نتایج جستجو برای: vis spectroscopy
تعداد نتایج: 187793 فیلتر نتایج به سال:
in this study silver/poly vinyl alcohol (pva) and silver/poly vinyl pyrrolidone (pvp) nanocomposites were prepared via reduction of silver salt by employing dmf (n, n`- dimethyl formamide) as a reducing agent. effects of protective agents such as pva and pvp were also described here. we show that the acidic ph of pvp solution also affects the interaction between protective agents and silver nan...
Tm-doped TiO2 nanoparticles were synthesized using a water-controlled hydrolysis reaction. Analysis was performed in order to determine the influence of the dopant concentration and annealing temperature on the phase, crystallinity, and electronic and optical properties of the resulting material. Various characterization techniques were utilized such as X-ray diffraction, Raman spectroscopy, X-...
BACKGROUND PURPOSE Photocatalytic water splitting for hydrogen evolution is a potential way to solve many energy and environmental issues. Developing visible-light-active photocatalysts to efficiently utilize sunlight and finding proper ways to improve photocatalytic activity for H2 evolution have always been hot topics for research. This study attempts to expand the use of sunlight and to enha...
Two water-soluble zinc complexes, [Zn(L)Cl(2)] (1) and [Zn(2)(L)(2)(μ-C(2)O(4))(H(2)O)(2)]·(ClO(4))(2)·CH(3)OH (2) (L = N,N-bis(2-pyridylmethyl)methylamine), were prepared to serve as nuclease mimics. The complexes were characterized by X-ray, IR and UV-vis spectroscopy as well as ESI-MS. The electrospray mass spectrum of 2 in solution indicates that dinuclear ion [Zn(2)(L)(2)(μ-C(2)O(4))(ClO(4...
In this research, the dinuclear Zn(ii) complex of anthracene based tripodal tetramine Zn2L was synthesized, and its sensing abilities towards anions was investigated using the indicator displacement assay (IDA) approach with four complexometric indicators: pyrocatechol violet (PV), bromopyrogallol red (BPG), methylthymol blue (MTB) and xylenol orange (XO). UV-vis spectrophotometry results indic...
A new heterogeneous catalyst for CO(2) activation was identified in the Cr(II)/SiO(2) Phillips catalyst, one of the most important catalysts used industrially for olefin polymerization. Interestingly, it was found that Cr(II)/SiO(2) strongly activates CO(2) already at room temperature, making it available for chemicals synthesis. A preliminary attempt in this direction was done by following the...
Biofunctionalized silicon quantum dots were prepared through a one step strategy avoiding the use of chemical precursors. UV-Vis spectroscopy, Raman spectroscopy and HAADF-STEM prove oligonucleotide conjugation to the surface of silicon nanoparticle with an average size of 4 nm. The nanoparticle size results from the size-quenching effect during in situ conjugation. Photoemissive properties, co...
The synthesis of a heterocyclic mesomeric betaine by quaternization reaction of 1-butylimidazole and tetrabromo-1,4-benzoquinone is presented. The structure was verified by means of X-ray single-crystal analysis, NMR and IR spectroscopy. Inclusion complexes of the heterocyclic mesomeric betaine with randomly methylated (1.8) β-cyclodextrin were investigated by UV-vis spectroscopy. Furthermore, ...
The synthesis and magnetic properties of Ni nanoparticles containing <150 atoms are described. These materials are prepared in an organic solvent using hydrophobic dendrimers as templates, which results in a high degree of size monodispersity. The dendrimer-encapsulated nanoparticles were characterized by UV-vis spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy....
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