This work reports, for the first time, the application of a copper(I) complex, namely [Cu(SCN)(PPh3)(dpa)] (SCN = thiocyanate, PPh3 = triphenylphosphine, dpa = 2,2 '-dipyridylamine), in the construction of a modified electrochemical screen printed carbon electrode.This sensor represents the first electrochemical device utilizing this copper(I) complex for the simultaneous detection of hydroquinone (HQ) and resorcinol (RS) in natural water. The influence of the solvent used to disperse the Cu(I) complex was investigated, and the results showed that the use of acetonitrile (MeCN) favored the development of a more efficient sensor with a larger active surface area (0.120 cm2), compared to the case when dimethylformamide (DMF) was employed, as was also confirmed by the different coverages of the sensors surface through scanning electron microscopy (SEM) analysis. The newly developed modified sensor demonstrated significant electrocatalytic activity, thus confirming its usefulness for the detection of phenolic compounds. Selectivity studies performed in the presence of structurally related phenolic interferents revealed only minor effects on the electrochemical response, confirming the robustness of the sensor. Using differential pulse voltammetry (DPV), the [Cu(SCN)(PPh3)(dpa)]/MeCN/C-SPE sensor exhibited excellent performance over a linear range of 0 mu M to 0.045 mu M, with limits of detection (LOD) of 16.81 nM for HQ and 2.01 nM for RS, and limits of quantification (LOQ) of 56.04 nM and 4.03 nM, respectively. The sensor also showed high reproducibility and accuracy in real water samples, with recoveries ranging from 88.45% to 114.12%, validating its potential for practical applications in environmental monitoring.

Two new mononuclear tetrahedral copper(I) thiocyanate complexes, [Cu(NCS)(PPh3)(bq)] (1) and [Cu(NCS)(PPh2py)(bq)] (2) (PPh3 = triphenylphosphine, PPh2py = diphenyl(2-pyridyl)phosphine, bq = 2,2'-biquinoline), were synthesized and structurally characterized in order to investigate the effect of subtle ligand modification on redox behaviour and interfacial electron transfer. Replacement of the triphenylphosphine ligand with the mixed phosphine-pyridine donor PPh2py introduces a distinct electronic perturbation at the Cu(I) center, while preserving the overall coordination geometry. Single-crystal X-ray diffraction analysis revealed that both Cu(I) complexes crystallize in the triclinic P1̄ space group and adopt four-coordinate geometries with N3P donor sets composed of bidentate biquinoline, monodentate phosphine ligands and terminal N-coordinated thiocyanate anions. The calculated τ4 values of 0.89 for 1 and 0.85 for 2 indicated slightly distorted tetrahedral coordination environments around the Cu(I) centres. Electrochemical impedance spectroscopy confirmed the improved interfacial electron transfer after immobilization of the complexes on glassy carbon electrodes (GCE), as the charge-transfer resistance (Rct) decreased from 14 754 Ω for the bare GCE to 4773.8 Ω for GCE modified with complex 1 (GCE-1) and 6141.8 Ω for GCE modified with complex 2 (GCE-2), indicating that ligand substitution strongly influences electron transfer at the electrode interface. Cyclic voltammetry (CV) studies in the ferri/ferrocyanide redox probe revealed distinct interfacial behaviours, with GCE-1 showing a predominantly diffusion-controlled response and an increased electroactive surface area of 0.0349 cm2, compared with 0.0149 cm2 for the bare GCE, whereas GCE-2 exhibited adsorption-controlled behaviour with an estimated electroactive surface coverage of 2.35 × 10-9 mol cm-2. The combined structural and electrochemical data establish a direct correlation between ligand design and electrochemical response, showing that even minimal modifications at the molecular level can significantly impact macroscopic electron transfer processes. These findings provide new insight into the role of ligand environment in tuning the redox behaviour of Cu(I) systems and contribute to the rational design of functional coordination compounds for electrochemical applications.

