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The newly synthesized cyclotriphosphazene cored coumarin chemosensors 5, 6, and 7 were successfully characterized by 1 H NMR, 31 P NMR, and MALDI-TOF mass spectrometry. Additionally, the photophysical and metal sensing properties of the targeted compounds were determined by fluorescence spectroscopy in the presence of various metals (Li + , Na + , K + , Cs + , Mg 2+ , Ca 2+ , Ba 2+ , Cr 3+ , Mn 2+ , Fe 3+ , Co 2+ , Al 3+ , Hg + , Cu 2+ , Zn 2+ , Ag + , and Cd 2+ ) . The fluorescence titration results showed that compounds 5, 6, and 7 could be employed as fluorescent chemosensors for Fe 3+ ions with high sensitivity. The complex stoichiometry between final cyclotriphosphazene chemosensors and Fe 3+ ions was also determined by Job's plots., Competing Interests: CONFLICT OF INTEREST: none declared, (Copyright © 2020 The Author(s).)

Herein, a novel one step synthesis of multicomponent three dimensional polyacrylic acid (PAA) based conducting hydrogel (CH) incorporated with iron phthalocyanine functionalised graphene nanoplatelets (GPL-FePc) is reported. An amperometric glucose biosensor was fabricated by the immobilization of glucose oxidase (GOx) onto the synthesised PAA-VS-PANI/GPL-FePc-CH (where VS-PANI is vinyl substituted polyaniline). Scanning electron microscopy reveals the presence of three dimensional microporous structure with estimated pore size of 19 μm. The 5-(trifluoromethyl)-2-mercaptopyridine substitution onto FePc enabled the solubility of FePc in water and controls the aggregation of GPL-FePc in the synthesised CH. A sharp peak around 699 nm in UV-visible spectra confirms the presence of incorporated GPL-FePc into CH. Cyclic voltammogram of the synthesised CH biosensor exhibited well defined redox peaks with a ΔE p value of 0.26 V in Fe(CN) 6 3-/4- bench mark solution. The fabricated PAA-VS-PANI/GPL-FePc/GO x -CH amperometric biosensor resulted in remarkable detection sensitivity of 18.11 μA mM -1  cm -2 with an average response time of ∼1 s, linearity from 1 to 20 mM, and low detection limit of 6.4 μM for the determination of glucose., (Copyright © 2019 Elsevier B.V. All rights reserved.)