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Geethika K. Weragoda

Geethika K. Weragoda
The Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia

PhD, University of Cincinnati, Ohio, USA

About

15
Publications
589
Reads
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130
Citations
Additional affiliations
September 2010 - present
University of Cincinnati
Position
  • Graduate Researcher

Publications

Publications (15)
Article
The ternary Pd complexes [(phen)Pd(H)]+ (1-Pd) and [(phen)Pd(CH3)]+ (5-Pd) (where phen = 1,10-phenanthroline) both react with hexane in a linear ion trap mass spectrometer, forming the C-H activation product [(phen)Pd(C6H11)]+ (3-Pd) and releasing H2 and CH4, respectively. Density functional theory (DFT) calculations agree well with the experiments...
Article
Acceptorless dehydrogenation of ethane was achieved in the gas phase via a two-step catalytic cycle involving ternary cationic metal hydrides, [(phen)M(H)]+, 1, and metal ethides, [(phen)M(CH2CH3)]+, 2, (where M = Ni, Pd, or Pt, and phen = 1,10-phenanthroline). Species 1 and 2 were generated and their reactivity studied in a quadrupole ion trap mas...
Article
Using fatty acids as renewable sources of biofuels requires deoxygenation. While a number of promising catalysts have been developed to achieve this, their operating mechanisms are poorly understood. Here, model molecular systems are studied in the gas phase using mass spectrometry experiments and DFT calculations. The coordinated metal complexes [...
Article
We report a new visible light‐mediated carbonylative amidation of aryl, heteroaryl and alkyl halides. A tandem catalytic cycle of [Ir(ppy) 2 (dtb‐bpy)] + generates a potent iridium photoreductant via a second catalytic cycle in the presence of DIPEA which productively engages aryl bromides, iodides and even chlorides as well as primary, secondary a...
Article
A photoredox‐catalyzed radical carbonylative amidation of aryl, heteroaryl, and alkyl halides has been developed. The tandem catalytic cycle of [Ir(ppy)2(dtb‐bpy)]⁺ engages aryl bromides, iodides, and chlorides as well as primary, secondary, and tertiary alkyl iodides through a multiphoton‐initiated secondary catalytic cycle. In combination with co...
Preprint
p>We report a new visible light-mediated carbonylative amidation of aryl, heteroaryl and alkyl halides. A tandem catalytic cycle of [Ir(ppy)<sub>2</sub>(dtb-bpy)]<sup>+</sup> generates a potent iridium photoreductant via a second catalytic cycle in the presence of DIPEA which productively engages aryl bromides, iodides and even chlorides as well as...
Article
The combination of multistage mass spectrometry experiments employing the distonic radical approach together with DFT calculations are used to examine addition of the N-methyl-pyridinium-4-yl radical cation (γ-NMP) to iso(thio)cyanates in the gas-phase. The type of products formed depend on the nature of the iso(thio)cyanate: (1) hydrogen atom abst...
Article
The general catalytic synthesis of aryl and vinyl thioethers from readily available halides remains a challenge. Herein we report a unified method for the thiolation of aryl and vinyl iodides with dialkyl disulfides using visible light photoredox catalysis. A range of thioether products bearing diverse functional groups can be accessed in high yiel...
Article
Irradiation of 3-methyl-2-phenyl-2H-azirine (1) at 254nm in argon matrices results in ylide 6. Similarly, laser flash photolysis (λ=266nm) of azirine 1 in acetonitrile yields ylide 6, which has a transient absorption with λmax at ∼340nm and a lifetime of 14 μs. Density functional theory calculations were preformed to support the characterisation of...
Article
Laser flash photolysis of cyclopropyl(phenyl)methanone 6 in argon-saturated methanol yields the triplet ketone (T1K) of 6 that is formed with a rate constant of ~1.7 × 107 s−1 (λmax = 360 nm) and has a lifetime of ~1.4 µs. T1K of 6 decays to form ketyl radical 7 (λmax ~300 nm), which dimerizes to form photoproducts, pinacol derivatives 8 and 9. In...
Article
Nanosecond laser flash photolysis of o-hydroxyacetophenone (1a) and 2,4-dihydroxyacetophenone (1b) in ethanol and acetonitrile results in absorption due to triplet biradicals 2a (λmax 430 nm, τ ≈ 3 μs) and 2b (λmax 400 nm, τ ≈ 1 μs), respectively. Triplet biradical 2a intersystem crosses to form Z-3a (λmax 400 nm, τ ≈ 10 μs), whereas 2b forms both...
Article
Photolysis of 3-methyl-2-phenyl-2H-azirine (1a) in argon-saturated acetonitrile does not yield any new products, whereas photolysis in oxygen-saturated acetonitrile yields benzaldehyde 2, by intercepting vinylnitrene 5 with oxygen. Similarly, photolysis of 1a in the presence of bromoform allows the trapping of vinylnitrene 5, leading to the formati...
Article
Photolysis of 1 in argon-saturated acetonitrile yields 2, whereas in oxygen-saturated acetonitrile small amounts of benzoic acid and benzamide are formed in addition to 2. Similarly, photolysis of 2 in argon-saturated acetonitrile results in 1 and a trace amount of 3, whereas in oxygen-saturated acetonitrile the major product is 1 in addition to th...

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