Fluorescence Characteristics of Highly-Pure Nanoparticles Embedded in Dye Complexes for Random Laser Design

In this work, highly-pure titanium dioxide nanoparticles produced by dc magnetron sputtering technique were embedded in organometallic complex solutions such as Baq2 or Znq2 to form random gain media. The structural characteristics of the TiO2 nanoparticles were determined to confirm their high structural purity. The spectroscopic characteristics, mainly photoluminescence and fluorescence, of the complex solutions containing the nanoparticles were determined and studied. These media were compared to two of the most common laser dyes (Rhodamine b and Rhodamine 6G) to determine the feasibility to use them to produce random laser.

A Comprehensive Experimental and Theoretical Study on the [{(η5-C5H5)2Zr[P(µ-PNEt2)2P(NEt2)2P]}2O Crystalline System

The structure of tetraphosphetane zirconium complex C52H100N8OP10Zr2 1 was determined by single crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c, with a = 19.6452(14), b = 17.8701(12), c = 20.7963(14)Å, α = γ = 90°, β = 112.953(7)°, V = 6722.7(8)Å3, Z = 4. The electronic structure of the organometallic complex has been characterized within the framework of Quantum Chemical Topology. The topology of the Electron Localization Function (ELF) and the electron density according to the Quantum Theory of Atoms in Molecules (QTAIM) show no covalent bonds involving the Zr atom, but rather dative, coordinate interactions between the metal and the ligands. This is the first reported case of a Zr complex stabilized by an oxide anion, anionic cyclopentadienyl ligands and rare tetraphosphetane anions.

Concentration Effect over Thermoresponse Derived from Organometallic Compounds of Functionalized Poly(N-isopropylacrylamide-co-dopamine Methacrylamide)

The functionalization of smart polymers is opening a new perspective in catalysis, drug carriers and biosensors, due to the fact that they can modulate the response regarding conventional devices. This smart response could be affected by the presence of organometallic complexes in terms of interactions which could affect the physical chemical properties. In this sense, the thermoresponsive behavior of copolymers based on N-isopropylacrylamide (NIPAM) could be affected due to the presence of hydrophobic groups and concentration effect. In this work, the functionalization of a copolymer based on NIPAM and dopamine methacrylamide with different amounts of bis(cyclopentadienyl)titanium (IV) dichloride was carried out. The resulting materials were characterized, showing a clear idea about the mechanism of functionalization through FTIR spectroscopy. The thermoresponsive behavior was also studied for various polymeric solutions in water by UV–vis spectroscopy and calorimetry. The hydrophobic interactions promoted by the organometallic complex could affect the transition associated with the lower critical solution temperature (LCST), specifically, the segments composed by pure NIPAM. That fact would explain the reduction of the width of the LCST-transition, contrary to what could be expected. In addition, the hydrophobicity was tested by the contact angle and also DNA interactions.

Alternate layer by layered self assembly of conjugated and unconjugated Salen based nanowires as capacitive pseudo supercapacitor

A novel electrosynthetic method has been introduced based on alternate layer-by-layered self-assembly of conjugated/unconjugated Salen-based nanowires as a capacitive pseudo-supercapacitor. For this purpose, a three-electrode system consisted of a glassy carbon (GC), Ag/AgCl (Sat’d Cl−) and a Pt rod as working, reference, and counter electrodes, respectively. The electrolyte included the same molar concentration (0.040 mol L−1) of each Salen monomer (as initial precursor), and KCl solution (as supporting electrolyte), besides using KOH solution (0.01 mol L−1, as basic-controlling reagent) inside acetone/water (4:1, V/V) as a solvent. The formation of this self-assembly nanowire was attributed to the control of the electrical conductivity of this polymer during formation of an organometallic complex with K+ as responsible complex forming agent. This novel nanowire then played role as a capacitive pseudo-supercapacitor. Based on the chrono—potentiometry, reproducible charge/discharge process for at least 5000 cycles was observed at a potential between − 2.00 and + 1.75 V (vs. Ag/AgCl). The capacity behavior of the polymer was also evidenced using electrochemical impedance spectroscopy. This synthesized polymeric nanowire was adopted as the acceptable pseudo-supercapacitor with real capacity equals to 3110 ± 6 (n = 3) C g−1. This study was considered as the first report at which the self—assembly of organometallic compounds as an efficient pseudo—supercapacitor was introduced.