Surface modification of zinc oxide nanoparticles (ZnO NPs) with organosilane capping agents represents an effective strategy to control their physicochemical and biological properties. In this work, we report for the first time the use of halogenosilanes, namely (3-chloropropyl)trimethoxysilane (CPTMS), (3-bromopropyl)trimethoxysilane (BPTMS) and (3-iodopropyl)trimethoxysilane (IPTMS), for the surface functionalization of ZnO NPs obtained by chemical precipitation. Structural and morphological characterization (PXRD, TEM, SEM-EDX and FTIR) confirmed successful surface modification and revealed a significant particle size reduction from ~31 nm for unmodified ZnO to ~8 nm for BPTMS-modified ZnO (ZnO_b). The biological evaluation showed that halogenosilane-modified ZnO NPs exhibit enhanced cytotoxic activity against prostate cancer cell lines (PC3 and 22Rv1), with ZnO_b displaying the highest activity, likely associated with improved cellular uptake and increased reactive oxygen species (ROS) generation. In contrast, antimicrobial assays revealed only moderate bactericidal effects against Escherichia coli and Staphylococcus aureus at relatively high concentrations (≥1250 µg mL-1), while no significant activity was observed against Pseudomonas aeruginosa, Burkholderia contaminans or Candida spp., within the tested range. These findings suggest that halogenosilane functionalization modulates the biological profile of ZnO nanoparticles by enhancing anticancer effects while also influencing microbiocidal activity, highlighting the role of surface chemistry in tuning biological selectivity. The present study supports the concept that rational surface engineering of ZnO-based nanoplatforms can be exploited to favor tumor-targeted activity over broad-spectrum antimicrobial effects, providing new perspectives for the design of application-oriented nanomaterials.

The reaction of copper(I) thiocyanate (CuSCN) with triphenylphosphine (PPh3) and 2,2’-dipyridylamine (dpa) in acetonitrile, at room temperature for just two hours, led to the formation of the photoluminescent complex [Cu(SCN)(PPh3)(dpa)], which exhibits intense blue-green photoluminescence in the solid state. This synthesis route represents an advancement over previously reported method that required longer reaction time and different solvent, thus offering a more efficient and practical approach. Single-crystal X-ray diffraction revealed a novel crystal structure featuring a slightly distorted tetrahedral geometry around the Cu(I) center, stabilized by P, N, and S donor atoms from the ligands and thiocyanate. The resulting Cu(I) complex was applied to fluorescent detection studies and showed a strong affinity for the pharmaceutical analytes sodium diclofenac and tetracycline hydrochloride. This interaction was evidenced by significant fluorescence quenching, low limits of detection (LOD) of 3.14 µM for sodium diclofenac and 0.33 µM for tetracycline hydrochloride, and high binding constants (Kb) of 0.00714 µM−1 and 0.00425 µM−1, respectively. The complex exhibited a linear fluorescence response within relevant concentration ranges, suggesting excellent sensitivity and potential applicability for detecting trace pharmaceutical residues. These findings highlight the promise of this complex as a practical and efficient sensor, with implications for environmental monitoring and pharmaceutical quality control.

A series of previously reported mononuclear zinc(II) complexes, [Zn(t py)Br-2] (1), [Zn(bq)Br-2] (2), [Zn(bpy)Br-2] (3), [Zn(dpa)Br-2] (4) (tpy = 2,2':6',2"-terpyridine, bq = 2,2'-biquinoline, bpy = 2,2'-bipyridyl, dpa = 2,2'-dipyridylamine), was synthesized via a simplified one-step ethanol-based procedure and investigated for their photoluminescent properties and sensing performance toward sodium diclofenac. Fluorescence spectroscopy revealed that complexes 1 , 3 and 4 display prominent emission bands in the UV region upon excitation at 260 nm, attributed to ligand-centered pi-pi* transitions. These complexes demonstrated significant and selective fluorescence quenching in the presence of sodium diclofenac, with low limits of detection (LOD as low as 4.98 & times;10(-3) mu M) and quantification (LOQ down to 1.66 & times;10(-2 )mu M). Binding studies confirmed a 1:1 stoichiometry and yielded association constants in the range of 0.0117 -0.0146 mu M-1. Stern-Volmer analyses indicated a predominantly static quenching mechanism via supramolecular complex formation. These findings highlight the potential of structurally simple Zn(II) complexes, synthesized through a facile protocol, as efficient fluorescent sensors for pharmaceutical contaminants such as diclofenac, with relevance to environmental and analytical applications.

