Phthalocyanine macrocycle as stabilizer for gold and silver nanoparticles

A one-step process was used for the preparation of gold and silver nanoparticles stabilized by an aminophthalocyanine macrocycle. The resultant nanoparticles were characterized by absorption spectra, infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The nanoparticles were found to possess relatively narrow size distribution. The gold nanoparticles have an average diameter of ~2 nm, while silver particles have 4-5 nm. Preliminary studies on fluorescence and surface enhanced Raman spectroscopy were carried out using these nanoparticles. Fluorescence studies indicate that gold nanoparticles do not quench the fluorescence, while silver nanoparticles do. The stabilized nanoparticles showed enhancement of the Raman signals, thus revealing that they are good substrates for surface enhanced Raman scattering studies

Phthalocyanine macrocycle as stabilizer for gold and silver nanoparticles

A one-step process was used for the preparation of gold and silver nanoparticles stabilized by an aminophthalocyanine macrocycle. The resultant nanoparticles were characterized by absorption spectra, infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The nanoparticles were found to possess relatively narrow size distribution. The gold nanoparticles have an average diameter of similar to 2 nm, while silver particles have 4-5 nm. Preliminary studies on fluorescence and surface enhanced Raman spectroscopy were carried out using these nanoparticles. Fluorescence studies indicate that gold nanoparticles do not quench the fluorescence, while silver nanoparticles do. The stabilized nanoparticles showed enhancement of the Raman signals, thus revealing that they are good substrates for surface enhanced Raman scattering studies

An Agro-Waste Catalyzed Facile Synthesis of 1<i>H-</i>Pyrazolo[1,2-b]Phthalazine-5,10-Dione Derivatives: Evaluation of Antioxidant and Electrochemical Studies

Rapid and inexpensive one-pot multicomponent synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione through a condensation reaction of aryl aldehyde, malononitrile or ethyl cyanoacetate and phthalhydrazide catalyzed by water extract of papaya bark ash (WEPBA) solvent medium under microwave irradiation is described. The catalytic medium is used environmentally friendly, and provides several benefits of being simple, inexpensive, high yield, simple work-up and not required hazardous solvent for the reaction. Some of the selected derivatives were characterized by FT-IR, 1H-, and 13C-NMR, and mass spectrometry techniques. The oxidation-reduction properties of the synthesized compounds (4b, 4e, 4f, 4i, and 4k and 6f, 6g, 6h, 6i, and 6j) were studied using cyclic voltammetry (CV). The voltammetry peak current for the oxidation-reduction of the compounds examined at different scan rates. Further, some of the selected 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives were evaluated in vitro antioxidant activity using DPPH assay method. The result appears that, compounds 4b, 4e, 4i, 6f, 6g, and 6h possess significant antioxidant properties in comparison with the ascorbic acid reference.</p

Self Assembled Films of Porphyrins with Amine Groups at Different Positions: Influence of Their Orientation on the Corrosion Inhibition and the Electrocatalytic Activity

Self-assembled molecular films of two cobalt porphyrins with amine groups at different positions—(5,10,15,20-tetrakis-(2-aminophenyl) porphyrin-cobalt(II), [Co(II) (T(o-NH&lt;sub&gt;2&lt;/sub&gt;)PP)] and (5,10,15,20-tetrakis-(4-aminophenyl) porphyrin-cobalt(II), [Co(II)(T(p-NH&lt;sub&gt;2&lt;/sub&gt;)PP)]—were formed on a gold substrate. The functionalized surfaces were characterized using Raman spectroscopy, atomic force microscopy and electrochemical methods. Both modified gold surfaces completely mask the charge transfer of a [Fe(CN)&lt;sub&gt;6&lt;/sub&gt;]&lt;sup&gt;3−/4−&lt;/sup&gt; redox couple in solution, indicating the layer is highly resistive in behavior. Electrochemical impedance spectroscopy analyses revealed that the porphyrin film with amine groups at &lt;em&gt;ortho&lt;/em&gt; positions shows a higher charge-transfer resistance with a better protective behavior compared to the &lt;em&gt;para&lt;/em&gt; position modified surface. Raman, AFM and EIS data suggests that an &lt;em&gt;ortho&lt;/em&gt; amine positioned molecule forms a more compact layer compared to the &lt;em&gt;para&lt;/em&gt;-positioned molecule. This can be explained in terms of their orientation on the gold surface. [Co(II)(T(o-NH&lt;sub&gt;2&lt;/sub&gt;)PP)] adopted a saddle shape orientation whereas [Co(II)(T(p-NH&lt;sub&gt;2&lt;/sub&gt;)PP)] adopted a flat orientation on the gold surface. The porphyrin modified gold electrode catalyzes the oxygen reduction at lower potentials compared to the bare gold electrode. The shift in the overvoltage was higher in case of molecules with flat orientation compared to the saddle shaped oriented porphyrin molecules on the surface

One-step vs stepwise immobilization of 1-d coordination-based rh-rh molecular wires on gold surfaces.

