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Inorganic nanoparticles (NPs) have been proposed as alternative fertilizers to suppress plant disease and increase crop yield. However, phytotoxicity of NPs remains a key factor for their massive employment in agricultural applications. In order to investigate new effective, nonphytotoxic, and inexpensive fungicides, in the present study CuZn bimetallic nanoparticles (BNPs) have been synthesized as antifungals, while assessment of photosystem II (PSII) efficiency by chlorophyll fluorescence imaging analysis is utilized as an effective and noninvasive phytotoxicity evaluation method. Thus, biocompatible coated, nonoxide contaminated CuZn BNPs of 20 nm crystallite size and 250 nm hydrodynamic diameter have been prepared by a microwave-assisted synthesis. BNPs' antifungal activity against Saccharomyces cerevisiae was found to be enhanced compared to monometallic Cu NPs. Reactive oxygen species (ROS) formation and photosystem II (PSII) functionality at low light (LL) and high light (HL) intensity were determined on tomato plants sprayed with 15 and 30 mg L of BNPs for the evaluation of their phytotoxicity. Tomato leaves sprayed with 15 mg L of BNPs displayed no significant difference in PSII functionality at LL, while exposure to 30 mg L of BNPs for up to 90 min resulted in a reduced plastoquinone (PQ) pool that gave rise to HO accumulation, initiating signaling networks and regulating acclimation responses. After 3 h of exposure to 30 mg L of BNPs, PSII functionality at LL was similar to control, indicating nonphytotoxic effects. Meanwhile, exposure of tomato leaves either enhanced (15 mg L) or did not have any significant effect (30 mg L) on PSII functionality at HL, attributed to the absence of semiconducting oxide phases and photochemical toxicity-reducing modifications. The use of chlorophyll fluorescence imaging analysis is recommended as a tool to monitor NPs behavior on plants.

A facile selective synthesis of Cu2O and heterogeneous Cu/Cu2O nanoparticles (NPs) was achieved through a solvothermal approach by Cu(NO3)2 in proportion of three different surfactants, namely, tetraethylene glycol (TEG), oleylamine (OAm) and polyoxyethylene (20) sorbitan laurate (Tween 20). Formation aspects for the spherical Cu2O@OAm (30 nm) and Cu2O@Tween (12 nm) as well as for the core-shell and semishell Cu/Cu2O@TEG NPs (7 nm) and the Cu/Cu2O@OAm (170 nm) nanorods have been proposed. The fungistatic and fungicidal activity of the newly synthesized NPs was studied in vitro against the yeast Saccharomyces cerevisiae, which constitutes a unicellular eukaryotic model microorganism in molecular and cell biology. The antifungal results, based on optical density and fluorescence measurements, clearly indicate that the composition, size, and amount of surfactant are of key importance in the antifungal properties of the NPs. Cu2O@OAm NPs exhibited the most prominent antifungal activity with 3.73 μg/mL IC(50viability) value. The isolated DNA of S. cerevisiae cells after exposure to the NPs was investigated, and binding and/or degradation phenomena were recorded that are correlated to the size and concentration of the NPs. Their activity pathway was further explored, and reactive oxygen species production and lipid peroxidation were verified mainly for Cu2O NPs.

Metallamacrocyles have been intensively studied over the past decade. These molecules have already been used in applications as diverse as catalysis, [1] sensors, [2] or as chiral building blocks for two-and three-dimensional solids. [3] Metallamacrocyles include complexes such as metallacrowns, [3, 4] molecular squares, [1,2] metallacalixarenes, [5] and metallahelicates. [6] Metallacrowns (MC), the inorganic structural and functional analogs to crown ethers, are usually formed with transition-metal ions incorporated into the metallamacrocyclic ring, thus providing the attractive feature that they concentrate a large number of metal ions per unit volume. This large metal-ion concentration may lead to interesting magnetic behavior. [4,7] Since the recognition of single-molecule magnets (SMMs) in 1993, the field has gained considerable attention as a study of both classical and quantum effects. [8,9] SMMs of cobalt, [10] vanadium, [11] nickel, [12] iron, [13] and a mixed-metal system [14] have been studied. However, the best known and most intensely studied SMMs are the manganese carboxlyate clusters, which range in size from Mn 4 to Mn 30 . [15] Herein we report the synthesis (Scheme 1) and characterization of the second [16]