The present study reports the application of three copper(II) coordination polymers, namely ¹_∞[Cu₃L₂(N₃)] CH₃COO (CP1), ¹_∞[Cu₃L₂(NO₃)]NO₃·2CH₃OH·2H₂O (CP2), and ¹_∞[Cu₃L₂(H₂O)](ClO₄)₂ (CP3), where H₂L stands for N,N′-bis[(2-hydroxybenzilideneamino)propyl]-piperazine) as catalysts for photocatalytic degradation of Acid Orange 7 and Methyl Orange dyes from single and binary aqueous solutions. The influence of the photocatalyst nature, hydrogen peroxide presence, reaction time, dye concentration, and catalyst dose on the photodegradation efficiency was studied. Under visible light irradiation, complex CP1 demonstrated the highest photodegradation efficiency of 92.40% and 80.50% towards Acid Orange 7 and Methyl Orange, respectively. The kinetic studies indicated that the photodegradation process followed a pseudo-first-order kinetics. The highest rate of the degradation process was obtained when CP1 is used, and the necessary time for the degradation of the dyes increases with increasing concentration of the dye solutions. The degradation efficiency of more than 75% after five recycling/reuse cycles of CP1 and the yields higher than 72% obtained for the degradation of dyes from the binary system demonstrate the photocatalytic capacity of CP1. A photocatalytic oxidation mechanism was proposed and the stability of the CP1 complex before and after the photodegradation process of dyes, both from simple and binary solutions, was investigated and confirmed.

The investigation primarily focuses on synthesizing Polyvinyl Chloride (PVC)-coordination polymer (CP) polymeric membranes that employ L-Cu-NO₃ (¹_∞[Cu₃L₂(NO₃)]NO₃·2MeOH·2H₂O based on the Schiff base H₂L, where H₂L stands for N,N’-bis[(2-hydroxybenzilideneamino)-propyl]-piperazine)) as a coordination polymer. The membrane’s capacity to hold moisture is greatly improved by the addition of CPs. The water contact angle dropped from 73.4° for the PVC to about 71° for the composite membrane, indicating that the CP–PVC polymer interactions improved the hydrophilicity. Impedance spectroscopy (EIS) was used to determine the membranes response to the tested concentrations of phenol solution at pH 9.11 in the concentration range of 10⁻¹⁰ to 10⁻² mol·L⁻¹. A PVC membrane with a 0.6 wt% L-Cu-NO₃ deposit on a Cu electrode yields the best response. Between 10⁻⁸ and 10⁻⁵ mol·L⁻¹ phenol, a linear dependence was found. The detection limit was 4.64 × 10⁻⁸ mol·L⁻¹.

The corrosion inhibitory performance of a coordination polymer, ¹_∞[Cu₃L¹₂(NO₃)](NO₃)·2H₂O and a complex compound, [Zn₂L²(CH₃COO)₂]·2H₂O, toward iron corrosion in a saline medium at pH 2.5 was investigated. Here, L¹ and L² stand for N,N’-bis[(2-hydroxybenzylideneamino)-propyl]-piperazine and N,N’-bis[(3-methoxysalicylideneamino)-propyl]-piperazine, respectively. This study was motivated by the recognized potential of organic compounds incorporating N, S, and O heteroatoms and π-conjugated electronic systems as effective corrosion inhibitors. The evaluation of the performance is determined using electrochemical impedance spectroscopy (EIS) and potentiometric methods (CP). The experimental findings reveal that an optimal inhibitor concentration of 100 ppm ensures enhanced corrosion protection. For both inhibitors, the corrosion rate decreased by two orders of magnitude compared with the untreated iron sample.

The title organic–inorganic hybrid salt, C₂H₇IN⁺·I⁻, is isotypic with its bromine analog, C₂H₇BrN⁺·Br⁻ [Semenikhin et al. (2024). Acta Cryst. E80, 738–741]. Its asymmetric unit consists of one 2-iodoethylammonium cation and one iodide anion. The NH₃ ⁺ group of the organic cation forms weak hydrogen bonds with four neighboring iodide anions, leading to the formation of supramolecular layers propagating parallel to the bc plane. Hirshfeld surface analysis reveals that the most important contribution to the crystal packing is from N—H...I interactions (63.8%). The crystal under investigation was twinned by a 180° rotation around [001].