2-Phenylimidazole Corrosion Inhibitor on Copper: An XPS and ToF-SIMS Surface Analytical Study

This work presents a surface analytical study of the corrosion inhibitor 2-phenylimidazole (2PhI) adsorbed on a Cu surface from 3 wt.% NaCl solution. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to investigate the surface phenomena. Various XPS experiments were performed, i.e., survey- and angle-resolved high-resolution XPS spectra measurements, gas cluster ion beam sputtering in conjunction with XPS measurements, and XPS imaging in conjunction with principal component analysis. These measurements were used to detail the composition of the surface layer at depth. In addition, various ToF-SIMS experiments were performed, such as positive ion ToF-SIMS spectral measurements, ToF-SIMS imaging, and cooling/heating in conjunction with ToF-SIMS measurements. This study shows that organometallic complexes were formed between 2PhI molecules and Cu ions, that the surface layer contained entrapped NaCl, that the surface layer contained some Cu(II) species (but the majority of species were Cu(I)-containing species), that the surface was almost completely covered with a combination of 2PhI molecules and organometallic complex, and that the temperature stability of these species increases when 2PhI is included in the organometallic complex.

Exploring Electron-Sink Behaviors of Molecular Assemblies

Metal carbonyl clusters, such as the [Ni32C6(CO)36]6- anion, have been documented to display electron-sink phenomena. However, such large clusters suffer from inefficient yields due to their demanding and unreliable synthesis routes. To approach this obstacle, we investigated the electrochemical properties of Fe2(μ-PPh2)2(CO)6, an organometallic complex known to experience a reversible two-electron transfer process. In this work, we report a modular synthetic strategy for expanding the electron-sink capacity of molecular assemblies by installing Fe2(μ-PPh2)2(CO)6 redox mediators to arylisocyanide ligands. Specifically, the coordination of three Fe2(μ-PPh2)2(CO)6 subunits to a trifunctional arylisocyanide ligand produces an electron-sink ensemble that can accommodate six electrons, exceeding the precedent benchmark [Ni32C6(CO)36]6- anion. The redox mediators store electrons within quantized unoccupied frontier orbitals and act as individual quantum capacitors. Ultimately, we propose to modify the electrode surfaces with these redox mediators to examine the relationship between the electrode’s mesoscopic structure and its macroscopic capacitance.

A platform for on-the-complex annulation reactions with transient aryne intermediates

Organometallic complexes are ubiquitous in chemistry and biology. Whereas their preparation has historically relied on ligand synthesis followed by coordination to metal centers, the ability to efficiently diversify their structures remains a synthetic challenge. A promising yet underdeveloped strategy involves the direct manipulation of ligands that are already bound to a metal center, also known as chemistry-on-the-complex. Herein, we introduce a versatile platform for on-the-complex annulation reactions using transient aryne intermediates. In one variant, organometallic complexes undergo transition metal-catalyzed annulations with in situ generated arynes to form up to six new carbon–carbon bonds. In the other variant, an organometallic complex bearing a free aryne is generated and intercepted in cycloaddition reactions to access unique scaffolds. Our studies, centered around privileged polypyridyl metal complexes, provide an effective strategy to annulate organometallic complexes and access complex metal–ligand scaffolds, while furthering the synthetic utility of strained intermediates in chemical synthesis.

QUANTITATIVE INDICATORS OF COPPER-RESISTANT MICROORGANISMS DISTRIBUTION IN NATURAL ECOSYSTEMS

Copper is a highly toxic metal common in both natural and man-made ecosystems. The goal of the work was to determine the level of resistance of microorganisms of natural ecosystems to cationic form and organometallic complex of Cu2+. Microorganisms of 9 natural ecosystems of five geographic zones (the Antarctic, the Arctic, the Dead Sea (Israel), middle latitude (Ukraine) and the equatorial zone of South America (Ecuador) were investigated. Resistance of microorganisms was determined by cultivation in the medium with concentration gradient of Сu2+. The amount of Cu2+-resistant microorganisms in natural ecosystems was determined by colony counting on nutrient agar with Сu2+ citrate and Cu2+ cation. The Cu(II) concentration in soil and clay samples was analyzed by atomic absorption spectroscopy method. We have confirmed the hypothesis that microorganisms resistant to toxic Cu2+ compounds in high concentrations exist in any natural ecosystem. The resistance to Cu2+ cation was 8 – 31 and 14 –140 times less than to Cu2+ citrate in nutrient and mineral agar media respectively. The amount of Cu2+-resistant microorganisms in natural ecosystems reached hundreds and thousands at the presence of 175…15 500 ppm Cu2+. Thus, the soils, clays and sands of natural ecosystems are a “genetic resource” of copper-resistant microorganisms that are promising for development of novel biotechnology of purification of copper-containing wastewater and soil bioremediation.