Ultra-High Conductivity of Non-Conjugated Synthetic, Semisynthetic, and Zr(IV)-/ Zn(II)-/ Ni(II)-Coordinated Optoelectronic Polymers for High-Performance Voltammetric/ Impedimetric/ Luminometric Glucose Sensing

The exploration of purely aliphatic optoelectronic macromolecules with elevated conductivity, emission efficacy, redox capacity, and solubility in aqueous media should extend the application prospects of optoelectronic polymers. Here, initially, four purely aliphatic (synthetic) electroactive luminescent polymers (ELPs), followed by four semisynthetic electroactive luminescent inclusion polymers (ELIPs), and finally, three metal ion-inclusion polymer (semisynthetic) networks (M(II/IV)-MIPN, M = Ni(II)/ Zn(II)/ Zr(IV)) are strategically designed and synthesized. For the first time, alike aromatic/ conjugated polymers, aliphatic luminescent polymers imparting conductivities in the range of 355.6–137.7 mS cm^–1 are explored. Fourier transform infrared and nuclear magnetic resonance spectroscopies confirm the origination of cyclic aliphatic N-(5-methacryloyl-1,5-oxazocan-2-ylidene)-N-methylmethanaminium (MAOYMEMM) ion comprising an oxazocane ring during the synthesis of ELPs, ELIPs, Zr(IV)-MIPN, Ni(II)-MIPN, and Zn(II)-MIPN. In ELP3/ ELIP3 (optimum composition), Zr(IV)-MIPN, Ni(II)-MIPN, and Zn(II)-MIPN, spontaneous charge-/ electronic-transport from the electron rich oxyanion of −C(−O^–)═N⁺(CH₃)₃ in N,N-dimethylacrylamide to the electronically deficient carbonyl carbon in MAOYMEMM endows optical and electrical properties. In ELIP3/ Ni(II)-MIPN, β-cyclodextrin-/ Ni(II)-associated 333.71/ 242.44% enhancement in charge transfer efficacy is indicated from dual-state UV–vis and luminescence spectroscopies. Here, impedance measurements and cyclic voltammetric analyses of M(II/IV)-MIPN-modified glassy carbon electrodes (GCE) (GCE|Zn(II)-MIPN and GCE|Zr(IV)-MIPN) confirm the highest conductivity and oxidizing ability of Zn(II)-MIPN and Zr(IV)-MIPN, respectively. Finally, optoelectronic Zr(IV)-MIPN, Ni(II)-MIPN, and Zn(II)-MIPN showing the maximum open circuit potential (1.05 V vs Ag/AgCl), 242.44% enhancement of CT, and ultrahigh conductivity (355.6 mS cm^–1) are employed as efficient cyclic voltammetric (limit of detection (LOD) = 3.77 μM), luminometric (LOD = 3.64 nM), and impedimetric (LOD = 5.62 μM) glucose sensors, respectively. The significant efficiencies of multimethod sensing performed with Zr(IV)-MIPN, Ni(II)-MIPN, and Zn(II)-MIPN are indicated by high selectivity, sensitivity, stability, reproducibility, and appreciably low LODs.