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[Display omitted] • A novel coordination architecture, {[Co(toua)(4,4′-bpy)].2H 2 O} n (1), constructed using an unexplored polyether carboxylate linker (3,6,9-trioxaundecanedioic acid) and 4,4′-bipyridine. • 1 demonstrated dual sensing capabilities, employing both vapochromic and photoluminescence methods, for detecting ammonia and various amines. • 1 demonstrated the ability to selectively detect ammonia and amine vapors, with eye-detectable color changes and varying response times. • Notably, 1 exhibited a rare occurrence of both "turn-off" and "turn-on" sensing behaviors. This work presents the design, synthesis, and characterization of a new cobalt (II) based coordination architecture, {[Co(toua)(4,4′-bpy)].2H 2 O} n (1); where toua is 3,6,9-trioxaundecanaote and 4,4′-bpy is 4,4′-bipyridine tailored for efficient sensing of ammonia and amines. The formation and identity of 1 was confirmed by elemental analysis, spectroscopic study (FTIR and UV–visible spectroscopy), PXRD, XPS, FESEM, and BET analysis. The colorimetric sensing capability of 1 towards ammonia and various smaller-sized amines in the vapor phase through observable color changes is explored in this study. Their interaction with 1 is elucidated through FTIR, UV–Visible and Fluorescence spectroscopy, FESEM, and TCSPC analysis. The fluorescence sensing experiments demonstrate a remarkable quenching/enhancement effect with the addition of ammonia and various amines, showcasing the compound's sensitivity and selectivity. The quenching/enhancement efficiency follows the order: NH 3 >Ethylenediamine (EDA)>1,3-diaminopropane (DAP)>n-propylethylenediamine (n-PEDA), following the molecular dimensions and steric hindrance surrounding nitrogen atoms. Hydrogen bonds and host-guest interactions, including (C–H)pyridinium⋅⋅⋅N interactions, are identified as the driving forces for the sensing process. Additionally, the paper reveals a rare occurrence of both "turn-off" and "turn-on" sensing behavior for the same compound, showcasing its versatility. The calculated RSD for the fluorometric sensor was found to be 1.03 % calculated from its triplicate readings at 240 nm. Limits of detection (LODs) and Limit of Quantification (LOQs) for NH 3 (0.52 μM, and 1.74 μM) EDA (1.2 μM, and 4.2 μM), DAP (3.1 μM, and 10.5 μM), and n-PEDA (3.3 μM, and 11.2 μM) respectively) underscore the effective sensing capabilities of 1. The robustness of 1 upon exposure to amines was confirmed by PXRD. These findings justify that 1 is a promising vaporchromic probe for the fast and selective detection of ammonia and amines. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simplified approach for the fabrication of Co-CP nanoparticles has been reported. • Nanozyme-based colorimetric detection for Fe(II) ions is devised. • Sensing evidenced peroxide-reductase mimicking activity for Co-CP NPs. • The mechanism for the reported detection method is described using XPS and zeta analysis. • The practical utility is examined using real sample analysis. Nanozyme based sensors have evolved as an equable and productive approach for detecting obnoxious metal ions in water samples. A coherent and methodical outlook for nanozymatic sensors is provided in this work. A Co(II) based coordination polymer [Co(L) 1.5 (ac) 3 ] n named Co-CP, (L = N, N-(benzo-3,8-phenanthroline-2,7-diyl)diisonicotinamide and ac = CH 3 COO–) has been synthesized in this paper. Co(II) based coordination polymer nanoparticles (Co-CP NPs) constructed by using hand grinding process stimulates the nanozymatic action due to increased surface area and exposure of catalytically active sites. The fabricated Co-CP NPs were characterized using various sophisticated analytical techniques such as SCXRD, HRTEM, FESEM, PXRD etc. The NPs thus formed were about 27 nm in size and pertain porous sites. The Co-CP NPs exhibited peroxido-reductase mimicking activity for TMB(3,3′,5,5′-tetramethylbenzidine) oxidation. The catalytic action of the Co-CP NPs was utilized to detect Fe(II) ion selectively with a detection limit of 0.66 µM. The kinetics for the study were described using Michaelis-Menten curve. The K m and V max values for H 2 O 2 and Co-CP NPs were analyzed further to access the catalytic action of Co-CP NPs. XPS and zeta potential analysis were evidenced to elucidate the detection mechanism. The compatibility and practicality of the present method was also assured by actual water samples from different sources that showed good recovery percentage. Therefore, an economical, manageable and equable approach for using CPs as a sensing tool is provided hereby. [ABSTRACT FROM AUTHOR]