Fabrication of Nanosized Cuprous Oxide Using Fehling's Solution

A facile method for the synthesis of Cu2O nanoparticles by reduction of Fehling's solution, using glucose as reducing agent. Copper sulfate is used as a precursor with potassium sodium tartarate in an alkaline media to produce Fehling's solution. The precipitation of Cu2O nanoparticles from this solution in the presence of glucose was controlled by addition of SLES or Triton-X 100 as surfactants. The reactions have been carried out at 60_C with high repeatability. The purification process of the Cu2O product does not require expensive methods, since a solid product isobtained from a reaction in liquid phase.

Materials

1. 1   CuSO4.5H2O,
2. 2    Potassium sodium tartarate tetrahydrate,
3. 3    Triton-X 100,
4. 4    Sodium laureth sulfate
5. 5    NaOH analytical grade

Preparation of Cu2O Nanoparticles

Fehling's solution which is comprised of equal parts of the following solutions was first made:

Solution 1: Was made by dissolving of copper (II) sulfate pentahydrate (6.9 g 0.02 mol) in distilled water (100 mL).

Solution 2: Was made by dissolving of potassium sodium tartarate tetrahydrate (34.6 g) and sodium hydroxide (12 g) in distilled water (100 mL).

50 mL of each of the above solutions were mixed together in a beaker and Triton X-100 or SLES (2 g) was added to the mixture and vigorously stirred for 15 m. To this mixture, aqueous solution containing 5 g of glucose in 50 mL water was added and the whole content was then heated at 60° under continuous stirring. A brick-red solid of Cu2O precipitated after a short period of reaction time. The solid was filtered off, washed with deionized water (3 times) and ethanol (2 times) and it was dried in an oven at 80°C for 3 h to afford nanosized Cu2O, 1.38 g (97% yield based n the used copper sulfate; each mole of copper sulfate produces 0.5 mole of Cu2O).

Tomado de :

Fabrication of Nanosized Cuprous Oxide Using Fehling's Solution

M. Kooti  and L. Matouri

Transaction F: Nanotechnology

Vol. 17, No. 1, pp. 73-78

Facile preparation of water-soluble fluorescent gold nanoclusters

A simple one-pot strategy of preparing small fluorescent AuNCs using a mild reductant, tetrakis-
(hydroxymethyl)phosphonium chloride (THPC). For biological imaging applications, a zwitterionic functional ligand, D-penicillamine (DPA), was chosen as a capping agent to endow the gold clusters with good stability in aqueous solvent.

Materiales


1. Tetrakis(hydroxymethyl) phosphonium chloride (THPC, P(CH2OH)4Cl, 80% aqueous solution),
2. D-penicillamine (DPA),
3. Rhodamine 6G
4. Gold(III) chloride trihydrate (HAuCl4.3H2O)
5. Sodium borohydride (NaBH4)
6. High purity deionized water

Síntesis


12 ml THPC (80%) was added to 47 ml NaOH solution (6 mM) at 37 C. The mixture was stirred for 3
min, followed by rapid addition of a solution of HAuCl4 (0.67ml, 2% by mass) and DPA (2.5 ml, 0.1 M). The reaction, during which the colorless solution slowly turned light yellow, was stopped after stirring for 15 h.


As-prepared AuNCs were purified by triple centrifugation filtration, using Nanosep filters (PallNanosep, Ann Arbor, MI) with a molecular weight cut-off of 3 kDa to remove impurities. The yellowish DPA–AuNCs
remaining on the filter could be re-suspended readily in water,and the solution was stored at 4 C for later use

Tomado de:


Facile preparation of water-soluble fluorescent gold nanoclusters for cellular imaging applications

Li Shang,a Ren e M. D€orlich,a Stefan Brandholt,a Reinhard Schneider,b Vanessa Trouillet,c Michael Bruns,c
Dagmar Gerthsenb and G. Ulrich Nienhaus

Nanoscale, 2011, 3, 2009

http://dx.doi.org/10.1039/c0nr00947d

Preparation of Silver Nanoparticles

Uniform silver nano particles can be obtained through the reduction of silver ions by ethanol at a temperature of
80°C to 100°C under atmospheric conditions [4]. In this synthesis process, 20 ml of aqueous solution containing silver nitrate (0.5g of AgNO3), 1.5 g sodium linoleate (C18H32ONa), 8 ml ethanol and 2 ml linoleic acid (C18H32O2) are added in a capped tube under agitation. The system is sealed and treated at the temperatures between 80°C to100°C for 6 hours.

