Browsing by Author "Fiebor, Alphonse"

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    Nutritional composition and antioxidant properties of three varieties of carrot (Daucus carota)
    (Elsevier, 2021) Boadi, Nathaniel Owusu; Badu, Mercy; Kortei, Nii Korley; Saah, Selina Ama; Annor, Benjamin; Mensah, Michael Baah; Okyere, Harry; Fiebor, Alphonse; 0000-0002-8080-4812
    Carrots are a potentially rich source of antioxidants in addition to their nutritional proper ties. In this study, the nutritional composition and antioxidant properties of three varieties of carrots, namely Kuroda, Pamela and Amazonia cultivated in Ghana were determined. The peroxide scavenging method was used to determine the antioxidant properties of the ethanolic extracts of the carrot varieties at different concentrations. The protein, crude fi bre, fat and carbohydrate contents of the carrot varieties ranged 6.46 – 10.73 %, 7.18 – 8.87 %, 1.97 – 4.31 % and 6.25 – 8.39 % respectively. The three varieties had high moisture contents ranging from 69.06 to 75.30 %. The antioxidant properties were high even at low concentrations of extract, and their activity increased with time in the order Amazonia > kuroda > pamela. Amazonia had the highest fibre, protein and carbohydrate contents and the lowest moisture content, making it the most preferred variety.
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    Water-soluble SNS cationic palladium(II) complexes and theirSuzuki–Miyaura cross-coupling reactions in aqueous medium
    (Beilstein-Institut, 2018-07-23) Fiebor, Alphonse; Tia, Richard; Makhubela, Banothile C. E.; Kinfe, Henok H.
    Unlike their SCS analogues, SNS pincer complexes are poorly studied for their use in coupling reactions. Accordingly, a series ofwater soluble cationic Pd(II) SNS pincer complexes have been successfully synthesised and investigated in detail for their catalyticactivity in Suzuki–Miyaura coupling reactions. By using only 0.5 mol % loading of the complexes, the coupling of inactivated arylbromides and activated aryl chlorides with various boronic acids in water was achieved in excellent yields and the catalysts werefound to be reusable for three cycles without a significant loss of activity. The investigation of the mechanism of the reactionrevealed that a Pd(II) to Pd(IV) route is the more likely pathway which was further supported by computational studies.