggregation-mediated intramolecular through-space\ncharge transfer (ITSCT) in the excited state of DLCP7. Mulliken charge,\nnatural bond orbital, dipole moments, and electronic potential surface\nanalyses confirm the charge donor–acceptor system in DLCP7.\nFurthermore, the selective optoelectronic response of DLCP7 toward\nCa<sup>2+</sup>/Cu(II) at 438/574 nm is explored using ultraviolet–visible\nspectra, TCSPC analyses, a dynamic light scattering study, and computational\ninvestigations. The chelation-enhanced luminescence and ITSCT inhibition\nare responsible for turn-on and turn-off detections of Ca<sup>2+</sup> and Cu(II), respectively. Cu(II) → Cu(I) reduction in a DLCP7\nsolution is inferred from electrochemical and spectroscopic analyses.\nThe conductivities of 9.65 × 10<sup>–5</sup> S cm<sup>–1</sup> (solid state) and 44.35 × 10<sup>–5</sup> S cm<sup>–1</sup> (solution) in DLCP7 are validated by current–voltage\nand electrochemical impedance measurements. Again, strong electronic\nconductivities of 43.89 × 10<sup>–5</sup> S cm<sup>–1</sup> (solid state)/53.34 × 10<sup>–5</sup> S cm<sup>–1</sup> (solution) and 45.42 × 10<sup>–5</sup> S cm<sup>–1</sup> (solid state)/64.81 × 10<sup>–5</sup> S cm<sup>–1</sup> (solution) are observed in Ca<sup>2+</sup>-DLCP7 and Cu(II)-DLCP7,\nrespectively.