In the present work, the adsorption efficiency of chitosan flakes towards ferric ions from aqueous medium by varying several experimental factors, such as pH, adsorbent dosage, contact time and ferric ions concentration, was investigated. The obtained results have shown that the amount of adsorbed Fe(III) ions increases with the contact time, reaching the equilibrium within 5 h, at ambient temperature. The optimal pH to ensure the adsorption of Fe(III) ions was established at 3.0 - 3.2 for the solutions containing 100 mg/L and 200 mg/L Fe(III) ions. The adsorption of Fe(III) ions on chitosan flakes was established at more than 80% (mg Fe/g adsorbent). The adsorption isotherm gained through two equilibrium models, the Freundlich and Langmuir isotherms, were analysed and the equilibrium isotherm was better matched with the Langmuir model. The Fe(III) ions are adsorbed by chitosan through the amine and hydroxyl groups, chitosan being an effective adsorbent material for the retention of metal ions, with possible application in environment and medicine. Scanning electron microscopy (SEM) was also employed to confirm the eventual structural changes of the chitosan matrix upon the adsorption of Fe(III) ions.

Surface modification of inorganic nanomaterials through functionalization with organic capping agents may be regarded as a very useful and hand-on strategy to avoid particle agglomeration, thus improving the current properties and even to design new ones. In this context, we here report a simple, low-cost and high-yielding method for the fabrication of semiconductor zinc sulphide nanoparticles (ZnS NPs) by chemical co-precipitation, using the new capping agents tris(hydroxymethyl)aminomethane (TRIS) and 4-(2-hydroxyphenyl)-2-(morpholin-4-yl)-1,3-thiazole (DF). Powder X-ray diffraction (PXRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy allowed to confirm the important effect of the adopted capping agents in the preparation of ZnS NPs with size reduction from ca. 40 nm in unmodified ZnS NPs to ca. 10 nm in ZnS NPs modified with either TRIS or DF capping agents. Such an effect comes along with enhanced photoluminescence of the organo-modified ZnS NPs, with the maximum emission centred at 560 nm, and an increase of the band gap energy from 3.71 eV in unmodified ZnS NPs to 3.83 eV in organo-modified ZnS NPs.

The tetratopic ligand 1-H-pyrazol-3,4,5-tricarboxylic acid (H(4)PZTC) has been used for the first time to prepare the new metal azolate/carboxylate (MAC) frameworks [Co-3(HPZTC)(2)(H2O)(6)]& middot;2H(2)O (MAC-1), [Co(H(2)PZTC)(DMF)(H2O)](2) (MAC-2) and [Cd-2(PZTC)(H2O)(2)] (MAC-3), along either conventional or solvothermal routes. As assessed by thermogravimetric analysis, before decomposition the three MAC frameworks undergo partial decarboxylation over 200 degrees C. Powder X-ray diffraction unveiled 1-D chains alternating monomeric and dimeric units in MAC-1, 1-D hydrogen bonded strands of dimeric units in MAC-2 and a 3-D non-porous network in MAC-3.

Abstract Various studies have shown that ultrafiltration membranes are successfully involved in the removal process of most organic pollutants from wastewater. In this context, the hydrodynamic characteristics of a modified cellulose ultrafiltration membrane were evaluated. This composite membrane type has been proposed for the separation of colloidal matter from industrial wastewater in Galati City area (Romania). Another purpose of this paper was also to determine the volume flows, along with the permeate and concentrate fluxes through the technical membrane taken under study. Furthermore, a comparative analysis of three samples of industrial water from Galați City area in terms of the degree of contamination was performed. Surface modification was evaluated using scanning electron microscopy. Results indicated that the industrial wastewater from the steel factory Liberty Galati was significantly more impure than the water from Cătuşa Lake, which in turn was more impure than the water from Siret River, as indicated by comparative analysis of the water samples subjected to the ultrafiltration operation through semipermeable technical membranes. It was shown that the decrease of the permeate flux at the modified cellulosic membrane was accentuated in the first moments, probably due to the clogging of the surface pores that present an uneven distribution. The results of the present study show that the cellulosic membrane used has pore diameters which correspond to the values recommended for the retention of colloidal matter.

