Synthesis of CdS and CdSe nanoparticles by thermolysis of diethyldithio- or diethyldiseleno-carbamates of cadmium

Cadmium sulfide and cadmium selenide nanoparticles have been synthesised by a novel route involving the thermal decomposition of the bisdiethyldithio- or bisdiethyldiseleno-carbamates of cadmium in refluxing 4-ethylpyridine solutions. The nanodispersed materials were studied by electronic spectroscopy and bandgaps were blue shifted. Transmission electron microscopy of the samples showed material to be in the nanosize range and crystalline

Developing a coordination chemistry of intact quantum dots: the preparation of novel nanocomposites of PbS with CdS or CdSe

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Preparation of zinc-oxide and zinc-sulfide powders by controlled precipitation from aqueous-solution

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Synthesis of PbS nanocrystallites using a novel single molecule precursors approach: X-ray single-crystal structure of Pb(S2CNEtPri)2

The synthesis and characterisation of some lead(II) dithiocarbamato complexes Pb(S2CNRR¾)2 is reported. These compounds were used as single molecule precursors to produce nanocrystalline PbS by their thermolysis in trioctylphosphine oxide. The optical and morphological properties of the resulting PbS nanocrystallites were investigated; the influence of experimental parameters, such as precursor, growth time and temperature, on the final nanodispersed materials is also reported

Use of dialkyldithiocarbamato complexes of bismuth(III) for the preparation of nano- and microsized Bi2S3 particles and the X-ray crystal structures of [Bi{S2CN(CH3)(C6H13)}(3)] and [Bi{S2CN(CH3)(C6H13)}(3)(C12H8N2)]

A range of bismuth(III) dithiocarbamato complexes were prepared and characterized. The X-ray crystal structures of the compounds [Bi{S2CN(CH3)(C6H13)}3] (1) and [Bi{S2CN(CH3)- (C6H13)}3(C12H8N2)] (2) are reported. The preparation of Bi2S3 particulates using a wet chemical method and involving the thermalysis of Bi(III) dialkyldithiocarbamato complexes is described. The influence of several experimental parameters on the optical and morphological properties of the Bi2S3 powders was investigated. Nanosized Bi2S3 colloids were obtained having long-term stability and showing a blue shift on the optical band edge; the presence of particles exhibiting quantum size effects is discussed. Morphological welldefined Bi2S3 particles were obtained in which the fiber-type morphology is prevalent.FCT - POCTI/1999/CTM/ 3545

SERS Research Applied to Polymer Based Nanocomposites

Polymer based nanocomposites containing metal nanoparticles (e.g. Au, Ag) have gained increased attention as a new class of SERS (Surface Enhanced Raman Scattering) substrates for analytical platforms. On the other hand, the application of SERS using such platforms can also provide new insights on the properties of composite materials. In this chapter, we review recent research on the development of SERS substrates based on polymer nanocomposites and their applications in different fields. The fundamentals of SERS are briefly approached and subsequently there is a reference to the strategies of preparation of polymer based nanocomposites. Here the main focus is on SERS studies that have used a diversity of polymer based nanocomposites, highlighting certain properties of the materials that are relevant for the envisaged functionalities. A final section is devoted to the joint use of Raman imaging and SERS in nanocomposites development, a topic that presents a great potential still to be explored as shown by the recent research in this field

Carbamazepine polymorphism: a re-visitation using Raman imaging

Raman imaging methods have appeared in the last years as a powerful approach to monitoring the quality of pharmaceutical compounds. Because polymorphism occurs in many crystalline pharmaceutical compounds, it is essential to monitor polymorphic transformations induced by different external stimulus, such as temperature changes, to which those compounds may be submitted. Raman imaging with k-means cluster analysis (CA) is used here as an essential technique to investigate structural and chemical transformations occurring in carbamazepine p-monoclinic (CBZ III) into carbamazepine triclinic (CBZ I) when submitted to temperatures near the melting point of CBZ III (178 °C) and CBZ I (193 °C). CBZ III commercial powder and laboratorial prepared CBZ I were analyzed by differential scanning calorimetry, powder X-ray diffraction and Raman spectroscopy with variable temperature. After thermal treatment, the resultant CBZ powder was evaluated by Raman imaging, in which all imaging data was analyzed using CA. Raman imaging allowed the identification of different polymorphs of CBZ (CBZ III and CBZ I) and iminostilbene (IMS), a degradation product of CBZ, in the treated samples, depending on the heating treatment method.publishe

Raman imaging studies on the stability of Paracetamol tablets under different storage conditions

The applicability of Raman imaging for pharmaceutics production ranges from the characterization of pharmaceutical formulations, kinetic processes in drug delivery to the rapid detection and identification of counterfeit drugs/contaminants. Acetaminophen (Paracetamol, APAP) is an analgesic and antipyretic drug and one of the most consumed medicines worldwide. On the other hand, the compound 4-aminophenol (4-AP) is a hydrolytic product of APAP with nephrotoxicity and teratogenic effects. In this work, we have explored for the first time Raman imaging methods to characterize the main components of commercial APAP tablets (APAP-tablets) and to inquire about the potential of this optical technique to identify 4-AP in APAP tablets, which have been previously spiked with such contaminant. The laboratorial treated APAP-tablet samples were subjected to different temperature, humidity and sunlight exposure conditions, mimicking storage conditions, and then the Raman spectra and images were collected to monitor changes that might occur in those conditions. Although the lower limit of detection of 4-AP in APAP-tablets is above the minimum levels established by Pharmacopoeias (0.005 %), this research demonstrates that Raman imaging still allows the detection of small amounts of the contaminant, thus opening perspectives for exploring this technique for characterizing APAP products.publishe

Glass-based biosensing device for monitoring CA15-3 cancer biomarker

We thank funding to the European Research Council, through the Starting Grant 3P’s (GA311086, given to MGFS) and to Norte 2020 - Programa Operacional Regional do Norte, through the project CANCER (NORTE-01-0145-FEDER-000029). The authors also thank due to CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013).info:eu-repo/semantics/publishedVersio