Browsing by Author "Raftery, James"

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    Bis(piperidinedithiocarbamato)pyridinecadmium(II) as a Single-Source Precursor for the Synthesis of CdS Nanoparticles and Aerosol-Assisted Chemical Vapour Deposition (AACVD) of CdS thin films
    (2014) Lewis, David J.; Revaprasadu, Neerish; Mlowe, Sixberth; Malik, Azad; Mubofu, Egid B.; O'Brien, Paul; Raftery, James
    The synthesis and single-crystal X-ray structure of bis(piperidinedithiocarbamato)pyridinecadmium(II), [Cd(S2C(NC5H10))2(NC5H5)] are reported and its use as a precursor for the synthesis of hexagonal CdS nanoparticles and CdS thin films is presented. Thermogravimetric analysis (TGA) of this complex showed clean decomposition in two steps to give CdS. Thermolysis of the complex in hexadecylamine at different temperatures in the range 190 ¬ 270 °C gave CdS nanostructures including nanorods and oval shaped particles. The band gap of the as-synthesized CdS nanoparticles varied as the temperature was increased. CdS thin films with optical direct band gaps of ca. 2.4 eV were deposited by aerosol-assisted chemical vapour deposition (AACVD) in the temperature range 350 to 450 oC using the same precursor. Powder X-ray diffraction (p-XRD) patterns of CdS nanoparticles and thin films confirmed the hexagonal phase of CdS.
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    Heterocyclic Dithiocarbamato-Iron (III) Complexes: Single-Source Precursors for Aerosol-Assisted Chemical Vapour Deposition (AACVD) of Iron Sulfide Thin Films
    (2016) Mlowe, Sixberth; Lewis, David J.; Malik, Mohammad A.; Raftery, James; Mubofu, Egid B.; O'Brien, Paul; Revaprasadu, Neerish
    The biomedical potential of flavonoids is normally restricted by their low water solubility. However, little has been reported on their encapsulation into polyamidoamine (PAMAM) dendrimers to improve their biomedical applications. Generation four (G4) PAMAM dendrimer containing ethylenediaminetetraacetic acid core with acrylic acid and ethylenediamine as repeating units was synthesized by divergent approach and used to encapsulate a flavonoid tetramethylscutellarein (TMScu, 1) to study its solubility and in vitro release for potential bioactivity enhancement. The as-synthesized dendrimer and the dendrimer–TMScu complex were characterized by spectroscopic and spectrometric techniques. The encapsulation of 1 into dendrimer was achieved by a co-precipitation method with the encapsulation efficiency of 77.8% ˘ 0.69% and a loading capacity of 6.2% ˘ 0.06%. A phase solubility diagram indicated an increased water solubility of 1 as a function of dendrimer concentration at pH 4.0 and 7.2. In vitro release of 1 from its dendrimer complex indicated high percentage release at pH 4.0. The stability study of the TMScu-dendrimer at 0, 27 and 40 ˝ C showed the formulations to be stable when stored in cool and dark conditions compared to those stored in light and warmer temperatures. Overall, PAMAM dendrimer-G4 is capable of encapsulating 1, increasing its solubility and thus could enhance its bioactivity.