Zinc oxide (ZnO) is a largely investigated semiconducting nanomaterial for photocatalytic applications and is an excellent active layer candidate in photovoltaics. Among native defects, having a primary role in ZnO optoelectronic properties, the influence of nearly ubiquitous planar faults of wurtzite sequences in ultrasmall (<= 5 nm) nanocrystals (NCs) remains poorly understood. Here, we present a thorough study of ZnO NCs prepared under morphological control of covalently grafted vinyltrimethoxysilane (VTMS) and exhibiting either narrowing or widening of the band gap upon NCs downsizing, depending on the NC growth rate. By using synchrotron X-ray total scattering data, atomistic models and the Debye Scattering Equation (DSE) method, complemented by spectroscopic (FTIR and UV-vis) investigations, we provide a comprehensive quantitative picture in which effects from planar defects are disentangled from those due to NC size, morphology, and lattice strain (here controlled by preferential binding of VTMS on the ZnO basal faces). When faults occur in high concentration (linear density up to 1.6 x 10 6 cm(-1)), NCs exhibit optical band gap narrowing (3.27 eV vs 3.37 eV in bulk ZnO), whereas gap widening (3.52 eV) is observed at a lower density (0.8 x 10(6) cm(-1)), at which quantum-size confinement effects prevail. Supported by photoluminescence and photodegradation experiments, surface defect passivation by VTMS, affecting visible emissions and photocatalytic properties of ZnO, is also discussed in relation to silane coating and fault-driven bandgap. This work sheds light on the complex interplay among planar defects, quantum size effect, and surface modifications in ultrasmall ZnO NCs and on the importance of advanced X-ray total scattering methods toward atomically precise control of defects in nanostructures.

Root extracts from Danube Delta Nymphaea alba were used to prepare gold nanoparticles (AuNPRn) by reducing HAuCl4 at different pHs (6.4–8.4) using ultrasonic irradiation: an easy, cheap, eco-friendly and green approach. Their antibacterial and anticancer activities were evaluated against Staphylococcus aureus and Escherichia coli, and A2780 ovarian cancer cells, respectively. The AuNPRn were characterized concerning their phytoconstituents (polyphenols, flavonoids and condensed tannins) and gold content. All of the nanoparticles were negatively charged. AuNPRn exhibited a hydrodynamic size distribution ranging from 32 nm to 280 nm, with the larger nanoparticles being obtained with an Au/root extract ratio of 0.56, pH 7 and 10 min of sonication (AuNPR1), whereas the smallest were obtained with an Au/root extract ratio of 0.24, pH 7.8 and 40 min of sonication (AuNPR4). The TEM/SEM images showed that the AuNPRn had different shapes. The ATR-FTIR indicated that AuNPRn interact mainly with hydroxyl groups present in the polyphenol compounds, which also confirm their high antioxidant capacity, except for AuNPR2 obtained at pH 6.4. Among the AuNPRn, the smallest ones exhibited enhanced antimicrobial and anticancer activities.