Materiales

1.       silver nitrate   à 5g

2.       sodium linoleate à 15 g

3.       Ethanol à 50 mL

4.       linoleic acid à 50 mL

TTomado de:

PPreparation of Silver Nanoparticles and 

Their Characterization

R. Das, S. S. Nath, D. Chakdar, G. Gope, R. Bhattacharjee

www.azonano.com/oars.asp

Preparation and Properties of Colloidal CdSe Quantum Dots

Objective:

             CdSe quantum dots will be synthesized anaerobically from elemental selenium and cadmium oxide.  The resulting quantum dots will be characterized by their emission properties.

Experimental:

            The synthesis of quantum dots requires a nucleation step, separate from dot growth.  To achieve a complete nucleation, solutions of Se and CdO are prepared separately and then combined.  Preparation of CdO solution:  A 25mL 3-neck round bottom flask is equipped with a stir bar and a septum in all three ports.  The top port is used to purge and vent the system with Ar, the left port is equipped with a temperature probe attached to a digital thermometer, and the right port is used for addition of reagents.  0.100mmol (0.0127g) of CdO and 0.400mmol (0.1140g) of stearic acid are added to the round bottom flask and heated, with a heating mantle, to 150°C until the CdO has fully dissolved.  Reaction is cooled to about room temperature and 5.017mmol (1.9400g) of trioctylphosphine oxide (TOPO) and 8.035mmol (1.9400g) of hexadecylamine (HDA) are added to the flask.  Reaction is heated to 320°C and becomes optically clear.  Preparation of Se Solution:  To a 15mL side arm pear shaped flask equipped with a stir bar, 1.000mmol (0.0790g) of selenium powder, and 2.10mL of dioctylamine are added.  The side arm is equipped with a screw top cap and Teflon seal facing the inside of the flask, so as to keep material from clumping in the side arm.  The top of the flask is equipped with a septum and an Argon inlet-needle, and a vent needle.  The reaction flask is purged for 10min with Ar.  A 1mL syringe with a 4” stainless steel needle is purged with Ar and then used to remove 0.290mL of tributylphosphine (TBP) from a sure seal bottle.  The TBP is then injected into the flask via the Teflon coated disk on the side arm. Combination of Solutions:  Once the CdO solution has reached 320°C the entire Se solution is added using a 5mL glass syringe with a 4” stainless steel needle.  The reaction temperature is reduced to 290°C and ≈5µL aliquots are removed at 2sec, 40sec, 90sec, 130 sec, 310sec, and 600sec; each aliquot is diluted to 3mL with chloroform in a microfuge tube.  After ten minutes the reaction is cooled to room temperature and 15mL of chloroform is added to the reaction.  Reaction purification and data collection:  The final reaction mixture is transferred equally into two 15mL centrifuge tubes and centrifuged at max speed for 20min.  The supernatant is collected and centrifugation is repeated until the resulting supernatant is clear.  Once optically clear the QD’s were precipitated by adding methanol into the chloroform solution and isolated by centrifugation and decantation.  The aliquots collected and diluted in microfuge tubes are used without further purification and UV-Vis data is obtained from 350-700nm.  Samples are diluted so that they have an optical density at the first excition absorption peak below .1 in order to avoid any signicant reabsorption; fluorescence emission data is obtained.

References:

Qu, L.; Peng, X.  J. Am. Chem. Soc. 2002, 124, 2049.

Propósito

Podemos usar este blog para organizar la discusión de los posibles experimentos que se realizarían en el Taller Práctico Experimental  de la escuela de NanoAndes 2012. Todos los participantes pueden:

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