Browsing by Author "Mgaya, James E."

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    Influence of heteroatoms on the optoelectronic properties of triphenylamine-based dyes for DSSCs application: A computational approach
    (Elsevier, 2022-02-23) Kirenga, Peter; Mkoma, Stelyus L.; Mlowe, Sixberth; Msambwa, Yohana; Kiruri, Lucy W.; Jacob, Fortunatus R.; Mgaya, James E.; Kinunda, Grace A.; Deogratias, Geradius
    A series of sensitizers with D-π-π-A architectural framework have been fine-tuned through a variation of het eroatoms (NH, O, Se, and Te) in the π-spacers. Cyanoacrylic acid and hydantoin were used as the acceptor groups. The geometrical and electronic properties were investigated through density functional theory (DFT) and time-dependent DFT (TD-DFT) , respectively. To determine stable dye-TiO2 configuration, the binding energies are reported. The driving force of charge injection and dye regeneration range between 0.00 to − 0.77 eV and − 0.133 to − 1.60 eV, respectively, suggesting spontaneous processes. Chalcogen heteroatoms (S, Se, and Te) improved absorption within the visible and NIR regions. The binding energies of dye on (TiO2)6 cluster range between − 8.32 to − 9.62 eV and − 7.77 to − 8.98 eV for cyanoacrylic acid and hydantoin dyes, respectively. The findings suggest that the inclusion Se and Te heteroatoms may boost the performance of DSSCs when compared to parent materials containing S.
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    Influence of heteroatoms on the optoelectronic properties of triphenylamine-based dyes for DSSCs application: A computational approach
    (Elsevier, 2022-02-27) Kirenga, Peter; Mkoma, Stelyus L.; Mlowe, Sixberth; Msambwa, Yohana; Kiruri, Lucy W.; Jacob, Fortunatus R.; Mgaya, James E.; Kinunda, Grace A.; Deogratias, Geradius
    A series of sensitizers with D-π-π-A architectural framework have been fine-tuned through a variation of heteroatoms (NH, O, Se, and Te) in the π-spacers. Cyanoacrylic acid and hydantoin were used as the acceptor groups. The geometrical and electronic properties were investigated through density functional theory (DFT) and time-dependent DFT (TD-DFT) , respectively. To determine stable dye-TiO2 configuration, the binding energies are reported. The driving force of charge injection and dye regeneration range between 0.00 to −0.77 eV and −0.133 to −1.60 eV, respectively, suggesting spontaneous processes. Chalcogen heteroatoms (S, Se, and Te) improved absorption within the visible and NIR regions. The binding energies of dye on (TiO2)6 cluster range between −8.32 to −9.62 eV and −7.77 to −8.98 eV for cyanoacrylic acid and hydantoin dyes, respectively. The findings suggest that the inclusion Se and Te heteroatoms may boost the performance of DSSCs when compared to parent materials containing S.
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    Isomerization of Anacardic Acid: A Possible Route to the Synthesis of an Unsaturated Benzolactone and a Kairomone
    (Wiley, 2014-09) Mgaya, James E.; Mubofu, Egid B.; Mgani, Quintino A.; Cordes, David B.; Slawin, Alexandra M. Z.; Cole‐Hamilton, David J.
    Crystalline unsaturated lactone, 8-hydroxy-3-tridecyl-1H-isochromen-1-one (6) has been synthesized by isomerization of anacardic acid having heterogeneous alkyl side chains (a mixture of mono-, di-, and tri-unsaturated anacardic acid) (1). Hydrogenation of 8-hydroxy-3-tridecyl-1H-isochromen-1-one produced a saturated lactone, 8-hydroxy-3-tridecyl-3,4-dihydroisochromen-1-one (7). Isomerization of monoene anacardic acid resulted in a crystalline isoanacardic acid, (E)-2-hydroxy-6-(pentadec-1-enyl)benzoic acid (8) as a major product. This was then metathesized with 2-butene to give 3-prop-1-enylphenol (10). Both isomerization reactions used a 1,2-bis(ditertiarybutylphosphinomethyl)benzene modified palladium catalyst. The two products, 8-hydroxy-3-tridecyl-1H-isochromen-1-one and (E)-2-hydroxy-6-(pentadec-1-enyl)benzoic acid have been crystallographically characterized.
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    Isomerization Of Anacardic Acid: A Possible Route To The Synthesis Of An Unsaturated Benzolactone And A Kairomone
    (Wiley, 2014-08) Mgaya, James E.; Mubofu, Egid B.; Mgani, Quintino A.; Cordes, David B.; Slawin, Alexandra M. Z.; Cole‐Hamilton, David J.
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    Isomerization of Anacardic acid: A Possible Route to the Synthesis of an Unsaturated Benzolactone and a Kairomone
    (2014-08) Mgaya, James E.; Mubofu, Egid B.; Mgani, Quintino A.; Cordes, David B.; Slawin, Alexandra M. Z.; Cole‐Hamilton, David J.
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    Synthesis of Bifunctional Monomers by the Palladium-Catalyzed Carbonylation of Cardanol and its Derivatives
    (Wiley, 2016) Mgaya, James E.; Bartlett, Stuart A.; Mubofu, Egid B.; Mgani, Q. A.; Slawin, Alexandra M. Z.; Pogorzelec, Peter J.; Cole‐Hamilton, David J.
    A 1,2-bis(di-tert-butylphosphinomethyl)benzene-modified palladium catalyst has been used to synthesize bifunctional monomers of different chain lengths from cardanol. Short-chain derivatives of cardanol, such as (E)-3-(dodec-8-enyl)phenol; HOPhC12-ene, (E)-3-(undec-8-enyl)phenol; HOPhC11-ene, (E)-3-(dec-8-enyl)phenol; HOPhC10-ene, and 3-(non-8-enyl)phenol; HOPhC9-ene, were synthesized by the metathesis of cardanol with symmetrical internal alkenes. These derivatives were methoxycarbonylated to produce monomers with different chain lengths such as methyl-16-(3-hydroxyphenyl)hexadecanoate; HOPhC15COOMe, methyl-13-(3-hydroxyphenyl)tridecanoate; HOPhC12COOMe, methyl-12-(3-hydroxyphenyl)dodecanoate; HOPhC11COOMe, methyl-11-(3-hydroxyphenyl)undecanoate; HOPhC10COOMe, and methyl-10-(3-hydroxyphenyl)decanoate; HOPhC9COOMe, respectively. Polymerization of the synthesized monomers produced oligomers that consist of up to seven monomer units as confirmed by MALDI-TOF-MS. Lactone formation was also observed in some cases under polymerization conditions.
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    Synthesis of Bifunctional Monomers by The Palladium-Catalyzed Carbonylation Of Cardanol And Its Derivatives
    (2016-02) Mgaya, James E.; Bartlett, Stuart A.; Mubofu, Egid B.; Mgani, Quintino A.; Slawin, Alexandra M. Z.; Pogorzelec, Peter J.; Cole‐Hamilton, David J.
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    Synthesis of Bifunctional Monomers by the Palladium-Catalyzed Carbonylation of Cardanol and Its Derivatives
    (2016-02) Mgaya, James E.; Bartlett, Stuart A.; Mubofu, Egid B.; Cole‐Hamilton, David J.