Abstract Introduction Nanoparticles (NPs) are a wide class of materials that include particulate substances sized less than 100 nm. Inorganic ZnO NPs have found applications in several industrial fields such as the optical, electronic, pharmaceutical and cosmetics [1]. However, in many specific fields the applications are limited, since the particles tend to aggregate/agglomerate due to the hydrophilic nature of the surface. For potential clinical applications, surface modification of ZnO plays a crucial role in the biocompatibility of ZnO NPs [2]. Using organosilane modifying agents, improved hydrophobicity of the resulting ZnO NPs, induced by the non-polar terminal groups, can be achieved, and thus, very small and highly dispersed particles can be obtained. ZnO silanes were found to have antibacterial activity against several pathogens [3]. The NP size highly influenced the antibacterial activity, which increase with decreasing size. The ZnO NPs may induce bacterial cell membrane damage, resulting in bacterial cell death. Motivated by these findings and others reporting anticancer activity for pristine ZnO NPs [4], the aim of this study was to investigate the anticancer activity and mechanism of cell death of silane-modified ZnO nanoparticles against A2780 ovarian cancer cells and evaluate if for the cancer cells a correlation between size and activity was also observed. Materials and Mmethods The silane modified ZnO NPs were prepared by the addition of (3-glycidyloxypropyl) trimethoxysilane (GPTMS) as a surface modifier at 0% (G0) and 10% (G3) molar ratio of Si/Zn. The obtained NPs were characterised by high resolution transmission electron microscopy (HRTEM), X-ray diffraction and UV-Vis spectrometry. The cytotoxic activity in ovarian cancer cells were assessed by the MTT colorimetric assay. The morphological cellular alterations were visualised by electron microscopy (TEM). Results The silane modified ZnO NPs exhibited significant cytotoxic activity against A2780 ovarian cancer cells. The NP size, ca. 13 nm for G0 and ca. 3 nm for G3, highly influenced the cytotoxic activity, which increased with decreasing particle size, IC50: ∼100 µg/mL(G0) and ∼30 µg/mL(G3). The ZnO silanes affected the cellular integrity by the induction of organelle damage evidenced by TEM. Discussion and conclusions Although preliminary, results indicate that ZnO silanes are interesting platforms to explore as anticancer agents. Studies on the ultrastructural level (TEM/SEM) are needed to understand their cytotoxic mechanism and to give clues on their potential targets.

Surface modification of zinc oxide nanoparticles (ZnO NPs) is a strategy to tune their biocompatibility. Herein we report on the synthesis of a series of fluorescent ZnO NPs modified with 2–10% (3-glycidyloxypropyl)trimethoxysilane (GPTMS) to investigate the fluorescence properties and to explore their applications in microbiology and biomedicine. The obtained ZnO NPs were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). Size reduction occurred from ca. 13 nm in unmodified ZnO to 3–4 nm in silane-modified samples and fluorescence spectra showed size-dependent variation of the photoemission bands' intensity. The antibacterial and cytotoxic activities were investigated on Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, and in ovarian (A2780) and prostate (PC3) cancer cells by tetrazolium/formazan-based methods. The antibacterial effect was higher for E. coli than S. aureus, while the cytotoxic activity was similar for both cancer cells and varied with the particle size. Cell death by apoptosis, and/or necrosis versus autophagy, were explored by flow cytometry using an Annexin V based-method and transmission electron microscopy (TEM). The main mechanism of ZnO NPs toxicity may involve the generation of reactive oxygen species (ROS) and the induction of apoptosis or autophagy. This work revealed the potential utility of GPTMS-modified ZnO NPs in the treatment of bacterial infection and cancer.

Seeking to enrich the yet less explored field of scorpionate complexes bearing antioxidant properties, we, here, report on the synthesis, characterization and assessment of the antioxidant activity of new complexes derived from three scorpionate ligands. The interaction between the scorpionate ligands thallium(I) hydrotris(5-methyl-indazolyl)borate (TlTp4Bo,5Me), thallium(I) hydrotris(4,5-dihydro-2H-benzo[g]indazolyl)borate (TlTpa) and potassium hydrotris(3-tert-butyl- pyrazolyl)borate (KTptBu), and metal(II) chlorides, in dichloromethane at room temperature, produced a new family of complexes having the stoichiometric formula [M(Tp4Bo,5Me)2] (M = Cu, 1; Zn, 4; Cd, 7), [M(Tpa)2] (M = Cu, 2; Zn, 5; Cd, 8), [Cu(HpztBu)3Cl2] (3), [Zn(TptBu)Cl] (6) and [Cd(BptBu)(HpztBu)Cl] (9). The obtained metal complexes were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and elemental analysis, highlighting the total and partial hydrolysis of the scorpionate ligand TptBu during the synthesis of the Cu(II) complex 3 and the Cd(II) complex 9, respectively. An assessment of the antioxidant activity of the obtained metal complexes was performed through both enzymatic and non-enzymatic assays against 1,1-diphenyl-2-picryl- hydrazyl (DPPH·), 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+·), hydroxyl (HO·), nitric oxide (NO·), superoxide (O2−) and peroxide (OOH·) radicals. In particular, the complex [Cu(Tpa)2]⋅0.5H2O (2) exhibited significant antioxidant activity, as good and specific activity against superoxide (O2−·), (IC50 values equal to 5.6 ± 0.2 μM) and might be identified as auspicious SOD-mimics (SOD = superoxide dismutase).