Reaction of dimeric [Rh(II)(2)(phen)(2)(μ-OAc)(2)(MeCN)(2)](BF(4))(2) (phen =1,10-phenanthroline) with pyrazine (pz) in a 1:2 ratio leads to the new 1-D metal-metal-bonded coordination oligomer {[Rh(II)(2)(phen)(2)(μ-OAc)(2)(pz)](BF(4))(2)}(n) (Rh-Rhpz)(n) (1), where each Rh atom of the dimeric unit (Rh-Rh) is coordinated in the equatorial plane to a nitrogen atom of a rigid and linear bifunctionalized organic linker (pz). Single X-ray diffraction analysis reveals the 1-D straight oligomeric chain structure (molecular wire, MW) consists of alternating (Rh-Rh) units and pz linking ligands with free BF(4)(-) as counteranions, and each metal center has a slightly distorted octahedral arrangement. The presence of accessible labile MeCN groups on both ends of these MWs ("free ends") enables functionalization of a 4-mercaptopyridine-gold coordinating platform (Au/MP) to form in one step a layer of coordination oligomer (Au/MP(Rh-Rhpz)(n); n ≈ 50). Furthermore (Rh-Rhpz)(n) (n = 1-6) MWs were grafted to Au/MP surfaces by a conventional step-by-step assembly construction involving coordination reactions between the Rh dimer ([Rh(2)(phen)(2)(μ-OAc)(2)(MeCN)(2)](BF(4))(2) (2)) and pz. A detailed physicochemical study (UV-vis, RAIR, QCM-D, ellipsometry, contact angle measurements, as well as impedance spectroscopy and cyclic voltammetry) has been made during both assembly methods to characterize the resulting surface-anchored coordination molecular wire (CMW) layers (Au/MP(Rh-Rhpz)(n)). The results indicate that the immobilized molecular assemblies (MAs) were successfully fabricated using both methods of assembly. The efficiency of the two methods is discussed

Unlocking the effect of Zn2+ on crystal structure, optical properties, and photocatalytic degradation of perfluoroalkyl substances (PFAS) of Bi2WO6

Bismuth tungstate (Bi2WO6) with a layered structure and visible light response exhibits excellent photocatalytic activity. To enhance its photocatalytic activity for the degradation of perfluoroalkyl substances (PFAS), Zn2+ is partially substituted for Bi3+ in the Bi2WO6 lattice in this study. Particularly, the effect of Zn2+ content (0-22.5 at%) on the crystal structure, optical property, and photocatalytic activity for the photodegradation of PFAS of Bi2WO6 is investigated. According to the Le Bail fits, the unit-cell volume is slightly reduced from 487.7 Å3 to 480.8 Å3 by the partial substitution of smaller Zn2+ (0.74 Å for CN = 6) for larger Bi3+ (1.03 Å for CN = 6) in the Bi2WO6 crystal lattice, and the solubility of Zn2+ in the Bi2WO6 lattice is found to be below 17.5 at%. The partial substitution of Zn2+ influences the self-aggregation of nanoparticles, Ostwald ripening, and self-organization of nanoplates, resulting in different morphologies. Although the optical bandgap energy of Bi2WO6 is not significantly altered upon the partial substitution of Zn2+, the conduction and valence bands simultaneously shift upward. Among the Bi2−xZnxWO6+δ photocatalysts, 2.5 at% Zn2+-substituted Bi2WO6 exhibits larger water oxidation photocurrent density (0.316 mA cm−2 at 1.23 VRHE) and the highest photocatalytic activity for the photodegradation of PFHxA (k1 = 0.012 min−1). The trapping experiments confirm that the photo-excited holes (h+) and superoxide radicals (O2˙−) are the major reactive species involved in the photodegradation of PFHxA. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) reveals that decarboxylation and defluorination are the main possible routes for the photodegradation of PFHxA over Bi2−xZnxWO6+δ photocatalysts. Our findings suggest that the partial Zn2+-to-Bi2+ substitution can enhance the photocatalytic activity of Bi2WO6 for the degradation of PFAS.Fil: Hojamberdiev, Mirabbos. Technishe Universitat Berlin; AlemaniaFil: Larralde, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnologia Industrial. Gerencia Operativa de Desarrollo Tecnologico E Innovacion. Sub Gerencia Operativa de Energia y Movilidad.; ArgentinaFil: Vargas Balda, Ronald Eduardo. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Madriz Ruiz, Lorean Mercedes. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; ArgentinaFil: Yubuta, Kunio. Kyushu University; JapónFil: Sannegowda, Lokesh Koodlur. Vijayanagara Sri Krishnadevaraya University; IndiaFil: Sadok, Ilona. Medical University Of Lublin (medical University Of Lublin);Fil: Krzyszczak Turczyn, Agnieszka. Medical University Of Lublin (medical University Of Lublin); . Maria Curie-Skłodowska University in Lublin; PoloniaFil: Oleszczuk, Patryk. Medical University Of Lublin (medical University Of Lublin); . Maria Curie-Skłodowska University in Lublin; PoloniaFil: Czech, Bożena. Medical University Of Lublin (medical University Of Lublin); . Maria Curie-Skłodowska University in Lublin; Poloni