The new coordination polymers (CPs) [Zn(tr2ad)Cl2]n, {[Cu(tr2ad)Cl]Cl∙4H2O}n, [Cd2(tr2ad)Cl4]n, {[Cu(tr2ad)(NO3)](NO3)}n and {[Cd(tr2ad)(NO3)](NO3)∙H2O}n were obtained in the form of air- and moisture-stable microcrystalline powders by the solvothermal reactions of zinc(II), copper(II) and cadmium(II) chlorides or nitrates with the ligand 1,3-bis(1,2,4-triazol-4-yl)adamantane (tr2ad). Investigation of the thermal behaviour assessed the thermal stability of these CPs, with [Cd2(tr2ad)Cl4]n starting to decompose only around 365 °C. As retrieved by powder X-ray diffraction, while [Zn(tr2ad)Cl2]n features 1-D chains along which the metal centre shows a tetrahedral geometry and the spacer is exo-bidentate, the other CPs contain 2-D double-layers in which the metal ions possess an octahedral stereochemistry and the linker is exo-tetradentate. A comparative structural analysis involving known coordination compounds containing the tr2ad ligand enabled us to disclose (i) the versatility of the ligand, as far as the coordination modes are concerned; (ii) the variability in crystal structure dimensionality, ranging from 1-D to 3-D; (iii) the fact that, to the best of our knowledge, [Zn(tr2ad)Cl2]n is the first ZnII-based CP containing the tr2ad spacer.

A new mixed lanthanide(III) complex [LaNd(mu(2)-DPY)(mu(4)-SO4) 2 (Et3N)]Br-2 center dot 2H(2)OMeOH (La-Nd-DPY) was obtained by the reaction of N,N'-diphenacyl-4,4'-dipyridinium dibromide (DPB) with a mixture of La(III) and Nd (III) sulfates in a 2:1 M ratio, in the presence of triethylamine (Et3N). The method used for the synthesis of LaNd-DPY promoted the in situ transformation of the pro-ligand DPB into the dipyridinium ylide-based ligand. Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), thermogravimetric analysis (TGA) and mass spectrometry (MS) concurred to propose a linear polymeric structure for La-Nd-DPY, in which both La(III) and Nd(III) ions are six-coordinated. Cyclic voltammetry was also used to assess the redox potential of the mixed complex. Scanning electron microscopy (SEM) showed quite uniform and homogeneous fibrillary net-like morphology and also confirmed, by means of EDX analysis, the presence of both lanthanide (III) ions in the mixed complex. UV-vis absorption spectroscopy demonstrated that the mixed Ln complex is stable up to 1 h in DMSO and up to 72 h under the physiological conditions used for cell culture. The cytotoxic activity of La-NdDPY in cancer cell lines of ovarian (A2780), breast (MCF7) and prostate (PC3) origins and in multicellular tumor spheroids derived from PC3 cells was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and acid phosphatase (APH) assays. Compared to cisplatin this new complex showed improved toxicity, with IC50 values at least 10 times higher, even at 24 h of exposure. The cytotoxic effects seemed to be mediated by reactive oxygen species (ROS) generation but not apoptosis, confirmed by a caspase-3/7 activation and Hoechst nuclei staining assays. The mechanism of cell death observed on the cytotoxicity assays is probably due to other pathways of cell death, which deserve to be further investigated.

A family of fifteen quaternary ammonium salts (QAs), bearing the 1,2-bis(4-pyridyl)ethane core, were obtained using for the first time two different green methods, such as microwave (MW) and ultrasounds (US) irradiation, with very good yields and in much shorter times compared to the classical method, and an assay on their antimicrobial action against Escherichia coli (E. coli) was carried out. While 12 to 24 h were required for complete alkylation of 1,2-bis(4-pyridyl)ethane by reactive halogenated derivatives in anhydrous solvent under reflux conditions, MW and US irradiation reduced the reaction time and the desired products were achieved in a few min. One of the aims of this study was to evaluate the antibacterial potential of the synthesized QAs against pathogenic bacteria, along with their impact on germination activity of wheat seeds (Triticum aestivum L.). The antibacterial activity of the QAs against Escherichia coli was explored by determining the minimum inhibitory concentration (MIC). The MIC values varied from 0.312 to 2.5 mg/mL, highlighting the lowest values attained for the derivatives containing methoxy, chlorine and benzofurane functional groups. The viability of aerobic bacteria was determined with the Tetrazolium/Formazan Test, a method that was found to be the best alternative approach with respect to the difuzimetric method. Seeds of Triticum aestivum L. were used for the evaluation of the germination indicators, such as seed germination (SG), the relative seed germination (RSG), the relative radicle growth (RRG), and the seed germination index (GI). The toxicity studies of QAs 1, 4 and 7, at two different concentrations, showed no inhibitory effect on seed germination.

Department of Chemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia Department of Chemistry, Physics, and Environment, Faculty of Sciences and Environment, “Dunarea de Jos” University of Galati, 111 Domneasca Street, Galati 800201, Romania Department of Applied Chemistry, Aligarh Muslim University, Aligarh 202001, India School of Materials Science and Engineering, Changwon National University, Changwon 51140, Republic of Korea

This paper reports the synthesis and characterization of six new coordination polymers having the following stoechiometric formulations: Ag2(tr2ad)(NO3)2·H2O (1), Ag3(tr2ad)2(ClO4)3·EtOH (2), Ag(tr2ad)(PF6)·H2O (3), Ag3(tr2ad)2(BF4)3·H2O (4), Ag2(tr2ad)(CH3SO3)2·3H2O (5) and Ag3(tr2ad)2(CF3SO3)3·EtOH (6) (EtOH = ethanol). The compounds were obtained from the interaction between the 1,3-bis(1,2,4-triazol-4-yl) adamantane ligand (tr2ad) and silver(I) salts with different counteranions, in alcoholic ambient at room temperature. All the compounds are airand moisture-stable, insoluble in most common solvents and do not melt, but only decompose upon heating to high temperatures, thus suggesting their polymeric nature. Fourier transform infrared spectroscopy (FTIR) was employed in order to reveal both the changes in the absorbtion bands of the ligand upon coordination to silver(I) ions and the binding modes of the counteranions.

The comparative effect of two quaternary ammonium salts from 1,2-bis(4-pyridyl)ethane (PyQAs), namely N,N′-diphenacyl-1,2-bis(4-pyridinium)ethane dibromide (PyQAs1) and N,N′-di(p-methoxyphenacyl)-1,2-bis(4-pyridinium)ethane dibromide (PyQAs2), upon the size and photoluminescence of zinc oxide nanoparticles (ZnO NPs) was investigated. The formation of ZnO NPs took place in the presence of variable amounts of the two PyQAs species (1, 2.5, and 5%), according to the chemical precipitation of zinc(II) acetate with potassium hydroxide in ethanol under reflux. The obtained ZnO NPs were structurally characterized by means of X-ray powder diffraction, infrared, and Raman spectroscopy. The fluorescence of all supernatant solutions, observed under ultraviolet light, determined us to make an investigation of the solutions by means of liquid chromatography coupled with electrospray ionization mass spectrometry (LC-MS-ESI) in order to elucidate the identity of the newly formed fluorescent species. Such an occurrence thus allowed the invocation of the catalytic effect of zinc(II) ions towards the organic transformation of both nonfluorescent PyQAs surfactants into new fluorescent organic species.